When it comes to seeing cows through the transition period, reproduction is the first thing to leave the party, and the last to return, according to Dr. Jose Santos, Professor of Dairy Cattle Nutrition and Reproduction at the at the University of Florida.
Any hiccup in fresh-cow health is likely to put reproduction in jeopardy. “There is a lot of evolutionary biology in play here,” said Santos. “A cow’s priority is not to become pregnant, but to survive, especially when faced with uncertainty. And disease brings uncertainty.”
Santos shared his thoughts on the relationship between transition cow health and reproductive success on a recent episode of The Dairy Podcast Show. He said over the past approximately 15 years, dairy reproduction in the U.S. has improved tremendously, from a historic average 21-day pregnancy rate of about 13-14%, to around 20% or greater today.
And like any good party, successful transition and reproduction depends on the presence of great people. The work culture and human elements on a farm make all the difference, according to Santos, in terms of everything from insemination technique to cow comfort, and udder health to feed delivery.
“When you see the herds that have very high reproductive performance – like pregnancy rates of 50% -- they are doing a lot of good things with cows in the transition period, and they probably have a lot lower disease pressure,” Santos noted.
As an example, he said cows that have a case of mastitis or metritis – compared to those who sail through the transition period without any clinical disease – have an average loss in terms of pregnancy to first AI in the magnitude of 15 percentage points. So, instead of a 40% pregnancy rate, theirs would be closer to 25%. That figure is the result of both lower pregnancy per AI, plus an increase in the losses of pregnancies that do occur.
An interesting general observation from the analysis of data by Santos and his colleagues tracking the performance data of more than 10,000 cows is that the incidence of any disease – not just uterine health issues – is likely to impair reproductive performance. “Diseases that have an inflammatory nature -- which most of them do -- they’re just bad. They only cause damage,” he declared.
“Once you have disease, the ability of that cow to cycle sooner is delayed and reduced,” Santos continued. “So now we have a cow who is anovular for a longer period of time. It becomes a blemish on her record. She won’t show estrus, and if you breed, pregnancy achievement will be less, and the pregnancy loss will be greater.”
Santos’ advice for successfully ushering cows through transition, and thus efficiently achieving subsequent pregnancies, included:
Don’t bother the fresh cows too much. Excessive “fussing” with fresh cows has been shown to interfere with dry-matter intake, which can set off a cascade of other health and metabolic problems.
- Focus on optimal cow comfort.
- Eliminate pathogens like contagious mastitis organisms that should be highly controllable.
- Invest in employee training and education so they understand why it is important to do things a certain way. That understanding is powerful in instilling a sense of ownership and personal pride in daily work.
- Assemble a team of trusted consultants to guide the dairy’s nutrition program, veterinary care, employee training and more. Those individuals should provide science-based solutions to overall herd management and animal well-being.
“When you create issues for cows, they respond with more disease. And disease is always bad for reproduction,” Santos stated.
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