Posted by Richard Shepardson, M.S. and Matthew Sellers, Ph.D on Jun 4, 2020 7:00:00 AM
Minimize the days spent in negative energy balance as AN important strategy to improve peak milk and reproductive performance in cows during early lactation
The onset of lactation is accompanied by extreme physiological shifts for dairy cows and causes a gap between the biochemical energy necessary to support lactation and the dietary energy taken in through dry matter intake (DMI). If cows are not obtaining adequate nutrients through feed, they enter negative energy balance (NEBAL) and must utilize body reserves (i.e. adipose tissue) to make up the difference. Cows in NEBAL, and those that remain in NEBAL for extended periods of time, will decrease in body weight and condition which can lead to a variety of metabolic and reproductive issues. Minimizing the time spent in NEBAL improves peak milk and reproductive performance.
IMPROVING ENERGY BALANCE AND REPRODUCTIVE SUCCESS
Minimizing days spent in NEBAL is an important strategy to improve reproductive success. Effects of energy balance on reproductive performance have been well documented. Butler (2000) and Gumen et al. (2011) will be briefly reviewed for the purposes of this paper.
Energy balance can impact the ability of the cow to return to estrous and ability to carry a calf. Decreased reproductive success is also associated with increased plasma non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHBA) concentrations present during NEBAL as the body mobilizes energy reserves. Negative energy balance alters luteinizing hormone (LH) pulse frequency and decreases ovarian sensitivity to LH. Circulating blood progesterone, often referred to as the “pregnancy hormone,” is decreased when cows are in NEBAL, meaning that these cows also have decreased fertility. Oocyte quality and function of the corpus luteum are also negatively impacted by prolonged NEBAL. Carvalho et al., (2014) demonstrated that pregnancies per artificial insemination (P/AI) at 40 days in milk for cows that lost, maintained, or gained body condition in the first 21 days of lactation was 25%, 38%, and 84%, respectively. These numbers were mirrored by the P/AI at 70 days as well.
Interestingly, energy corrected milk yield of all three groups was not different, nor was body condition score at calving. Finally, Domecq et al. (1997) showed that cows that lost 0.40 units of body condition decreased first service conception rate by 17%, and cows that lost 0.80 units of body condition decreased by 20%.
In order to improve reproductive success and peak milk yield, dairy managers and nutritionists must focus on returning their cows to positive energy balance (PEBAL) as quickly and efficiently as possible.
Download the full white paper to explore these strategies on minimizing the time spent in NEBAL for improved reproductive performance:
- IMPROVING ENERGY BALANCE AND REPRODUCTIVE SUCCESS
- FATTY ACID BALANCING AND ENERGY OUTCOMES
- ECONOMICS OF IMPROVED BODY CONDITION AND REPRODUCTION IN FRESH COWS
Topics: ANIMAL NUTRITION