Dairy Science Digest

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 Nova3:07 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 animals27:57 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

It’s always exciting to watch a group of replacement heifers develop and anticipate their performance in the milking string as the top genetics of your herd. There is just about nothing more devastating than freshening them in to find mastitis or even worse, a blind quarter. When a first calf heifer calves in with a high somatic cell count she is more likely to maintain the high count, and more likely to be culled. Heifer mastitis, or intramammary infection (IMI), is a common affliction yet we know very little about what stage of production it occurs and how to best diagnosis the root of the problem. Pamela Adkins, DVM at the University of Missouri worked with a team to capture culture samples from a variety of stages of heifer development to fabricate standard protocols for sample collection and help producers better understand how to circumvent this disease cycle for their herd. Listen in to learn how to improve heifer development and limit the tragedy of damaged replacements. Topics of discussion 1:51 Introduction of Dr. Pamela Adkins2:26 Why is this topic important 4:17 Establishing standard sampling procedures 5:11 Cisternal puncturing 7:43 Comparison of sample collection 8:37 Grouping to determine when IMI begins in heifers 10:27 Causes and severity of infections 11:53 Feeding raw milk to hutch heifers12:51 Normal microflora vs mastitis causing 15:36 If you have a heifer mastitis problem, what’s the next steps 17:21 What’s the best way to collect a sample? 18:44 Where to send aseptic samples 19:54 To freeze or not to freeze 21:48 Why were gestating heifers 8x as likely to have IMI? 23:05 What do you want “boots on the ground” dairymen to learn from this project? Featured Article: Evaluation of intramammary infection status in dairy heifers using cisternal and teat end sampling techniques #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #HSCC; #heifer; #milksampling; #culture; #mastitis; #IMI; #infection; #dairysciencedigest; #ReaganBluel

For decades, ethanol production has generated affordable biproducts to feed. A new distilling method has generated a product with ~50% protein. Dr. Billy Brown, assistant professor of dairy science at Kansas State, wanted to understand how this feed would compare to soybean meal in a starter grain. To test this he developed rations substituting soybean meal 1:1. Graduate student Rachel Skinner measured intake, growth, effiency and metabolic and digestive parameters to best understand if this product would work in post weaning phase of production. Topics of discussion 1:19 Introduction of Dr. Billy Brooks3:18 Nutrient composition of high pro corn coproduct 5:14 Study Design6:33 Limiting Amino Acids 7:53 Age of calves 8:34 Starter Digestibility 10:40 Average Daily Gain (ADG)13:30 Insulin measurements 15:36 CP concentrations for the rations16:25 Heat Stress17:58 Dry matter intake and feed efficiency 19:05 Pelleting feasibility/stability 20:05 Yeast bodies – Impact, source of and future research efforts22:53 What do you want Boots on the Ground dairy producers to gain from the project? 23:32 Breakeven analysisFeatured Article: Effects of a high-protein corn coproduct as a replacement for soybean meal in calf starter feed in the postweaning period #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #HPCC; #dairycalves; #DDGS; # Protomax; #dairysciencedigest; #ReaganBluel; #Rachel Skinner

DSD 6.3 | Big Picture Management Decisions Matter Timeless dairy management decisions, such as voluntary waiting period & days dry, have recently been the topic of interest across the globe. Scrutiny to illuminate the ideal to maximize productive life has left the industry questioning convention. Michael Overton, DVM at Zoetis worked with co-author Steve Eicker to tease out the answers to these questions from a a massive dataset of 109,000 cows across 60 herds nationwide. This retrospective, observational research project was recently published in the Journal of Dairy Science titled, “Associations between days open and dry period length versus milk production, replacement, and fertility in the subsequent lactation in Holstein dairy cows”. All dairymen should pause to determine the unintended consequences of their management decisions on optimal performance and ultimately the economic success of the herd. Listen in to learn ways to apply concepts from this project to your operation. Topics of discussion 1:33 Introduction of Dr. Overton 2:54 Difference between association vs causation 4:28 Description of data set 4:51 Genomic testing, background 6:31 Advising herds on selection indices DWP$10:02 Different measurements collected – carry over impact of days dry and days open11:50 Figure 4: Impact of previous days open and previous days dry on cumulative milk 14:04 Risk of replacement and impact of mastitis18:05 How many sins is a dairyman willing to forgive? 19:46 What does your data say for optimal VWP 22:27 Twin events or sex of calf 24:59 Figure 7: Risk of pregnancy 28:46 What do you want Boots on the Ground dairy producers to gain from the project? Featured Article: Associations between days open and dry period length versus milk production, replacement, and fertility in the subsequent lactation in Holstein dairy cows #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #daysdry; #milk; #previousdaysopen; #VWP; #daysdry; #DWP$; #Zoetis; #dairysciencedigest; #ReaganBluel;

