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Opinion and editorial content included in the
Dair-e-news
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Special Report - ADSA Annual Meeting Coverage
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Welcome to the ADSA Annual Meeting Dair-e-news
Presentations at the 2020 ADSA Virtual Annual Meeting have concluded. The premier global dairy science meeting that went to homes and offices around the world was a great success with over 2,300 individuals registered for the meeting. This makes it one of the largest scientific meetings focused on
dairy ever held. Information shared will make a difference in the industry for years to come. All content on the Virtual Annual Meeting site (
virtual2020.adsa.org
) was recorded and will be available to registered attendees at that web link and accessed using your username and password through August 24, 2020.
We were pleased to send "Daily Special Editions" of this newsletter once again to you from the meeting. An outstanding group of graduate students worked with us to help provide daily coverage of scientific sessions and other activities taking place throughout the meeting. We greatly appreciate their help. This year’s writers were:
Bailey Basiel Penn State
Kayla Alward Virginia Tech
Yunna Wang University of Wisconsin-Madison
Meghan Connelly University of Wisconsin-Madison
Miriam Snider University of Vermont
Ashley Putman Michigan State University
Kaavya Rathnakumar South Dakota State University
Abigail Krentz The Ohio State University
Shayanti Minj South Dakota State University
Timothy Lott Cornell University
Bo Zhang UC Davis
Arup Ratan Sen The University of Tennessee
Haley Zynda The Ohio State University
Shivani Badiger The Ohio State University
Sonali Raghunath University of Minnesota
Iswarya Rajesh University of Alberta
Save the date for next year's annual meeting in Louisville, Kentucky, July 11-14, 2021. We will see you there.
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Our apologies for yesterday's broken link
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Conversation with ADSA's Richard Erdman
Incoming American Dairy Science Association President, Richard Erdman talks with us about his plans for the coming year as well as this year's virtual event experience.
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Glucose infusion during heat stress restores normoglycemia
but does not improve milk production
By Meghan Connelly
During lactation the mammary uptakes somewhere between 60-85% of total circulating glucose. This glucose is used to synthesize lactose, with lactose being the primary osmoregulator of milk. Additionally, glucose is a critical molecule for generating lipids and proteins involved in milk synthesis. Unfortunately, while glucose is important, dairy cows often experience interruptions in glucose’s supply to the mammary gland during times of heat stress. Heat stress results in increased maintenance costs and reduce dry matter intakes, further compounding the challenge of reduced glucose supply. Researchers at Virginia Tech wanted to determine if additional glucose supplied in the form of dextrose could alleviate the challenge of heat stress and its impact on milk yield, and found the answer to that is a bit more complex than just additional available glucose precursor.
Stewart and colleagues set out to test how bringing heat stressed cows out of hypoglycemnia would improve milk production during heat stress. Cows were thermoneutral for 10 days, then placed on a 15 day heat stress period, with the last 4 days of the heat stress period cows being continually infused with dextrose. Unsurprisingly, heat stress reduced blood glucose concentrations, as well as a corresponding decline in feed intake. Interestingly, dextrose infusion did not rescue milk production, with a numerical decline in heat stress + dextrose infused cows relative to the previous heat stress alone.
These results followed with previous studies examining heat stress, with increased rectal temperatures and respiratory rates, decreased feed intake and hypoglycemia. Upon termination of heat stress, cows returned to normoglycemia. Interestingly, dextrose infusion did not improve feed intake or milk production relative to heat stress treatment. Collectively, this study suggests energy allocation during heat stress is much more complex than simply providing glucose as a precursor and that hypoglycemia is not the limiting factor for limited milk production in the heat stressed dairy cow.
Meghan Connelly is a PhD student in Dr. Laura Hernandez’s lab at the University of Wisconsin – Madison. Her research focuses on calcium and serotonin metabolism and how each are regulated by the mammary gland.
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Reproduction and farm profitability
By Arup Ratan Sen
Reproduction is one of the key performance indicators of dairy farm success. In this year’s American Dairy Science Association Annual meeting, researchers presented different studies highlighting how reproductive management could improve farm profitability.
Accurate and efficient detection of estrus is essential for effective reproductive management. Researchers at the University of Minnesota explored the predictive ability of an estrus prediction model developed based on an activity and rumination monitoring system in organic and a low-input conventional dairy herd. Estrus detection performance of the activity and rumination monitoring was better during winter compared to summer in any management system. However, the monitoring of activity and rumination was not effective during grazing period. Their estrus predictive model performed reasonably well under different herds and seasons.
Beside reproductive performance, lower herd turnover rate (TR), tailored calf culling, and maintaining required number of replacement heifer influence farm profitability. Researcher at the University of Wisconsin-Madison explored the effects of reproduction and herd structure on farm profitability. Their results showed that farm net return and cow longevity increased with herd turnover rate between 45 to 25%. Higher pregnancy rate within 21d increased farm net return, however, greater replacement heifer rearing cost reduced the net return. They suggested that maintaining optimal herd structure by controlled culling and rearing only the required replacement heifer and improving reproductive performance could increase farm profitability.
To evaluate the economic impact of recent trend of using sexed and beef semen in dairy cows, researcher at the University of Wisconsin-Madison utilized a whole-farm integrated simulation model, named Ruminant Farm System model (RuFaS). Their study showed that using 40% and 15% sexed semen in the 1
st
and 2
nd
lactation cows, respectively, and beef semen in all other cows resulted in $140 more net return per cow per year, compared to the conventional semen use.
Arup Ratan Sen is from Bangladesh. He is currently a Ph.D. student at the University of Tennessee under the mentorship of Dr. Elizabeth Eckelkamp, focusing on producers’ perception of farm management that impacts their permanency in the dairy industry.
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Wildfire consequences related to poor health
By Ashley Putman
Climate change requires dairy producers to make adaptations in order to maintain a healthy herd and quality milk. Climate change has been associated with extreme weather conditions, such as drought, severe temperatures, and volatile storms. Wildfires are included in the list of weather events that have been impacted by climate change. Indeed, the frequency, intensity, and duration of wildfires are expected to continue increasing in the future. Besides the direct damage of burning, wildfires also substantially reduce air quality by increasing fine particulate matter, which has been associated with negative health outcomes in humans.
Given the association between negative impacts and fine particulate matter in humans, it is reasonable to think that dairy cattle might be affected adversely during wildfire season due to the increases of fine particulate matter during this time. At the University of Idaho, a group investigated if increases of fine particulate matter, present during wildfire season, were associated with disease incidence and altered milk production in dairy cows. One farm provided daily health records during wildfire season over the course of four years while a second farm provided milk yield and milk components data every other month. These parameters were compared to weather data, including particulate matter, collected from local monitoring stations with particulate mapping being utilized to determine the likelihood that increased particulate matter was related to wildfires. Anderson reported that local wildfires were likely responsible for increased particulate matter and this higher particulate matter was associated with increased general illness, mastitis, and calf death. Milk yields and components did not appear to have any significant associations with increased particulate matter, however it was noted that these relationships may have been influenced by the infrequent data collection for these parameters. Therefore, the authors concluded that negative health outcomes are associated with exposure to large amounts of fine particulate matter. Results such as those reported in this study emphasize the need for understanding climate change consequences on dairy cow health and production.
Ashley Putman is a recently graduated veterinarian and PhD candidate in the Meadow Brook Endowed Laboratory at Michigan State University. Under the guidance of Dr. Lorraine Sordillo, she focuses on the physiological role of isoprostanes, a biomarker of oxidative stress, on bovine health and disease.
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Glucose tolerance appears to follow a daily rhythm in dairy cows
By Meghan Connelly
Glucose is an essential metabolic fuel for dairy cows, specifically due to its essential requirement for milk lactose synthesis. Additionally, during immune system challenge, glucose requirements increase significantly as the immune system is activated and continues function. Glucose has been shown to be regulated by circadian rhythms, with circadian rhythms coordinating physiology and behavior across the day and being governed by clock transcription factors. While, glucose tolerance follows a circadian rhythm in non-ruminants it’s unknown if a similar rhythm follows in dairy cows. Researchers discovered that it did in fact follow a daily rhythm, and may be a potential advantage when discussing how to aid metabolism in the dairy cow via different management strategies.
