Dairy Science Digest

When the thermostat spikes, and temperature stress is high on the herd, what lasting effects are made? A data set that began several years back continues to grow in strength suggesting that summer calving harms in irreversible ways. This paper specifically focuses in on the calf developing in utero, incubated like a crock pot inside the dry cow. Maverick Guenther, conducted a studied with the oversight of Dr. Laporta in WI to specifically measure the impact of in-utero heat stress conditions on colostrum absorption to help explain the decreased calf performance parameters previously seen and ultimate reduction in milk production years later. Listen in today to learn how colostrum absorption is impacted and possible ways to improve the situation. Topics of discussion 1:40      Introduction of Maverick Guenther 3:42      Experimental design; calves heat stressed 4:43      Background IgG transfer from dam into offspring– Apparent Efficiency of Absorption (AEA) 8:04       Long term effects of heat stress 10:41     Microscopic observations of intestinal lining in addition to cellular death measurements 12:01    Acceleration of gut closure might be due to Cellular death   12:58     Does heat stress impact colostrum? 14:38     A second meal of colostrum might help 15:47     Changes in gene expression 16:46     Deeper explanation of “FC receptor” changed due to HS in utero 18:39     What is the source of the FC receptor   20:24     What does colostrum absorption look like for mild heat stress and primiparous animals                22:38     What are research next steps – rescue feeding vs prevention        23:14     Stress response, such as SCC impact on colostrum absorption                     25:10     What do you want boots on the ground dairymen to know from your research? 26:19     Ideal colostrum brix reading Featured Article: Effect of in utero heat stress on neonatal small intestinal cell turnover, and markers associated with barrier function and IgG transport in newborn dairy heifers. Past relevant episodes: 2024: DSD 5.5 | Avoid generations of production losses 2020: DSD 1.7 | Calves born to heat stressed dams programming for failure 2025: DSD 6.2 | Bump colostrum quality with ease 2026: DSD 7.7 | Manipulating absorption of colostrum #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #heatstress; #AEA; #dairy; #colostrum; #calf; #survival; #FCreceptor; #absorption; #IgG; #dairysciencedigest; #ReaganBluel

It’s well accepted that management decisions during the first few weeks of life, can impact the long-term trajectory of success. Easy examples of this fact are colostrum management, plane of nutrition and vaccinations just to name a few. One can typically expect an increase in average daily gain, will return in the bulk tank 2 years later. Research on social housing over the years has shown an increased rate of gain during the milk phase, but hasn’t captured the implications later in life. First calf heifers transitioning into the milk string tend to be skittish, reluctant to enter the feed alley and fight with the boss cow. Through this transition, her size matters but also her ability to remain resilient in consistently tolerating the social attributes of the milk string. Dr. Emily Miller-Cushon, and her team of researchers from the University of FL in Gainesville really wanted to measure the impact of housing type on long-term effects, therefore they made the investment to compare individual, paired or group housing to determine if one housing type would dramatically impact her first lactation success. Listen in today to learn how social housing could improve your profits through increased survival and milk yields through social resilience. Topics of discussion 1:49      Introduction of Dr. Emily Miller-Cushon 2:47      Background overview of social housing 4:52      Project objectives and study design; individual, paired or group housed calves 6:04       What’s the best way to begin implementing paired housing on farm? 8:26       Managing the first two weeks of life for large groups 9:30      What’s the ideal age range in paired and groups. 10:24     Diets fed 11:48     Breeding aged culling rate 12:41     Cull risk timing (Figure 1) 14:01     ADG did not explain the milk yield change (Figure 4) 18:43     Cross sucking and mammary health 22:11     Longterm effects of paired housing, survival through lactation (Figure 2) 24:15     Milk production, first 5 weeks (Figure 3) 26:42     Disproportionately culled high producing, individually housed animals 28:04     What do you want boots on the ground dairymen to know from your research? Featured Article: Long-term effects of dairy calf social housing on first lactation survival and milk yield #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #groupedhousing; #pairedhousing; #dairy; #calf; #ADG; #survival; #resilence; #firstlactation; #dairysciencedigest; #ReaganBluel

