Florida researchers began a generational study in 2007 that is still years in the making. It all began with the investigation of the impact of heat stress on dry cows to measure changes that might occur to the calf incubating inside the hot dam, like a crock pot.

In addition to seeing negative production impacts on mama, the researchers began to measure numerous changes in the damaged calf coming out of the heat stressed dry cow. This month’s edition, we’ll be interviewing Dr. Jimena Laporta, of the University of Wisconsin, to better understand the physiological changes of the calf that results in lost production for her entire life. She and her team measured changes in mammary and adrenal gland development.

Several separate papers have been peer reviewed over the 17 years of research. Many are linked at the bottom of the show notes for additional reference.

Listen in to understand how heat stressed dry cows can destroy your favorite cow families’ production records.

This month features two released paper titled: (1) Carry-over effects of maternal late-gestation heat stress on granddaughter’s growth and mammary gland development (ck out histology – Fig 1&2) (2) Programming effects of intrauterine hyperthermia on adrenal gland development

Topics of discussion

1:58 Introduction of Dr. Jimena Laporta 4:17 Describe the experimental design 6:19 Description of the generations impacted through in utero heat stress 7:29 The biological link between the grand dam and the grand daughter (F2) 9:16 Eight years of research to collect multigenerational data 10:39 F1 management in WI beginning at 8 weeks 12:00 F1 mammary implications following heat stress while developing in utero 13:32 F2 calves – changes as a result of dam’s exposure to heat stress while developing in utero 15:01 Early mammary growth 15:32 What is causing these differences in F2 17:35 Lumen space and estrogen receptors 19:06 Summary of 3 generations of damage 20:34 Should I build a lactating barn or dry cow barn? 22:39 The Adrenal Gland 27:38 Adrenal effect on inflammation 28:56 What do you want Boots on the ground dairyman to know

Background Information: Temperature Humidity Index (THI) 2020 Dairy Science Digest Podcast interview 2020: Late-gestation heat stress impairs daughter and granddaughter lifetime performance (economic impact) 2016: In utero heat stress decreases calf survival and performance through the first lactation

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #heatstress; #fetalprogramming; #F1; #milk; #adrenal; #mammarydevelopment; #mammary; #dairysciencedigest; #ReaganBluel;

Choline, a pseudovitamin, is required by all mammals including the dairy cow for many essential functions. Research in supplementing rumen protected choline really took off about twenty years ago, however continues today to best understand how this feed through additive can positively influence profitability. Dr. Usman Arshad joins the conversation for this episode to highlight his comprehensive summary of all the peer reviewed, published research completed on Choline. Listen in to best understand the assumed mode of action choline uses to help provide an improved efficiency in milk production for the majority of the lactation, even when only fed during the 42-day transition period.

The findings we discuss are published in the recently released paper titled: Exploring choline's important roles as a nutrient for transition dairy cows

Topics of discussion

1:19 Introduction of Dr. Usman Arshad 2:17 What is Choline? 3:45 Phospholipid production – choline’s role 6:15 How does choline impacts the transition Cow 7:46 Fatty acid impact on the Liver 8:39 Major factor choline plays on fatty acid transport 13:16 Twenty year average Milk Response when feeding choline for 42 days (-21 to 21 dim) 15:47 Milk Response when feeding choline – more current average from 2020-2024 17:18 Mode of action, intestinal lining? 20:02 Additional possible modes of action 21:47 Choline as a treatment for fatty liver 23:24 Choline results in elevated milk yield, regardless of body condition score 26:16 Inflammation through in early lactation 27:29 Energy cost of bacterial infection 30:30 What’s the one take home message for boots on the ground dairymen 31:35 Return on investment calculations

Featured article: Exploring choline's important roles as a nutrient for transition dairy cows

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #Choline; #transition; #transitiondairy; #vitamin; #fattyacid; #negativeenergybalance; #TMR; #dairysciencedigest; #ReaganBluel;

DSD 5.3 | Slight modifications of CIDR Sync - help or hinder?