Researchers set out to answer this question using 12 cows divided into two replicated blocks (n=6/block). Intravenous glucose tolerance tests were conducted at 4 times to represent every 6h across the day. Additionally, cows were fed 12x/day to stabilize feed intake. Baseline glucose concentrations didn’t follow a daily rhythm, however baseline insulin followed a 24h daily rhythm as well as insulin release fitting a similar pattern to the daily rhythm. The rate of glucose uptake followed a daily rhythm, being greatest during mid-day; however, insulin increases did not correspond to increases in glucose disappearance.
These data suggest that insulin sensitivity, not insulin release may be the responsible factor for daily rhythms in glucose disappearance. Glucose tolerance follows a daily rhythm, with higher glucose tolerance in morning and afternoon time periods relative to overnight. Interestingly, glucose concentration did not follow a 24h rhythm during 12x/d feeding suggesting that is dependent upon the pattern of daily feed intake. These results suggest that the circadian rhythm of glucose tolerance is influenced across the day and that understanding how to use this to benefit metabolism in the dairy cow may be a useful management strategy.
Meghan Connelly is a PhD student in Dr. Laura Hernandez’s lab at the University of Wisconsin – Madison. Her research focuses on calcium and serotonin metabolism and how each are regulated by the mammary gland.
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Bull side of fertility, puberty in heifers and pregnancy
By Kayla Alward
The Monday, Block 4 Breeding and Genetics section saw a large focus on male fertility with talks on the role of the X chromosome in male fertility, targeted sequencing to identify deleterious mutations, comparing bull fertility across countries and the conception rate of beef sires bred to dairy cows. The male topic was broken up with talks on variation in timing of puberty in heifers, models for genetic analysis of pregnancy loss and the relationship of the cow and calf’s microbiome.
Researchers from the University of Florida sought to increase the accuracy of predictions for bull fertility by including sex chromosomes in genomic predictions. They found that predictive ability of genomic models was improved when the X chromosome was included, indicating the importance of the X chromosome on male fertility in dairy cattle. They confirmed this model’s improvement was due to the biological role of the SNPs on the X chromosome by running this model with the same amount of SNPs in both the autosomal and X chromosome and just the autosomal model and found similar predictive correlations.
Also, at the University of Florida, researchers identified causal mutations underlying bull fertility by performing targeted sequencing of 5 genomic regions previously identified using the GWAS. They identified 15 codon mutations that were distinct in high vs. low fertility bulls, as characterized by sire conception rate, that are affecting dairy bull fertility.
UF researchers also evaluated across-country genomic predictions of bull fertility in Jersey dairy cattle through sharing of reference data. 1500 US and 600 Australia bulls were evaluated, with results showing no clear genetic characterization of population between countries, indicating that genomic prediction of bull fertility is feasible in dairy cattle. Interestingly, the US Jersey population presented higher genetic similarity than the AU Jersey population, which showed a mix of US and New Zealand Jersey background.
The final presentation on bull fertility focused on providing a tool for dairy producers to evaluate beef bulls as service sires on the dairy operation. Data from 268,000 matings with the majority of the matings between Angus and Holstein were analyzed. Sire Conception Rate proved a useful ranking tool for beef bulls by fertility that translates to dairy breeds.
Switching to the female side, our first presentation focused on the variation in timing of puberty in New Zealand heifers, with a goal of accelerating genetic gain in fertility through increasing Fertility Breeding Value. A preliminary study ranking 500 animals by FBV found high FBV animals reached puberty 21 days sooner at a 25 kg lighter weight. This study was replicated on a larger scale with 5000 animals and preliminary results show that a vast difference existed between the 54 herds in age of puberty. Age at puberty has a promising heritability of 0.36 when using progesterone sampling, while other fertility traits already used have a heritability around 0.05.
Continuing the female path, researchers at the University of Florida analyzed 24,000 abortion records across multiple models to find that pregnancy loss is a heritable trait and therefore, selection for reduced pregnancy loss is feasible. Spearman rank correlations ranged from 0.2 to 0.9, showing a reranking of bulls by model. However, the goodness of fit indicated the non-linear model a better choice for analyzing pregnancy loss in dairy cattle.
The final talk by researchers at Virginia Tech linked the maternal and calf microbiome, with important implications in predicting calf health. Holstein cows were monitored for calving with vaginal, placental, fecal and colostrum samples collected. Immediately after birth, the calf was isolated and fecal samples were collected. Results showed moderate correlations of the dam vagina and oral sample with the calf 24-hour fecal sample. Maternal fecal sample correlation to calf fecal sample increased as the calf aged. This indicates that the dam microbiome may be used to predict early calf fecal microbiome, with implications of calf disease and immunity.
Kayla Alward is a PhD student at Virginia Tech under Dr. Rebecca Cockrum. She earned her B.S. in Animal Science and Dairy Science as well as M.S in Animal Science from the University of Georgia. Her current research explores the relationship between photoperiod, circadian rhythms and colostrum quality and reproduction.
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Disease susceptibility, prediction during transition period explored
By Arup Ratan Sen
Dairy cow adapts their physiological and behavioral processes in response to the stresses during transition period. These changes in the physiological and behavioral processes could alter their susceptibility to transition cow diseases. Identifying these changes could also aid in disease prediction. Researchers from different universities presented their findings regarding disease susceptibility and prediction during transition period in this year’s American Dairy Science Association Annual Meeting.
Dairy cow utilizes stored body nutrients to support fetal development and milk production. Transition cow diseases might alter nutrient metabolism and consequently affect cow and calve health. Researcher at the University of Idaho explored the relationship between fat-soluble vitamins and dairy cow health status. Their study revealed that blood concentration of vitamin A, E, and β-carotene was affected by transition cow diseases. Vitamin A concentration in blood was greater in mastitic cow. They suggested this could affect calves' vitamin A concentration and health. Susceptibility to metabolic disorders during the transition period, however, partly determined by differential regulation of hepatic metabolism by mRNA expression, suggested the researcher at the University of Wisconsin-Madison.
Diseases during the transition period may alter the behavioral, physiological, and performance parameters of the dairy cows. Researchers from Cornell University studied these parameter changes through sensors and applied machine-learning techniques to predict health disorders in transition Holstein cows. Reduced resting time and increased rumination behavior was observed in cow around the day of clinical diagnosis of displaced abomasum (DA), ketosis (KET), and indigestion. The reticulo-rumen temperature in those cows started increasing on day 1 of the clinical diagnosis of diseases. Milk yield was lower in cows diagnosed with DA, KET, and indigestion, compared to the healthy cows, while milk fat percentage was higher in the diseased cows compared to the healthy cows. They found that effective prediction of health disorders could be done through machine learning by combining environmental sensor data and non-sensor data from multiple cows. Among the machine learning technique used, Gradient Boost Decision Tree technique had the highest predicting ability of health disorders.
Arup Ratan Sen is from Bangladesh. He is currently a Ph.D. student at the University of Tennessee under the mentorship of Dr. Elizabeth Eckelkamp, focusing on producers’ perception of farm management that impacts their permanency in the dairy industry.
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Out with 'bad' in with 'good': New impacts of silage inoculation
By Miriam Snider
Silage is an important method of feeding livestock during times when pasture isn’t at its best quality or is in short demand. Due to variables such as weather, covering speed, quality, variety, and packing density, silage crops will always vary. Forage crops utilized for silage contain microorganisms, which can be “good” or “bad,” with bad microorganisms, such as
Clostridia, Bacilli,
yeast, and molds negatively impacting silage quality. Silage inoculants may contain live bacteria and enzymes; these are typically “good” bacteria, such as anaerobic lactic acid bacteria,
Enterococcus,
or
Pedicoccus,
that enhance efficient fermentation and “preserve” the forage. Some common end products of fermentation are lactic acid, acetic acid, ethanol, and carbon dioxide. However, inoculants, no matter how good, are not always successful, in which producers may see spoilage, undesirable fermentation products, and major dry matter losses. In the first block of the Tuesday session of Forages and Pastures, moderated by Dr. Daryl Kleinschmit, researchers present data encompassing the usage of microbial inoculants and their roles in spoilage and milk production as well as different methodologies that impact fermentation characteristics.