Much research has focused around the transition period. Recent findings suggest feeding oleic and palmitic fatty acids could aid in improving the energy balance of the cow, but why? Dr. Andres Contreras and his team of researchers conducted benchtop science, studying fat tissue to best understand the mode of action documented in this month’s featured article. The mitochondria is the powerhouse organelle in the cell which determines the energy status for the cow. If running efficiently, this ‘cellular engine’ will generate a substantial amount of energy, or ATP. However, when operating inefficiently, due likely to damage from oxidative stress, the organelle will generate less energy, resulting in the cow mobilizing more fat stores to fuel milk production. We all know, if the negative energy balance “spiral” begins – the cow is going to struggle through the transition period which has lasting implications on the entire lactation. Listen in today to learn about how energy production in early lactation could be impacted by your feeding program. Topics of discussion 1:45      Introduction of Dr. Andres Contreras 3:00      What do you want ‘boots on the ground’ dairymen to know about your project  4:49      Mitochondrial activity   6:04       Objective of the study, what happens to mitochondria when challenged and when subject to oxidative stress.   6:55       Two possible paths for the mitochondria in the first week of lactation. 8:04       When cows start to mobilize fats – mitochondria dysfunction begins 9:37      Excessive Lipolysis results in inflammation response 10:15    Treatment design 11:04     How did you test the effect of Oleic and Palmitic Fatty acids on the mitochondria? 11:47     Impact of Oleic Acid on mitochondria function 12:50    Increased respiration rates of the mitochondria, and why that matters.   14:08     ATP increase - The importance of the first 3 days in milk 15:53     How does FA concentrations impact the Redox reaction (Antioxidants : Oxidants) 18:10     If you have a cohort of over conditioned cows, would OA and PA help? Why? 20:43     Day 3 NEFA impact on first service conception rate Featured Article: Oleic Acid Supports Mitochondrial Function During Lipolytic and Pro-Oxidant Challenges in Bovine Adipocytes Day 3 NEFA article: Concentrations of nonesterified fatty acids and glucose in blood of periparturient dairy cows are indicative of pregnancy success at first insemination #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #oleic; #transitiondairy; #mitochondria; #ATP; #liposis; #NEFA; #dairysciencedigest; #ReaganBluel

Arguably the most important first step in the life of any calf is successful establishment of passive immunity through colostrum management. This key touchpoint ensures easy newborn calf management for weeks in the future and improved pay price for your bull calves. Colostrum replacers occasionally need fed, for a variety of reasons. Understanding the key details of absorption, allows colostrum replacer manufacturers to optimize their product and therefore your success. How does dilution impact the absorption of the colostrum replacer, based on the rate of abomasal emptying? Does this impact the calf’s IgG absorption and ultimately success of passive transfer? Listen in to Dr. Alberto Lopez has he describes the results of his recently released research and observations from the field. Topics of discussion 1:43      Introduction of Dr. Alberto Lopez 2:39      Project design/treatments   3:08      150 IgG replacer used 4:55      Different CR products on the market  5:23      Osmolarity in colostrum 6:44      Maternal colostrum enhancement – impact on osmolarity 8:17      Path of colostrum once it leaves the tube 8:33      High osmolarity takes longer to feed, and digest 9:58      Should producers measure osmolarity?   11:17    Measuring / tracking successful transfer of passive immunity (STPI) 13:29    Calf buyer pay price 15:03    How did dilution impact IgG absorption 16:06    IgG upper limit maxing out absorption 17:27    Abomasal emptying 22:23    No difference in IgG absorption in differing dilution 27:35    What do you want ‘boots on the ground’ dairymen to know about your project  Featured Article: The effect of dilution of colostrum replacer on IgG absorption, abomasal emptying rate, and gastrointestinal permeability in newborn Holstein calves #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #IgG; #colostrum; #colostrumreplacer; #colostrumenhancement; #calf; #STPI; #dairysciencedigest; #ReaganBluel  

Opportunistic Grazing is a term used to maximize forage grazed on marginal land for heifer development. Research work completed in Wisconsin nearly a decade ago and recently published defined the differences between heifers reared on pasture for 6 months annually vs those housed in confinement year-round. Heifer development is the second most expensive portion of the dairy enterprise, and feed going into your replacements is the easiest metric to change. Simply by rotating the females between pastures every 2-4 days during optimum grazing conditions, this data suggests a return of nearly 2700 lbs milk during her first lactation when compared to the ‘couch potato’ counterpart on TMR. Listen in today to learn about what observations to expect, how to be responsive and nimble to weather while decreasing cost of production. Additionally, researchers Ken Kalscheur and Carlos Camisa Nova provides a sneak peek at future research being conducted to better understand what is changing in the heifer to improve first lactation performance. Topics of discussion 1:57      Introduction of Dr. Kalscheur and Carlos Camisa Nova 3:07      Project design/details/background 6:30      How was the pasture measured 7:46      Discussion of supplementation strategies 9:04      TMR composition for 1.8 ADG goal 10:03     Bodyweight difference after first grazing season 12:24     Supplementation strategy to bred heifers, during a drought year 14:59    Feed costs – pasture vs TMR, reduction of 35%   17:21     Repro effect of pasture vs confinement 18:59    First lactation performance of pasture based heifer development 20:02     Impact on Dry matter intake during first lactation 22:23     Follow up project, in progress, to assess possible metabolic differences 25:40     Impact of an activity difference in the two styles of rearing animals 27:57     What do you want ‘boots on the ground’ dairymen to know about your project  Featured Article: Growth and lactation performance from dairy heifers raised in confinement or on pasture #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #pasture; #replacement; #heiferdevelopment; #milk; #dmi; #active; #dairysciencedigest; #ReaganBluel