In this time of heifer inventory shortage – getting heifers pregnant (in a timely fashion) is even more important than ever.

Contract heifer growers in California sought the help of Dr. Fabio Lima and his team at UC Davis to best understand the use of a 6-day CIDR sync with variable rates of GnRH could increase pregnancies when bred to sexed semen.

The findings we discuss are published in the recently released Journal of Dairy Science article titled: Effect of 200 μg of gonadorelin hydrochloride at the first GnRH of a CIDR Synch program on ovulation rate and pregnancies per AI in Holstein heifers.

Listen in to hear the results and nuanced details of controlling reproductive structures using timed AI protocols.

Topics of discussion

1:03 Production costs of heifer rearing - survey results 2:09 Introduction of Dr. Fabio Lima 3:46 Description of the project 4:20 TAI protocol description 5:31 Varying GnRH dose 6:34 What is the function of GnRH in the heifer? 7:51 Hallmark of a successful synchronization 8:24 Results of ultrasound (ovulation) and P4 blood sample analysis 10:04 Did increased ovulation translate into improved pregnancy outcome? 10:44 Pregnancy at d47, 100% sex semen discussion 13:41 Relationship of Luteinizing hormone and progesterone 15:16 What causes elevated circulating progesterone 16:30 How did we land on 2cc of GnRH to begin with? 18:34 Does increased GnRH cause increased twinning? 21:02 What do you want boots on the ground dairymen to know 23:01 What if you cherry picked? 23:32 Sometimes the plan doesn’t work – but that’s why we do research! Featured article: Effect of 200 μg of gonadorelin hydrochloride at the first GnRH of a CIDR Synch program on ovulation rate and pregnancies per AI in Holstein heifers

Articles also discussed in the podcast: Heifer study using 100 and 200 ug in 5-d CIDR Synch protocol. https://doi.org/10.1016/j.theriogenology.2023.04.026

Studies showing the implication of progesterone for double ovulation (a proxy for twining) and progesterone. https://doi.org/10.3168/jds.2018-14410

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #gnrh; #CIDRsync; #twinning; #pregnancy; #heiferdevelopment; #TAI; #lutenizing; #dairysciencedigest; #ReaganBluel;

Getting the fresh cow off to a strong start has ripple effects for her entire lactation. Subclinical mastitis rarely gets treated due to an unawareness or a lack of interest in pulling her from the tank. Nisin is a naturally occurring antimicrobial that’s been used widely as a food preservative. Dr. Zelmar Rodriguez and his team from Michigan State University looked at using this familiar antimicrobial to treat subclinical mastitis. The result, reduced clinical cases of mastitis.

Listen in to learn more about the return on investment of using Nisin on subclinical mastitis found in the first week of milk using CMT.

These findings are published in the recently released paper titled: Economic impact of treatment of subclinical mastitis in early lactation using intramammary nisin

Topics of discussion

1:20 Introduction of Dr. Zelmar Rodriguez 2:20 What is nisin 3:42 No dump milk 4:10 Subclinical mastitis assessment 5:00 CMT discussion 6:00 What day should we sample 7:00 Subclinical mastitis prevention 7:39 How does CMT work? 8:46 Factors that impact effectiveness 9:18 What will nisin not work on – gram negative discussion 12:36 ROI/cow 13:23 Treatment regimen 13:42 Assessment to begin protocol 15:36 Effect of employee training 17:16 Model at herd level – ROI 19:33 FDA status 20:22 Limitations of using DHIA hot sheet 22:13 What do you want boots on the ground dairymen to know Featured article: Economic impact of treatment of subclinical mastitis in early lactation using intramammary nisin

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #nisin; #earlylactation; #subclinical; #mastitis; #treatment; #dairysciencedigest; #ReaganBluel;

Efficient production is the name of the game, and the key to an efficient cow is her rumen microbiome. The highlighted research this month focuses in on the intersection of Genome of the host cow, Microbiome within the rumen and the Intersection of the two.