In the first presentation, Killerby et al. presented a meta-analysis discussing the effects of microbial inoculants in regards to hay spoilage. Over 400 papers were analyzed with response variables such as dry matter, sugars, moldiness, temperature, NDF, IVDMD, ADIN, and heat degree days. It was found that there were no significant differences between treated and untreated hay regarding dry matter loss, moldiness, maximum temperature, IVDMD or heat degree days. Sugar concentrations were decreased in legume hay, but preserved more so in grass hay. NDF and ADIN showed similar decreases in legume hay. However, ADIN was increased in high moisture hays; this may be due to mehler reactions still occurring. Based on these results, it was concluded that microbial inoculants failed to preserve high moisture high. This reflects the inability of lactic acid bacteria to grow in hay that is stored at moisture levels lower than 35%.
Eisner et al. discussed the effects of silage inoculants on milk production. The objective of this study was to determine the impacts of reducing concentrates while simultaneously feeding inoculated forages on milk production and feed intake. Grass silages (1
st
and 2
nd
cut) and whole plant maize silage were ensiled with an inoculant or without. Thirty-two mid-lactation Holstein dairy cows were fed in a crossover feeding study. Each animal was individually supplemented with concentrates in feeding stations according to lactation stage and milk production. Cows fed inoculated forages tended to produce more milk than cows on the control diet, although milk did tend to have a 0.1% lower fat content. These results indicate that including an inoculant with forages allowed for a reduction in daily concentrate intake without negatively impacting fat and protein corrected milk.
Next, researchers from Lallemand discussed the effects of
Lactobacillus buchneri
inoculation when mixed with
Lactobacillus hilgardii
and
Pedicoccus pentosaceus
on fermentation parameters and the microbiome of corn silage. An ensiling trial was performed using hybrid corn silage with treatments consisting of a control (tap water),
L. buchneri
(LB), and a combination of two heterofermentative and homofermentative bacterial strains (Combo). Mini-silos were opened at days 30, 60, and 180. Bacterial composition was sequenced and fermentation parameters, organic volatile compounds, aerobic stability, and nutritional parameters were evaluated. At all 3 timepoints, or openings, lactic acid concentration was similar between the control and Combo treatment, but lower in LB silage. The Combo silage had greater lactate:acetate ratios, indicating that homofermentation was occurring. 1,2-Propandiol was greatest in LB and at its lowest concentrations in control silage. Propionic acid could not be detected in samples. When compared with LB, the Combo silage decreased losses of fresh matter at all three openings, as well as decreasing dry matter losses. When compared with the sequenced microbiome (predominately
Lactobacillaceae
), it was confirmed that different bacterial strains will improve aerobic stability.
Finally, Eisner et al. presented for a second time and presented their results discussing the effects of microbial inoculation on fermentation and aerobic stability of different maturities of rye. Rye was harvested at four stages of maturity and enisled immediately at the flowering, milk, and soft-dough stage. If harvested at the boot stage, rye was either ensiled immediately or after 24 hours field wilting. Five mini-silos for each treatment (control, inoculant) were filled with rye and stored for 60 days at 20C. An aerobic stability test was conducted after fermentation, monitoring the temperature inside each mini-silo. It was found that the use of an experimental inoculant enhanced acetate levels at all maturity stages while deceasing butyrate levels at all maturity stages. This demonstrates that an experimental inoculant is beneficial on fermentation and stability in rye from boot to soft-dough maturity stages.
Miriam Snider is a PhD candidate at the University of Vermont under Dr. Sabrina Greenwood. She earned her B.S. in Animal Science / Biology from Southeast Missouri State University and her M.S. from the University of Kentucky. Her current research explores forage and pasture quality/ energetics and its relationship with rumen fermentation and methane production in grassfed dairy cattle.
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Healthy mammary quarters neighboring LPS-infused quarters undergo hypogalactia associated with transcriptional changes in immune and metabolic genes
By Meghan Connelly
Mastitis is a costly disease for the dairy industry, for both cow and producer. Resulting in both a reduction in milk yield and change in composition. At the local level, inflamed quarters are easily identified; however, systemic inflammation occurs simultaneously in the neighboring, non-inflamed quarters. Which led researchers at the University of Missouri – Columbia to ask, what mechanisms regulate these outcomes in non-inflamed quarters? The primarily interest was in inflammation and its outcomes, rather than the infection itself. So, their objective was to determine how inflammation alters the mammary transcriptome of inflamed and neighboring glands over time and the pathways and genes regulated by this inflammation.
At the cow-level, cows were treated intramammarily with 50
μg
E. coli
LPS, saline (control) infusion or no infusion at the quarter level. Systemic responses occurred within 3 hours of LPS challenge, with increased rectal temperatures, as well as a reduction in milk production at the milkings following LPS treatment. Interestingly, LPS-treated quarters and their neighboring quarters had lower milk yield when compared to control quarters. Further, a local SCC response occurred in LPS-treated quarters, but not in neighboring quarters. And when researcher’s evaluated the transcriptomics at 3h after LPS-treatment, immune response pathways were upregulated and calcium signaling and tight junction pathways were down-regulated. When looking across time, both local and systemic responses occurred at 3h after treatment, leading researchers to believe cross-talk between glands may be occurring. Interestingly, systemic changes also occurred at 12h after treatment, with changes in metabolic genes.
Collectively, healthy quarters respond to systemic inflammation initially by upregulating immune genes, and then transitioning to modifying genes with metabolic functions. This research demonstrates that neighboring glands are also affected by systemic inflammation responses and can then shift their responses to metabolic and cellular metabolism. Potentially explaining the reduction in milk yield seen in neighboring glands, in addition to the infected gland. Further research to delve deeper into the candidate genes and pathways that were discovered is needed to confirm their relevance in the reduction of milk yield, but these data demonstrate how local and systemic responses to LPS impact local quarter inflammation and metabolism, as well as neighboring quarters.
Meghan Connelly is a PhD student in Dr. Laura Hernandez’s lab at the University of Wisconsin – Madison. Her research focuses on calcium and serotonin metabolism and how each are regulated by the mammary gland.
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Online learning: So now what?
By
Miriam Snider
What do you do when faced with the transition online, especially when you have hands on courses or lab courses? During this roundtable discussion, strategies and ideas were discussed to help instructors transition to online teaching, as well as learn how to engage students through distance learning.
To begin the session participants were asked to keep three questions in mind:
·
Will you be teaching a course, or a component of a course, for the first time in Fall 2020?
·
Do you feel that your institution is providing sufficient guidance to adequately your course online?
·
What is your biggest concern in regards to transitioning to online learning?
Dr. Caitlin Foley opened up the roundtable with her talk entitled “Transition from Live to Online Learning.” She still considers the transition to online learning to be a work in progress. Foley stated that she asked herself questions: What do I do first? What can I do? How do I make this worthwhile? What do students need? Am I preparing them for future coursework? She encouraged participants to think in a smart way and adjust their syllabi and objectives accordingly. It can be tricky for larger classes, especially as students now have to obtain information in a different manner as we transition to distance learning, rather than online learning. Dr. Foley encouraged listeners to make methods that work well for students. This includes creating extra credit opportunities, making engaging assignments, and being consistent and realistic about lab courses. Challenges will set in when it comes to designing assignments, writing exams, and making quiz questions, which can be very tricky for an online platform. The three main takeaways from this discussion were to be
realistic with yourself, learning objectives, and assignments.
Consistency is key! Finally, be
flexible with extra credit and office hours.