DSD 6.1 | Management to create the invisible cow If you pause and think about a list of cows – chances are the list that pops into mind is a group of troublemakers that didn’t breed back or need another round of treatment or are on this week’s cull list. What if you could create a herd of unmemorable cows – ones who just do their job; make milk, breed back, no mastitis – the "Invisible Cow". Dr. Krogstad’s research program’s goal is to create more invisible cows; ones you only see at calving, breeding and dry off. This month he shares with us a dataset analyzed for associations of hyperketonemia (HYK) with body condition, milk production, pregnancy loss, mastitis and ultimately culling. It turns out that the timing of lipolysis determines if it is healthy or harmful and ultimately has a big impact on her success through transition. It all boils down to are the free fatty acids being mobilized to fuel early lactation being completely oxidized or partially oxidized? Listen in to learn more about our featured article: Associations of Body Condition Score, Body Condition Score Change, and Hyperketonemia with Mastitis, Reproduction, and Milk Production Topics of discussion 1:40 Introduction of Kirby Krogstad2:39 Definition of hyperketonemia (HYK)4:22 Frequency of HYK 5:16 Milk yield decrease due to hyperketonemia 7:36 Figure 3: Prepartum BCS by lactation9:39 Ideal range of prepartum BCS 10:17 Impact of BCS loss on pregnancy loss 12:04 What’s the biology behind the pregnancy losses? 13:58 How does hyperketonemia impact odds risk mastitis? 14:44 Cellular rationale behind increased mastitis risk16:36 Figure 5: Health status impact on milk yield18:16 “Healthy” Lipolysis 18:58 Were cows with high BHB treated? 19:43 Week one vs week two – Timing of Lipolysis 20:40 Healthy Lipolysis generates the invisible cow 22:11 Can you suppress inflammation to improve transition? 23:08 Lipolysis in week one 25:24 Culling association to hyperketonemia 26:15 BCS association to culling 27:27 Impact of stable BCS 28:14 Prevalence and goals for HYK 29:07 Rumen protected niacin for the transition herd 31:01 Transition BCS recommendations32:05 Take away for boots on the ground dairy producers Featured Article: Associations of Body Condition Score, Body Condition Score Change, and Hyperketonemia with Mastitis, Reproduction, and Milk Production #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #InvisibleCow; #BCS; #ketosis; #pregnancyloss; #Maturecow; #transitiondairy; #HYK; #lipolysis; #dairysciencedigest; #ReaganBluel;

Reproductive physiologists are always trying to improve conception rates for the dairy herd. Double ovsync is one of the best tools in our toolbox to submit cows to first insemination. However, as estrus detection technology becomes more affordable and we learn more about physiology, perhaps combining the expression of estrus at insemination may improve fertility through optimizing ovulation timing. Dr. Julio Giordano and Ana Laplacette worked with their Cornell reproduction team to investigate this theory on over 4600 cows in 2 commercial herds. “We are trying to take advantage of the power of sync of ovulation and the power of estrus” Giordano explains. “To get the best of both, synergize the two.” The only change to the well-known Double ovsync protocol includes a delay in the final administration of GnRh before breeding. The goal, allowing the cows more time to show estrus. Take a moment to listen in to better understand the physiology of this synchronization program and how to improve your herd’s reproductive management. Topics of discussion 2:03 Introduction of Dr. Julio Giordano & Ana Laplacette3:37 Why introduce Estrus detection to double ovsync? 6:25 Treatment description, Double ovsync9:12 Did you cherry pick? 10:04 What metrics do you focus in on to determine the success of synchronization protocol11:36 Considerations to grouping animals to best understand the data 13:57 How did you determine “heat” 15:23 Specific difference between G56 and G80 treatments 16:38 Increase in Estrus observed 2.2% vs 29.9% 17:09 Three types of cows – (1) Show estrus without GnRh, 1/3 (2) Show estrus after GnRh, 1/3 (3) Never show estrus, 1/3 20:01 Anestrus cows – table 5 22:16 Follicle size differences between treatment26:12 Did it work? Take home message for boots on the ground dairy producers 30:41 What is the difference between the estrus and non-estrus cows? 32:16 Follow up project: Give cows 1 week to show estrus after PGH of breeding OvSync Featured Article: Delaying induction of ovulation and timed AI in a Double-Ovsynch protocol increased expression of estrus and altered first service reproductive outcomes of lactating dairy cows #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #DoubleOvSync; #G56; #G80; #cherrypick; #sync; #estrus; #dairy; #Lut; #GnRH; #conceptionrate; #dairysciencedigest; #ReaganBluel;