To best understand the rumen efficiency story we talk this month with Dr. Guillermo Martinez Boggio from University of Wisconsin, about his recently released paper titled: Host and rumen microbiome contributions to feed efficiency traits in Holstein cows. Here they studied how the rumen and the host interact and if that interaction can become a selection trait in the future.

Much of the discussion today is focused around Carbon chasing. Just like “a penny saved is a penny earned,” whenever carbon is conserved by the rumen microorganism, energy is conserved. This carbon unit of energy can then be used to produce more milk when conserved. Listen in to learn more about the interconnected web between the cow and her microbiome.

Topics of discussion

1:52 Introduction of Dr. Guillermo Martinez Boggio 3:15 Description of project 3:41 Dry matter intake vs Residual feed intake 5:09 Efficient use of Carbon 7:04 Saved energy yields more 8:25 Community of rumen organisms 10:29 What model best served to identify the most efficient digestion 11:35 Using microbiome as another source of information used genomic equation 12:02 Genome | Microbiome | Interaction of MicrobiomeXGenome 12:17 The cow controls the rumen microbiome 12:51 Sire selection traits 14:08 How to obtain the most reliable breeding values 15:35 Using the rumen microorganisms for prediction and selection 16:45 Future research What do you want dairy producers to know from your research 17:21 Identify the “extreme” cows 18:12 Proxy traits

Featured article: Host and rumen microbiome contributions to feed efficiency traits in Holstein cows.

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #microbiome; #methanereduction; #sustainabledairy; #rumen; #stillbirth; #dairysciencedigest; #ReaganBluel;

Beef on dairy is here to stay. These cross animals generate a revenue stream for dairies as it lubricates the parallel industry of beef production. Much research is being poured into this topic to ensure producers can make wise breeding choices going forward. This month we talk with Bailey Basiel from Penn State University, about their recently released paper titled: The impact of beef sire breed on dystocia, still birth, gestation length, health, and lactation performance of cows that carry beef x dairy calves.

While we all know how desirable this cross calf is to the market, there’s very little knowledge about how these breedings impact the dam, until now. Listen in to how this research team sought to determine if there were any negative production implications to your dairy herd when you breed to beef.

Topics of discussion

1:27 Introduction of Bailey Basiel 2:26 Objectives of the trial – Impact carrying beef on dairy calf might have on the dairy cow 3:24 Board invited review of Beef on Dairy 4:05 Historical background of Beef on Dairy 5:15 Calf fed Holstein model 7:54 Data set description 10:05 Beef semen description 10:47 Gestation length 13:00 Management changes based on gestation length 14:00 Wagyu crosses 15:00 Long gestation, does that equal stillbirth? 17:10 Health impacts for dams bred to beef semen 20:35 Next research / records needed for genetic assessment - 23:23 What do you want dairy producers to know from your research Featured article: The impact of beef sire breed on dystocia, still birth, gestation length, health, and lactation performance of cows that carry beef x dairy calves.

Also mentioned in the discussion:

Translational Animal Science Article - Beef on Dairy Review DSD 1.5 | Beef on Dairy – sire conception rate, Taylor McWhorter DSD 4.6 | Accounting for Accelerated genetic improvement, Dr. Asha Miles

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #beefondairy; #sexedsemen; #calffedmodel; #gestation; #stillbirth; #dairysciencedigest; #ReaganBluel;

Over the past 30 years the reproduction status of dairy has improved substantially, largely due to research around reproduction synchronization. This month we talk to Dr. Paul Fricke and Megan Lauber from the University of Wisconsin, about their recently released paper titled: Effect of postpartum body condition score change on the pregnancy outcomes of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after a synchronized estrus versus a synchronized ovulation.