Dr. Jillian Bohlen was the next speaker discussing “Strategies to Engage Students in the Online Format.” She recognizes that there are some challenges with online learning such as the loss of facial expressions, gestures, and body language. In this talk, Dr. Bohlen encourages participants to be engaging in every aspect. For example, instructors should be engaging and consistent with information delivery as students like organization. However, mechanization from organization can create a loss in personal interactions so it may be helpful to have students help create or have a voice in your syllabus. Because students interact with information differently, Bohlen advised participants to utilize more than one delivery format. For example, make a 50-minute lecture class is a 15 – 20-minute overview lecture with reading materials. Make a video for students and perhaps make an interactive assignment. It is crucial to remain cognizant of capabilities, whether that be technology or time conflicts. Bohlen has found that engaging students with each other through the creation of working groups with periodic check-ins has been helpful as students will engage with others in ways that instructors cannot. She has also found that engaging with students by humanizing yourself makes one relatable, and therefore, engaging. As a parting thought, Dr. Bohlen said to allow flexibility in communication.
Dr. Stephanie Ward delivered a talk regarding “Assessment and Expectations: What I learned from Online Instruction.” Like the speakers before her, she found it to be a challenge to fit online assignments into a traditional grading scale. It should be expected that basically everything is open book. Assessments could be a combination of traditional and experiential methods. She said she also relied heavily on chat and discussion functions to give a classroom feel Dr. Ward said that for her that things worked best for her when entire units were posted in advance. This allowed for facilitation with teaching assistants. Like speakers before her, Dr. Ward said not expect for things to happen overnight.
Dr. Ben Wenner discussed in his talk entitled “Strategies for Transitioning Labs Online” methods that he has found useful when transitioning to online labs. This included:
·
Recorded Demonstrations
o
Dr Wenner said that this method gives the student opportunities to slow a video down or repeat, make searchable digital notes, review material ad libitum, and may even help instructors reach new audience.
·
Live demonstrations can also be helpful. The key is to be genuine; try not to sound rehearsed or forced!
·
Virtual drag and drop labs
·
Try it yourself learning: Although Dr. Wenner said that this has proved beneficial, it does take a lot of planning and detailed instructions.
·
Try together learning: with this method, Dr Wenner says to mail the materials for activities later.
o
With this style of learning, there are opportunities to follow along at home, repeat at a later time, record for review or reflection, and the ability to challenge student learning with hands-on experiences. The biggest hindrance to this method is the amount of time it takes to plan in advance.
·
Make it yourself: In this style of lab learning, students develop materials for each other.
Dr. Daniel Poole offered unique insight into “Transitioning a Dairy Management Course Online.” When switching to an online environment, hands-on problem solving disappears Dr. Poole advised instructors to use videos in an unscripted manner in the field as this gives real-life experience to students. He also advised to add YouTube videos as a supplement. Like speakers before him, Dr. Poole has challenges with students being able to meet on time as other things are taking priority. He suggests building on a project-based learning system. For example, Dr. Poole utilized weekly lab assignments from videos and supplemental reading and encouraged attendees to develop assignments “outside the box.”
The final speaker of this session was Dr. Michel Wattiaux. In response to transitioning to an online environment, he restructured a flip-course to be an online class. In his course redesign, he focused on setting the stage before starting class. This included posting three discussion prompts and allowing student to pick one prompt for class participation points. He believed that it brought about meaningful engagement with the paper but set the stage for a virtual discussion. Dr. Wattiaux would start class with a poll with simple questions as an icebreaker. He had a goal in mind to create a predictable pattern for virtual class section. Students would be grouped into breakout groups with a link for Google slides and documents with clear instructions. After working together for around 30 minutes, each group would then indicate what they wanted to share with the class. Dr. Wattiaux reiterated that time management was essential for this class and other online courses.
Overall, the main takeaways from this session were to be adaptable but also set realistic expectations. Get creative with your teaching style but make sure to remain relatable. Organization and time management are critical keys to success, but how you manage your classes is up to your personal style. Finally, be consistent! Figure out what works for you and your class and stick to it.
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Effects of rumen-protected choline on microbial
communities and hepatic function
By Miriam Snider
In high-producing dairy cattle, a period of negative energy balance occurs in the first few weeks of lactation. During the transition period, energy reserves in the forms of NEFA and amino acids are mobilized and used by the liver and muscle. This increased uptake by the liver may result in ketosis and fatty liver disease, negatively affecting animal health, production, and economics. Choline is a nutrient, sometimes classified as a “quasi vitamin” that supports cellular growth and metabolism. It is sometimes utilized as a nutritional strategy in its rumen protected form (RPC) as it is thought to potentially improve liver function. However, as the name implies, choline must be protected from the rumen as it is rapidly degraded by rumen microorganisms. In this section, researchers evaluated the use of choline on hepatic metabolism and on rumen microbe communities.
Arshad et al. from the University of Florida presented first, presenting their results on the effects of rumen-protected choline on metabolism during induction of fatty liver disease. Choline deficiency in monogastric animals and rodents leads to decreased synthesis of phosphatidylcholine, limiting lipoprotein synthesis that are required to export liver triacyglycerol (TAG). It was hypothesized that rumen protected choline (RPC) would reduce TAG and increase liver glycogen. Arshad et al. evaluated dose (0, 12.9, 25.8) and protection method (low and high concentration) of choline during negative nutrient balance on parameters such as hepatic TAG, hepatic glycogen, and plasma metabolites. One hundred ten dry pregnant cows were used in a random complete block design and held in a tie-stall facility and fed different doses of choline at different protection levels. Results showed that as days progressed, cows started to mobilize fatty acids. However, there was no effect of RPC, dose, or source of choline on plasma metabolites (BHBA, free fatty acids). Hepatic TAG was influenced by RPC and choline dosage; animals fed low concentrations of choline (on a wet and dry matter basis) showed a decrease in hepatic TAG content. Hepatic glycogen was affected by RPC, dose, and source of choline with glycogen levels increasing as the dose increased. These results indicate that choline can improve hepatic composition of cows that are in a negative nutrient balance; however, this is independent of change in plasma metabolite.
Using a dual-flow continuous culture system, Arce-Cordero et al. studied the effects of unprotected choline chloride on microbial community composition. Choline is usually fed in a protected form to prevent extensive ruminal degradation by microbes. However, research suggests that choline is not 100% protected and can still be degraded with the effects on the rumen microbial community remaining unknown. It was hypothesized that unprotected choline would alter rumen microbial populations and depended on dietary NDF. In this experiment, 8 fermenters were utilized in a duplicated 4 x 4 latin square design in a 2 x 2 factorial arrangement. Diets contained either 30% or 40% dietary NDF and contained either 0 or 1.9 g of choline ion/ kg DM. Samples were collected for VFAs and DNA sequencing. It was found that choline supplementation impacted the relative abundance of taxonomic order, with an increase
Selenomondales
and a decrease in
Fibrobacterales. Ruminocccaceae, Megasphaera,
and
Prevotella
increased in response to supplemented choline while
Succinivibrio
was only in greater abundance to choline when 30% NDF was available. These results indicate that unprotected choline alters rumen microbial populations that involved in carbohydrate fermentation as the abundance of starch utilizing bacteria increase.
Miriam Snider is a PhD candidate at the University of Vermont under Dr. Sabrina Greenwood. She earned her B.S. in Animal Science / Biology from Southeast Missouri State University and her M.S. from the University of Kentucky. Her current research explores forage and pasture quality/ energetics and its relationship with rumen fermentation and methane production in grassfed dairy cattle.
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Factors predicting pregnancy probability and pregnancy loss
By Iswarya Rajesh
The ability of a cow to become pregnant at optimum age and in a short interval after calving is important for the profitability of the dairy farm. Early identification of pregnancy helps to reduce the days open in case of nonpregnant cows, thereby breeding them. Researchers are increasingly interested in studying factors associated with the probability of predicting pregnancy.
Peixoto et al. carried out a study to characterize PAG and progesterone (P4) to predict twins and conception loss in high-risk pregnancy Holstein cows. Here they have classified cows as a healthy group (CON) and high-risk group (HR)/ twin pregnancy. Cows with a singleton pregnancy with the amniotic vesicle and heartbeat of at least 15mm and 60bpm respectively were classified as the control group. Slow heartbeat (<60bpm), small amniotic vesicle (<15mm), and extra membrane were classified as high-risk group cows. The cows with twin fetuses either in the same horn or different horns were classified as twin groups. Blood sampled in control and high risk/twin group at d 37, 44 and 51. The overall pregnancy loss after d 51 was high in high risk/twin group than the control group and cows that lost pregnancy had lower PAG concentration compared to pregnant cows. The threshold P4 concentration of 6.5ng/ml and 7.2ng/ml predicted the pregnancy loss and twins at d 37 post insemination, respectively. Whereas PAG was not able to generate pregnancy loss and twins at d 37.