Despite decades of dedicated research, the rumen still remains a bit of a ‘black box’. This month we feature an article from Dr. Gonzalo Ferreira and his team at Virginia Tech as they try further define how undegradable fiber impacts the rumen's flow rate, and therefore productivity. Comprehending the kinetics of degradation will assist in identifying the ideal combination of ingredients to create a profitable ration for your herd. Could this help you make future planting decisions, as the nation is repairing from several rounds of drought? Does the ‘queen of forages’ belong in your cropping program? Listen in to learn more! Topics of discussion 1:48 Introduction of Dr. Gonzalo Ferreira 3:33 Impact of Fiber in the ration4:15 Compare Alfalfa to temperate grasses 5:16 Segregating Fiber, pdNDF vs uNDF8:04 Design of research rations 9:23 Feeding grasses to lactating dairy cows 12:40 Main variable of interest, ruminal passage rate 13:34 Dry matter intake 16:03 Ration strategy around flow rates and rumen pool size 19:08 Forage sample analysis selection 21:21 Cost of the rations23:32 Plant more Alfalfa or Orchard Grass? 26:36 Take home message for boots on the ground dairy producers Featured Article: Ruminal passage rate and digestibility of fiber from dairy cows consuming diets containing alfalfa and orchardgrass hays with different concentrations of undegradable neutral detergent fiber (uNDF) #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #queenofforages; #Alfalfa; #NDF; #uNDF; #pdNDF; #orchardgrass; #ration; #kinetics; #dairy; #rumen; #dairysciencedigest; #ReaganBluel;

Subacute Ruminal acidosis, commonly referred to as SARA, could be robbing your herd of production. When pH dips too low for too long the biology of the rumen shifts, butterfat slides and overall health of the herd is negatively impacted. But how can you tell if your herd has SARA? This month we invite Dr. Eric Paquet and Felix Huot, from Université Laval in Quebec Canada to explain the method of using DHI milk samples to map the prevalence of SARA in the dairy herd of Quebec. Listen in to learn more - Topics of discussion 1:48 Introduction of Dr. Eric Paquet and Felix Huot 2:55 What is SARA – how is it defined what are the symptoms? 4:42 Pair Feeding – Intake experimental design5:10 Rumen Bolus for research monitoring for calibration6:57 Rumen pH for definition of SARA7:40 7 commercial herds for phase 1 calibration 10:35 Ruminal Biochemistry changed by SARA13:08 Ruminal variability among cows within the same herd14:54 Phase 2: applied statistical model to a dataset of 3000 farms in Quebec to predict prevalence 17:24 Mean, range (min-max) prevalence of SARA18:35 Factors associated with an increase prevalence of SARA19:27 Robotic herds20:50 Seasonal effect 21:40 Higher milk yield 22:05 Take home message for boots on the ground dairy producers Featured Article: Featured Article: Predicting subacute ruminal acidosis from milk mid-infrared estimated fatty acids and machine learning on Canadian commercial dairy herds Background Information:Relationship between farm management strategies, reticuloruminal pH variations, and risks of subacute ruminal acidosis #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #SARA; #machinelearning; #VFA; #milk; #fattyacid; #acidosis; #FA; #dairysciencedigest; #ReaganBluel;