Swiss Brown cow, portrait

Betaine allows dairy cows to better cope with heat stress

Alvaro Garcia

Alleviating heat stress is critical to sustain milk production under warm weather conditions. Maintaining optimum nutrient balance and providing highly palatable, digestible feeds and ample supplies of fresh, clean water, along with shade and ventilation, will go far towards keeping cows comfortable and milk production up.

Heat stress from high environmental temperatures can be compounded by mistakes in managing and feeding cows. Water is the first concern during periods of high temperatures. Water physical properties (heat conductivity and latent heat of vaporization) help transfer heat from the body to the environment. Dry matter intake of lactating cattle is affected when ambient temperatures are outside of the cow’s “comfort zone” (5 to 25 ºC). When ambient temperatures increase beyond 25 ºC, the cow typically reduces intake and as temperatures continue to rise it can finally go off-feed.

Less ingestion of dry matter in hot weather

Dry matter intake can decrease by around 150 g of feed for each degree above 25 ºC. This is just a physiological mechanism by which the cow attempts to reduce the heat increment that results from feed fermentation and metabolism. Heat is produced as a result of microbial fermentation in the pre-stomachs. Low quality, stemmy forages generate more heat of fermentation, contributing to the animal’s total heat load.

This content is locked

Login To Unlock The Content!
The Sun in the sky, sunset

Rumen-protected methionine helps in heat stressed cows

Alvaro Garcia

Warm weather in the US varies in length and intensity depending on the state and can lead to heat stress in dairy cows. It has been estimated that dairy production alone accounts for 37.5% (ca. $900 million) of the annual livestock production losses associated with heat stress. These losses are multi-factorial and mostly attributed to milk production, changes in milk composition, less than optimal reproductive performance, and culling rates.

There’s plenty of research on practices to cool-off cows by evaporative heat losses such as shade, fans, sprinklers, and tunnel cooling. Cows cope with excessive environmental heat conditions by several physiologic strategies such as evaporative heat loss (perspiration), increasing respiration rate (panting), reducing heat of fermentation (caloric increment) by cutting-off intake, and feed sorting to choose more easily digestible feed particles. There has been consensus in the past however, that a decrease in intake to reduce the caloric increment is the primary driver leading to decreased milk yield in cows subjected to heat stress.

This content is locked

Login To Unlock The Content!
Farmhouse milk jugs

Increasing milk fat production by feeding methionine hydroxy analogues

Fernando Diaz

Methionine is one of the most limiting amino acids in lactating dairy cow diets. Methionine hydroxy analogues as 2-hydroxy-4-(methylthio)butanoate are synthetic amino acids in which the amino group has been replaced with a hydroxyl group in order to protect methionine from ruminal degradation. They are normally fed to improve milk and milk protein production of dairy cows. In addition, a recent meta-analysis concluded that supplementation of methionine hydroxy analogues can increase milk fat yield.

In the current dairy market, this parameter is economically important to dairy producers. Many dairy farms experience milk fat depression, which is a syndrome characterized by a reduction in milk fat content. The biohydrogenation theory suggests that this problem is the result of a direct inhibition of fat synthesis in the mammary gland by fatty acid intermediates produced during rumen biohydrogenation of polyunsaturated fatty acids when cows receive diets with high concentration of unsaturated fatty acid and low level of effective fiber.

This content is locked

Login To Unlock The Content!
Cheeses on a wooden shelf

Histidine supplementation increases milk protein production

Fernando Diaz

Methionine and lysine are the main limiting amino acids in lactating dairy cow diets. However, recent research shows histidine may be a limiting amino acid as well. A series of three studies (2015, 2016, 2017) conducted at The Pennsylvania State University’s Dairy Teaching and Research Center reported greater intake and milk protein yield in high-production cows fed low-protein diets supplemented with rumen-protected (RP) histidine.

This content is locked

Login To Unlock The Content!