In another study by Doyle et al. reported the effect of factors like feed treatment (low grass allowance (LGA), control, high concentrate (HC)), genetics (elite Holstein Friesian (GT), national average Holstein Friesian (NA), Jersey), fertility index (FI), milk index (MI) and milk yield (MY) that affects the pregnancy-associated glycoprotein (PAG) and pregnancy-specific protein B (PSPB) in the plasma of early lactating cows. They have collected blood to estimate the level of PAG and PSPB at d 23, 25 and 28 post insemination. The PAG fold change from d 23 to 25 post insemination was higher in cows fed with LGA than cows in the control and HC group. Between d 23 to 25, the PSPB were found to have higher fold change in cows with high fertility and >3+ parity. Likewise, a higher fold change was found in PSPB in cows with high GT between d 25 to 28 post insemination. However, the PSPB fold change in between d 25 to 28 post insemination was found to be lower in cows of high milk index, high milk yield.
Matias et al. conducted a study to predict the probability of pregnancy at first service (P/AI) based on the early lactation data and develop a model that predicts pregnancy in multiparous cows. Though they investigated various data from three weeks prepartum to the first evaluation of pregnancy. They considered only a few factors with a lower p-value of < 0.2 and included in the prediction. They developed a final model with the lowest AIC using logistic regression analysis and the probability of pregnancy predicted by ROC analysis. In conclusion, they found that the probability of pregnancy was influenced by season, displaced abomasum, lameness, subclinical endometritis, milk fat yield particularly the effect of mastitis, cyclic progesterone concentration at last PG of Double Ovysynch protocol, and body condition score was very high (≤0.001).
Iswarya Rajesh earned her degree in Veterinary Medicine from TANUVAS, India. Currently, she is a Master's student at the University of Alberta, supervised by Dr. Ambrose. Her work is on the Reproductive Physiology of dairy cows.
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Associations of selection indexes with phenotypic traits,
beef on dairy and future of genetics
By Kayla Alward
For the Monday Breeding and Genetics Block 3, discussions focused on linking various selection indexes with phenotypic traits and developing new associations, as well as exploring the future direction of dairy genetic selection and incorporating the ever-popular beef on dairy concept. The Dairy Wellness Profit (DWP$) trait, conformation traits, fertility traits and novel health traits for the Jersey breed are explored, economics of different beef on dairy strategies are compared and the session is wrapped up with a discussion on the future of dairy cattle selection in Canada.
Researchers from University of Pennsylvania and Zoetis evaluated over 2,000 animals from 5 large US herds to determine whether selection indexes predict differences in animal profitability in real world settings. DWP$ was evaluated against lifetime profit, which included a sum of income minus costs from the animal, including income over feed cost, calf value, salvage value, heifer raising costs and breeding costs. When animals were broken into quartiles by DWP$, they found an $811 difference in lifetime profit between the top and bottom quartile. The top quartile animals also produced 9,0004 kg more of energy corrected milk, had 202 day longer days in milk and had associations with number of live calves born and disease loss, indicating the ability of DWP$ values to predict differences in observed lifetime profit of animals.
Researchers from Guelph aimed to use statistical regression and principal component analysis to understand the association between 23 different conformational traits and the Canadian profit index (Pro$) and found that Canadian farmers do not need to consider all 23 conformation traits to achieve higher profits with their herds, but instead consider the Pro$ index. Data from over 9,000 bulls was considered, with body depth, dairy capacity, heel depth, chest width and rear udder attachment being the most correlated with Pro$ and rear legs rear view, bone quality, udder depth, rump angle and median suspensory ligament being least correlated. Together, body depth and heel depth contribute to 23% of the variation in Pro$. Overall, a clear difference in daughter profitability was noted between bulls, with highly profitable daughters coming from bulls with improved udder shape and size, similar profiles for dairy strength and rump and no difference form other bulls for feet and legs.
Researchers from the University of Florida outlined six different strategies for incorporating beef semen into a breeding program and showed the economic advantage (or disadvantage) for each. The program options included conventional semen, sexed semen and beef semen with regards to each lactation and based on number of services. The lowest economic return programs used conventional semen on all animals and saw a profit of $436 per milking cow per year. The most profitable program utilized mostly sexed semen on heifers with some beef semen and conventional semen on 4+ services, sexed semen on 1
st
and 2
nd
services in 1
st
lactation and conventional on 3+ services with older lactations receiving beef semen, resulting in a profit of $499 per milking cow per year.
Researchers from Guelph aimed to assess the potential bias that TAI might add to the estimated genetic parameters and breeding value of female fertility traits, through masking of lower fertility animals. Data from 4.4 million records was analyzed, with several records being kicked out due to a wide variety of breeding codes that were unclassifiable into a TAI or heat detection category. Standardized measures of recording breeding methods is required and methods to account for the bias of TAI are necessary, as evidenced by the re-ranking of bulls when analyzing heat detection vs. TAI records. Reduced variation in TAI records vs. heat detection was seen which further indicates that these animals are being controlled and fertility issues potentially masked.
Research from the CDCB evaluates the implementation of Jersey health evaluation traits. Holstein health traits were released in 2018, with a push for similar traits for Jerseys. When Jersey bulls ranked by these traits showed that the bottom bulls had a twice greater incidence rate for most negative health events with mastitis and metritis having a four-fold greater incidence rate in daughters from bottom bulls. A high correlation with health events and productive live and livability was also demonstrated and reliability estimates were increased compared to traditional progeny testing.
Finally, Semex collaborators discussed the future direction of the Canadian dairy industry. Emphasis was placed on increased technology use, more diverse producer goals leading to lower population inbreeding, increased utilization of biomarkers and a shift in Canadian dairy producer from developing show animals, to longer lasting commercial cows and genomics.
Kayla Alward is a PhD student at Virginia Tech under Dr. Rebecca Cockrum. She earned her B.S. in Animal Science and Dairy Science as well as M.S in Animal Science from the University of Georgia. Her current research explores the relationship between photoperiod, circadian rhythms and colostrum quality and reproduction.
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Lasers in cheese among highlights of Dairy Foods Sessions
By Tim Lott
On Wednesday, Dairy Foods Cheese presentations were open for live Q&A sessions at the 2020 ADSA Virtual Annual Meeting. The following provides concise summaries for each of the 12 presentations given by researchers across two sessions.
Haotian Zheng of NC State and Cal Poly presented on the impact of milk fat globule membrane materials on cheese made from reconstituted milk. The study addressed the issue that cheese quality made from reconstituted milk is usually not the same as the same cheese made from fresh milk. The study found that buttermilk concentrate is a functional ingredient that can improve recombined milk cheese quality citing ripening time is a critical factor.
Prateek Sharma of Utah State University gave two talks regarding laser techniques for studying salt diffusion in cheese matrices. One of these studies included a novel technique, laser-induced breakdown spectroscopy, for tracking salt diffusion.
Rodrigo Ibáñez of Pontificia Universidad Catolica de Chile and the Center for Dairy Research at UW-Madison gave a presentation regarding goat milk cheeses. Goat milks from late lactation may lead to cheeses with different quality including a decreased rate of proteolysis.
Hong Jiang from the Center for Dairy at UW-Madison summarized a comparison of curd washing and lactose standardization for the manufacture of Colby cheese. Lactose standardization produced good quality Colby cheeses with lower lactic acid content and softer texture.
Shaik Abdul Hussain from the National Dairy Research Institute in India presented the effect of processing variables on viscoelastic properties and textural attributes of heat-acid coagulated milk product paneer. The researchers determined that the correlation of processing parameters with texture and rheology gives better insights on controlling quality attributes of paneer.
Amaury Gèrard of the University of Liège (Belgium) answered the question: “What is the fate of
Listeria monocytogenes
in various types of Belgian artisanal cheeses?”
