Mitigation of Heat Stress in Dairy Cattle by Dietary Supplementation of Octanoic Acid

View the project final report

Commodities

• Animals: bovine
• Animal Products: dairy

Practices

• Animal Production: animal protection and health, feed additives, feed rations

Heat stress is responsible for $897 million of loss to the United States dairy industry, primarily through depressed feed intake and resulting losses in milk production. Heat stress for dairy cattle is common even in the Northeast; for instance, data from Penn State’s local weather station demonstrates that ambient temperature can reach as high as 38°C with almost 100% relative humidity during summer; these conditions are deemed as severe heat stress for dairy cows. Farmers and researchers have discovered and utilized many methods to minimize the negative impact of heat stress, including fans, sprinklers, and shades. For many farms, these methods are either cost prohibitive or do not fit within their management system. Ghrelin is a hormone that exists in active (acylated) and inactive (non-acylated) forms and that is involved with modulation of feed intake, thermogenesis, energy expenditure, adipogenesis, and locomotive activity. Octanoic acid (OA) is an important substrate of the ghrelin acylation process and dietary OA supplementation has been shown to stimulate appetite and decrease body core temperature in rats and humans. However, few studies about dietary OA supplementation had been conducted on dairy cows. Therefore, we propose to evaluate the effects of dietary OA on lactating dairy cows under moderate heat stress conditions. The objectives are to: investigate the impact of dietary OA on plasma active ghrelin concentration, core body temperature, dry matter intake, and milk production under moderate heat stress conditions.

The objectives of this project are:

1. Investigate the impact of dietary octanoic acid on plasma acylated ghrelin concentration in dairy cows under moderate heat stress;

2. Investigate the impact of dietary octanoic acid on core body temperature in dairy cows under moderate heat stress;

3. Investigate the impact of dietary octanoic acid on dry matter intake and energy intake in dairy cows under moderate heat stress;

4. Investigate the impact of dietary octanoic acid on milk and component production under moderate heat stress.