We discuss the how to maximize the equation of fertility, through management. Once optimized, you’ll find your herd entering the “high fertility cycle”. When all the stars align, production is high – disease is low and you are able to begin to stack reproductive technologies – such as genomically determined breedings using sexed and beef semen use following the ideal synchronization.

Listen in to learn how to get your herd there and the physiology behind it.

Topics of discussion

1:54 Introduction of Dr. Paul Fricke & Megan Lauber 4:23 Objectives of the trial – stacking reproductive strategies 3:34 On farm monitoring – data collected 6:10 Getting all the cows on day 7 – the key to unlocking fertility 7:44 The history of Luteolysis – why is it so critical? 9:57 Rate limiting step of pregnancy 12:03 2019-2021 xx and beef semen usage 13:54 Research protocols and design 16:20 Equation of reproduction; comparing double ovsync vs estrus 17:50 Estrus or Double ovsync for Sexed semen 16:14 Day 19 – 40 pregnancy loss 17:30 What’s happening when the GnRH shot is given? 22:13 The impact of Body Condition Score (BCS) change on fertility | >0.5 24:53 High fertility cycle 25:52 Not all cows loose condition through transition, those that did were impacted 26:38 Results: Double ovsync helps mitigate poor transition (Figure 4) 29:09 Why does it work? What physiology controls it? 30:15 Fat regulates GnRH?! 32:30 What do you want dairy producers to know from your research Featured article: Effect of postpartum body condition score c hange on the pregnancy outcomes of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after a synchronized estrus versus a synchronized ovulation. Also mentioned in the discussion: Characterization of semen type prevalence and allocation in Holstein and Jersey females in the United States

#2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #reproductionrevolution; #highfertilitycycle; #Ovsync; #DoubleOvSync; #transition; #transitiondairy; #dairysciencedigest; #ReaganBluel

Pregnancy is the key to profitability, ensuring your herd remains in the most profitable phase of production. However, these early embryos are delicate and often are not carried out through the entire 283 days of gestation. This month we talk with Dr. Stephen LaBlanc, from the University of Guelph about quantifying the frequency of early pregnancy loss in healthy animal and his team’s quest to determine the impact of a failed transition on the cow’s ability to carry the pregnancy to term.

Through management, a producer can prevent the spiral of negative events that result in increased odds of pregnancy loss. The research team determined day 19 pregnancy and tracked the success, or failure, through day 63. Listen in to hear what different parameters they found to have an increased probability of early pregnancy loss.

These findings were published in the Journal of Dairy Science article titled, “The associations of inflammatory and reproductive tract disorders postpartum and early pregnancy loss in dairy cows” This open access article, is available for download to view while you listen in!

Topics of discussion

1:32 Introduction of Dr. LaBlanc 2:15 Description of Research Herds 3:34 On farm monitoring – data collected 5:55 Uterine sampling 7:32 Uterine cytology at 5 weeks postpartum 8:53 Blood progesterone 9:53 Common cycling rate in early lactation 10:52 Day 19 pregnancy analysis 14:03 Figure 1: Predicted probably of pregnancy – Healthy vs diseased transition 15:19 Conception frequency 16:14 Day 19 – 40 pregnancy loss 17:30 Metritis hangover 18:34 Figure 2: Predicted probably of pregnancy – number of clinical disease 20:00 Single disease vs multiple clinical diseases impact on pregnancy loss 22:31 Driving force to what predicts pregnancy loss in a dairy herd 24:13 One in Five cows 24:49 One two punch of failure 25:05 Inflammation effect on the ovary 27:53 What do you want dairy producers to know from your research #2xAg2030; #journalofdairyscience; @jdairyscience; #openaccess; #MODAIRY; #earlyembryonicloss; #pregloss, #Ploss; #transition; #transitiondairy; #dairysciencedigest; #ReaganBluel

https://www.journalofdairyscience.org/article/S0022-0302(23)00726-9/fulltext