Luis Alberto Ibarra Sanchez of the University of Illinois discussed the efficacy of bioengineered nisin in combination with phage to eliminate
Listeria monocytogenes
in Queso Fresco. The researchers found that Nisin H27/31K combined with PlyP100 completely eliminated
L. mono
in all tested Queso Fresco samples.
Eduardo Cardoso-Gutiérrez of the Universidad Autónoma del Estado de México presented on the characteristics of cheeses from sheep milk. The defining characteristic of the milk was that sunflower seed silage was supplemented in the diets of the sheep in this study.
Ahmed Hammam of South Dakota State University explained the manufacture of culture-based acid curd using micellar casein concentrate (MCC). Significant results indicated that MCC can be utilized in the manufacture of culture-based acid curd.
Srirupa Sen from the University of Wisconsin presented on the manufacture of designer milk powder for recombined cheeses. The designer milk powder prepared could be rehydrated to 17.5% protein at high temperatures.
Yijing Gong from the University of Wisconsin evaluated the impact of lactose standardization and curd types on the properties of direct-salted Gouda cheese. Higher moisture and lower lactic acid content were some of the characteristics of the lactose standardized cheese.
Tim Lott is a PhD student at Cornell University. He conducts his research on milk quality under the advisement of Martin Wiedmann.
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Ano genital distance, a novel reproductive phenotype
By Iswarya Rajesh
Fertility is an important economic trait. Genetic selection of cows for fertility with the reproductive phenotype could be a strategy for sustainable production. Novel reproductive phenotypes like anogenital distance (AGD; the distance from the center of the anus to the base of the clitoris in dairy cows) were reported to have an inverse association with fertility had a better genetic variation in dairy cows. Various studies reported that excess androgen prenatally virilizes female genital organs and lengthens AGD, a sexually dimorphic trait (the AGD of the male is twice as that of female).
Carrelli et al. carried out a study to characterize AGD and its relationship to fertility in heifers. Holstein heifers (n=671) from 11 farms across Western Canada were characterized as either short (<114mm) or long (≥114mm) based on mean AGD of 114 mm. They reported that heifers with short AGD conceived sooner (p<0.01), requires fewer inseminations (p = 0.02) and had a greater pregnancy to artificial insemination (p = 0.01) than the heifers with long AGD.
Iswarya et al. from the University of Alberta studied the repeatability of AGD at different stages of the estrous cycle in lactating dairy cows. They synchronized 24 lactating Holstein cows, categorized as short (<127mm), and long AGD (≥127mm) and followed them for one complete estrous cycle from one ovulation to the subsequent ovulation. They determined the stages of the estrous cycle by ultrasound monitoring of ovaries for the presence and size of corpus luteum and P4 concentration in the blood sampled every other day for a complete estrous cycle. As well, AGD measurements from these cows every other day for a complete estrous cycle. They reported that there was no significant difference among the four different stages (proestrus, estrus, metestrus, diestrus) of the estrous cycle and the measurements were highly repeatable (0.99).
Previous studies from our lab reported that cows with short AGD had a better fertility outcome than longer AGD and had a moderate heritability. Besides, heritability, repeatability is important for a reproductive phenotype. If AGD is found to be highly repeatable at different stages of life, it could potentially be used in genetic selection of cows for fertility with other production and reproduction traits, that are currently being used, says Iswarya.
Iswarya Rajesh earned her degree in Veterinary Medicine from TANUVAS, India. Currently, she is a Master's student at the University of Alberta, supervised by Dr. Ambrose. Her work is on the Reproductive Physiology of dairy cows.
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Ruminant Nutrition-Gut physiology session summarized
By Bo Zhang
These topics of Ruminant Nutrition – Gut physiology Session on Jun 24
th
are mainly related to digestibility of lipids, fiber, and starch; rumen microbiota; microbial protein synthesis; and acetate formation pathway.
Vinyard et al. from the University of Florida developed an in vitro assay to determine lipids digestibility. This method can be further updated for measuring digestibility of rumen protected lipids in vitro. Focusing on starch digestibility in the rumen, Gleason et al. from Virginia Tech observed a relationship between in vitro and in situ methods and showed that feedstuff contents can influence the relationship. Schlau et al. found that washout portion from Dacron bag is fermented differently than what remains in the bag, suggesting the necessity to differentiate measured digestibility and true digestibility using in situ method. Total-tract fiber digestibility is related to diet composition, rumination time, rumen pH, cow size and lactation number, as showed by Cavallini et al.
Young et al. from the USDA tested the viability of using buccal swabs as a proxy of the rumen microbial contents, and found that buccal swabs samples of dairy cow prior to morning feeding are most similar to rumen solid samples. By analyzing composition of microbiota, Wang et al. from Heilongjiang Bayi Agricultural University identified alternations of ruminal and fecal microbial communities in dairy cows during ketosis. Pitta et al. from the University of Pennsylvania identified differences in ruminal microbial species and methanogenesis pathways of low and high methane-yield dairy cows, which can explain why high methane-yield dairy cow produce more methane.
Rumen microbes represent the largest and cheapest source of protein for cattle. Mitchell et al. from The Ohio State University found that supplementing branched chain volatile fatty acids improved efficiency of microbial protein synthesis and NDF degradation in vitro, suggesting a potential strategy to increase both microbial protein and nitrogen efficiency.
Acetate is one of most important volatile fatty acids to cattle. Zhang et al. from UC Davis proposed that bacteria can a new pathway to form acetate and produce energy (ATP), which involves two enzymes succinyl-CoA acetate:CoA transferase and succinyl-CoA synthetase. About 1/5 of bacteria that form acetate encode this pathway. The finding can guide efforts to change acetate production in the rumen.
Bo Zhang is a PhD student in the Department of Animal Science at UC Davis. He earned his M.S. from the University of Chinese Academy of Sciences. Under the guidance of Dr. Timothy Hackmann, he is working on how rumen microbes ferment feed and produce protein digested by cattle.
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Research insights from Wednesday Poster Session-Dairy foods
By Shayanti Minj
In the last day of the ADSA’2020 virtual meeting, there were 15 research posters presented from the Dairy Foods division. The presentations were available in a pre-recorded version and a live chat session was conducted in the afternoon to connect the researchers with the audience directly and answer their questions.
The first research was from Oregon State University. The authors determined the variation in the cheese microbial population, from daily monitoring of the cheese production facilities. The results displayed a diverse microbial community that varied between days and between facilities. This illustrates the importance of repeated sampling and suggests sampling strategies that can be applied for studying cheese microbiome in cheese processing plants.
The second work was based on the preservation of cheese, where the researchers from Cornell University implied lactose oxidase in a Hispanic-American variety of cheese (queso fresco), to inhibit one of the pathogenic bacteria,
Listeria monocytogenes
. The results show an effective inhibition in the growth of the pathogen, which remained below the detection limit. This offers a way to use a clean label ingredient beyond traditional preservatives.
Talking about clean label ingredients, researchers from Kansas State University transformed a whey protein to fibrils through heating that can be applied as a clean label ingredient for industrial applications. Their work was to elucidate the effect of static and stirred heat treatment on the native whey protein fibrils. Overall, the results demonstrated a higher degree of fibril aggregation in static heating as compared to stirred type, which tells us that through stirred heating, the time to produce the whey protein fibrils can potentially be reduced.
Defects in cheese due to late gas formation can lead to severe economic losses in dairy industries. The researchers from the University of Wisconsin-Madison presented their work on the association of biogenic amines (BA) in causing defects like slits and cracks in cheeses. The results showed different levels and types of BA, corresponding to the pH values. Hence, this suggests that BA can be one of the major compounds responsible for the undesirable late-gas formation in cheeses leading to cracks and slits.
Numerous opportunities for Salmonella survival or contamination during the manufacture of dried milk can pose a possible food safety risk. A work from Fort Valley State University describing the ability of the Salmonella to survive in powdered goat milk room and refrigerated storage conditions was presented. The results showed that the Salmonella counts in the spiked powder products decreased gradually throughout the storage period, and the survival was greater at 4°C storage as compared to storage at 25°C.
A study from the Institute of Nutrition and Functional Foods, Canada, was presented regarding analyzing the effect of ultra-pressure homogenization and pH on buttermilk, with the intent to improve its functionality for application in dairy products. The results demonstrated that the treatment of 300MPa pressure combined with a pH of 10.5 was effective in modifying the buttermilk particularly targeting the casein micelle portion. This indicated the possibility for the valorization of buttermilk in dairy products, by modifying its constituents.
Insights on understanding the effect of several heat treatments on destroying the antibiotics in milk were shared by researchers from Uruguay. Their work was to study the effect of temperature and time on the heat- inactivation of 15 β-lactam antibiotics and 3 tetracyclines in milk. Thermal treatment of 63°C/30min degraded less than 25% of the 11 antibiotics out of 18, whereas treatment of 80°C/60min degraded greater than 95% of the antibiotics. This knowledge can further be used to develop tools and strategies to minimize the food safety risk of antibiotics.
Researchers from the Federal University of Goiás, Brazil, shared consumer acceptability of whey-buttermilk fermented beverage with added gabiroba (
Campomanesia xanthocarpa
). They prepared thirteen formulations, each with different ingredient concentrations, and conducted the sensory evaluation. Results showed that all formulations were well accepted by the consumers with scores between 6 (like slightly) to 8 (like very much), which gives an overview of the consumer preference and acceptance of fermented beverages prepared from whey and buttermilk.
The addition of probiotics in different food matrices and maintaining its viability can be challenging from a technological point of view. Hence, researchers from South Dakota State University presented a study that focused on the application of probiotics in emulsion dairy food matrices, where probiotics in encapsulated form were added into salted and unsalted butter, and the stability of the organisms was determined. The results showed that the probiotics counts were maintained in both salted and unsalted butter which provides a proof of concept for the potential to develop a probiotic butter with desirable probiotic counts.
Another study from Louisiana State University was presented that involved developing camel milk probiotic drinkable yogurt and evaluating the effect of monk fruit sweetener on the stability of the organisms. The results showed no reduction in the counts with an increase in the monk sweetener, however, there was a significant decrease in the counts during storage of the product at 4°C, which is possibly due to the presence of antimicrobial compounds in the camel milk, as explained by the authors.
A study from South Dakota State University was presented regarding determining the types of Bacillus endospores present in milk protein concentrates (MPC) and milk protein isolates (MPI). The results from MALDI-TOF revealed
Bacillus licheniformis
to be the predominant spore-forming bacteria in both MPC and MPI. Further, the findings can be utilized to develop design strategies to control endospores in dried milk and powders.
Besides, milk powders, fluid milk can also be affected by spore-forming bacteria during storage at low-temperature conditions. A study from Cornell University demonstrating the effect of higher HTST pasteurization on the spore-forming bacteria was presented. From the results, it was suggested that 75°C was the optimal temperature for HTST pasteurization, which required the least energy utilization with no sensory changes.
Another interesting study from Cornell University was presented regarding a potential application of food-grade microbes in a matrix followed by HPP (high-pressure processing) which can inhibit the growth of undesirable bacteria in foods. The cultures were encapsulated in the cocoa butter matrix through homogenization before applying HPP. The resultant product was a cocoa butter encapsulated freeze-dried culture. Further studies related to the application of the dried encapsulated cultures to a high moisture food matrix are in progress.
Researchers from Oregon State University presented their work on evaluating the effect of conventional dairy farming practices on the raw milk microbiome. The results demonstrated higher coliforms and anaerobic bacteria in bulk tank milk samples produced from conventional farm techniques as compared to an organic one, with no difference between bacterial counts and bedding material types. Similarly, the sequencing results showed a variation in the counts and types of bacteria withing farming sites, groups, and between conventional and organic farming types.
The presentation was ended with the last presenter from Oregon State University, who provided a survey from the current industrial practices to rework dairy products. The survey was conducted through phone and an in-person meetings with six dairy processors. The results showed that the main motivation for fluid milk processors to rework their product is mostly due to standardization issues or mislabeling, and for dairy powder processors, it is mainly due to microbial contamination. This certainly implies that reworking can help to reduce waste and economic losses, however, it is important to further investigate the effect of reworking on the quality of the products.
I am currently a Ph.D. candidate at the Dairy and Food Science Department of South Dakota State University, under the supervision of Dr. Sanjeev Anand. I am working on developing a novel bioactive ingredient formulation utilizing whey protein hydrolysates and encapsulated probiotics.
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Undergraduate students present on dairy production,
dairy foods, original research
By Kayla Alward
Members of the Student Affiliate Division (SAD) presented talks and posters on a variety of topics for the Dairy Production, Dairy Foods and Original Research competitions. In the area of dairy foods, presentations focused on adding value to the dairy products market and improving product quality, while dairy production presentations focused on management opportunities for greater success on the farm. The original research oral competition covered topics in milk quality and testing, calf health, heifer development and nutrition. Finally, the original research poster competition included topics in nutrition, mastitis, reproduction, calf health and dairy foods.
DeMers from the Pennsylvania State University explored camel milk as a novel product to the dairy market. A previous study (Cardoso) has shown that lactose intolerant patients have significantly decreased reactions when drinking camel milk compared to cow milk and that camel milk may provide health benefits to diabetics by increasing blood sugar and insulin sensitivity. With a similar flavor profile and compositional makeup to cow milk, camel milk may be a viable novel product for the dairy market. Likewise, Crews from the University of Georgia explored options for improving fluid milk utilization within the dairy market. Three recommendations were made to achieve this: 1) increase refined milk options such as A2, ultra-filtered and ultra-pasteurized to create a product that stands out, 2) improve packaging techniques through style and size by creating more consumer friendly packages and 3) explore more value added products such as diet and recovery, lactose free and flavor added products. Adams from the University of Kentucky evaluated pasteurization techniques and subsequent impact on the milk product and flavor profile to consumers. Of the two most popular pasteurization methods (high temperature, short time or HTST and ultra-high temperature or UHT), research has shown a breakdown of beta lactoglobulin in UHT as well as increased number of free fatty acids indicating a higher level of lipolysis. Sensory evaluations indicate that generally, HTST rated better than UHT to consumers.
In the Dairy Production category, McGehee from Virginia Tech explored the advantages of utilizing gene sequencing on embryos for producers. Unlike either progeny testing or genomic testing, gene sequencing embryos allows for the earliest evaluation of an animals’ genetic status. While it is coupled with a decreased pregnancy rate and the possibility of compromising the embryo, it allows the farm to prioritize embryos and have reliable information to increase genetic progress of the herd faster than other techniques. Rauton from the University of Georgia analyzed the proposed benefits of altering photoperiod for the prepartum dairy cow. In short day animals (8 h light + 16 h dark) prolactin concentrations were lower, however milk yield was greater during the next lactation. Phase shifting lighting also demonstrated more attenuated body temperatures and melatonin production, demonstrating a potential to improve transition cow management. Bitter from Louisiana State University presented pain management options for disbudding calves. Her summary showed that pain persists up to 180 minutes after caustic paste application and calves were most comfortable when they received an NSAID as well as a local anesthetic (cornual nerve block). In addition, a sedative was recommended for these animals to improve animal welfare. The final presentation by Mosher from the University of Tennessee focused on management practices to prevent sub-acute ruminal acidosis (SARA). As a costly disease, prevention vs. treatment was advocated by ensuring adequate forage to grain ratio, optimal non-fiber carbohydrate percentage and proper length forages to promote chewing and saliva production to aid in buffering the rumen. While it can be controlled with buffers, ration issues should be addressed first.
In the Original Research category, Wood from Cornell evaluated mid-infrared spectroscopy (MIR) for milk urea nitrogen (MUN). While MIR has advantages over other methods including speed, cost, minimal training and number of samples able to be run, she also found that MIR machines tend to overestimate MUN at lower values and underestimate at higher values, with a great deal of variation in values from the same samples processed at different labs. Hillis from the University of Georgia explored pulse oximetry, lactate levels and lung ultrasonography as a means of predicting respiratory illness in calves. While the trial saw only one respiratory illness case, the methods were evaluated for usability. The lactate meter is easiest to use, but relatively cost prohibitive, while the pulse oximeter is difficult to use due to placement on a calf. Ultrasonography is the most reliable measure for finding respiratory illness but requires skill that may be impractical for most producers. Oduyela from Virginia Tech explored the impact of exogenous estrogen on mammary collagen distribution in Holstein heifers and found no effect when heifers received an implant for only 2 weeks. However, collagen deposition did vary by location, with more collagen present around the gland cistern vs. the mammary fat pad. Abou-Rjelleh from Michigan State found that animals supplemented with a live yeast during a fermentable starch challenge did not experience a depression in fat content and yield, while a control group receiving no yeast experienced a depression in fat content and yield post fermentable starch challenge.
In the Original Research Poster category, Xu from University of Missouri analyzed the foaming and baking properties of spray-dried ingredient from whey protein and pectin complexes. His results show that using whey protein with a pectin complex is significantly more stable compared to egg white protein and can drastically improve properties of cake made with just whey protein. Sgambatti from the Ohio State University found that pre-weaned calves fed a high starch, low starch or high starch with higher fat diet showed no differences in body weight, whither height, starter intake or fecal and respiratory scores through 9 weeks of age. This indicates more purchasing flexibility for farmers without compromising growth. Hist, also from the Ohio State University evaluated the effect of intramammary infections on Jersey colostrum quality. She found no differences in antibody concentrations between uninfected and infected animals, however the Brix score was higher in uninfected quarters for multiparous cows compared to infected, but this was not seen with primiparous cows. Crumel from North Carolina Agricultural and Technical State University tested the use of Yucca schidigera as an additive to reduce green house gases in vitro. At an inclusion rate of 2 g/head/day, methane, CO
2
, ammonia and hydrogen sulfite were drastically decreased without having an effect on true or apparent dry matter digestibility, efficiency of microbial production, microbial mass or short chain fatty acids. Hollandsworth from University of Florida analyzed sodium lignosulfonate as a potential preservative for wet brewers grains (WBG). While sodium lignosulfonate preserved sugars and kept NDF the lowest, there were high dry matter losses and the conclusion was that propionic acid is still the best preservative. Hamilton from the Pennsylvania State University evaluated uterine dextrose infusions as a treatment for clinical metritis against traditional treatments of ceftiofur. Dextrose infusions showed a similar cure rate to ceftiofur treatment, but animals treated with ceftiofur produced more milk than dextrose treated animals post-treatment. Finally, Uzee from Louisiana State University evaluated insulin sensitivity in calves at varying ages and found that calves aged 3 weeks were the most insulin sensitive, requiring only 15 mU/kg body weight to illicit a response, compared to animals 9 weeks old which required more than 30 mU/kg body weight. He also validated an on farm test developed for use in horses to assess glucose response in young dairy calves.
Placings for these competitions were announced Tuesday evening.
Dairy Production
: 1
st
- C. McGehee (Virginia Tech), 2
nd
- M. Mosher (University of Tennessee), 3
rd
- A. Rauton (University of Georgia.
Dairy Foods
: 1
st
- G.M. DeMers (The Pennsylvania State University), 2
nd
- A. Crews (University of Georgia), 3
rd
- L.M. Adams (University of Kentucky).
Original Research
: 1
st
- M.K. Hillis (University of Georgia), 2
nd
- E.M. Wood (Cornell University), 3
rd
- U. Abou-Rjelleha (Michigan State University).
Original Research Poster
: 1
st
- J. Xu (University of Missouri), 2
nd
- J. Hamilton (The Pennsylvania State University), 3
rd
- E.M. Hist (The Ohio State University).
Kayla Alward is a PhD student at Virginia Tech under Dr. Rebecca Cockrum. She earned her B.S. in Animal Science and Dairy Science as well as M.S in Animal Science from the University of Georgia. Her current research explores the relationship between photoperiod, circadian rhythms and colostrum quality and reproduction.
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Research insights from Tuesday’s oral session on Dairy Foods:
Dairy Products (Block 2)
By Shayanti Minj
There were six researchers from different universities that presented a very significant piece of their work in a pre-recorded version. Following, a live streaming session was conducted to directly connect the speakers with the audience and answer their questions. Dr. Sanjeev Anand from South Dakota State University was the chair of the session.
The first presenter was C.Nyuydze from South Dakota State University. Her work was based on determining the effects of soy-lecithin on the formation and stability of ultrasound emulsions when added at different concentrations. Beverages with different concentrations of soy-lecithin were prepared and emulsified through ultrasonication under different intensities. Further, the beverages were stored at refrigeration temperature to study the stability of the soy-lecithin. The results showed emulsions with a mean particle size of 310-748nm, whereas aggregated particles were observed in samples without lecithin. Overall, combining ultrasonication treatment and soy-lecithin led to strong gel with shear thinning behavior. Hence, the authors suggest that ultrasound can be applied to whey-based emulsifiers to characterize its functionality.
The second presenter was A. Bienvenue, from US Dairy Export Council, VA. She presented her work on comparing the performance of Skim milk powders originated from various regions. With respect to composition, all the samples met CODEX requirements, however minimal difference in pH, acidity, and functionality were observed. Heat coagulation time varied and the samples from New Zealand had a slight yellow color. The difference in the microbial counts was observed between the samples and varied among suppliers. The samples were stable under UHT (ultra-high temperature), however under EM (evaporated milk), gelling was observed in one sample. Overall, minor changes were observed during storage. From the results, the authors suggest that the difference in the performance can vary depending on the supplier and not specific countries.
The third presentation was about the application of a novel approach, Electrical Resistance Tomography (ERT) for monitoring the rehydration characteristics of dairy powders with high protein content, presented by K.S Babu from Kansas State University, KS. In this study, a method was developed to analyze milk protein concentrates (MPC) through ERT using two configurations, followed by validation. The results showed that with an increase in the dissolution rate, the release of ions and protein from the samples increased, and, with the increase in the protein release, there was a decrease in the conductivity and solubility of the samples. Overall, the results varied between the configurations and suggest that ERT can be one of the economical methods to characterize the functional behavior of dairy protein powders.
The next presenter was from Sakarya University, Turkey, who presented work on developing cornichon pickles using acid whey from Greek-style yogurt. The work was focused on investigating the suitability of acid whey in the production of pickles by monitoring the changes in the texture, microbial, visual, and sensory properties. The results showed that pickles prepared through pasteurization using acid whey had increased pH as compared to pasteurized pickles with added vinegar. Microbial species (lactococci) were found higher in pasteurized and fermented pickles manufactured with acid whey during storage. Overall, these findings suggest that acid-whey can act as a good brine media for pickles.
The last presenter was Dr. Bohdan Luhovyy from Mount Saint Vincent University, Nova Scotia, who delivered two presentations. His first presentation outlook was regarding determining the effect of total milk protein (TMP) and its fractions (casein (CN) and whey (WP)) on blood glucose (BG) and insulin in rats. The research was done on six male Wistar Han rats and they were treated with 350 mg/ 3mL of either TMP or CN or WP or glucose. Results showed a significant effect of treatment over time. Overall, the findings show that all the protein treatments showed an increase in the insulin levels in a similar pattern as compared to the one treated with glucose alone.
His second study was regarding analyzing the sensory perception of milk protein fractions when applied to different liquid and solid food matrices. Whey protein isolates extracted from ion-exchange (WPI-IE) and membrane filtration (WPI-MF), glycomacropeptide (GMP), micellar casein (CN), and milk protein isolate (MPI) were tested either by adding into milk or water or in a freeze-dried whole milk form, through 9-point Hedonic scale. The results displayed that the overall acceptability varied among the treatments and suggest that the addition of MPF in food matrices has the ability to affect the taste of the final product and can potentially be improved with the addition of sweeteners or flavoring compounds.
I am currently a Ph.D. candidate at the Dairy and Food Science Department of South Dakota State University, under the supervision of Dr. Sanjeev Anand. I am working on developing a novel bioactive ingredient formulation utilizing whey protein hydrolysates and encapsulated probiotics.
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