Betaine is a methyl donor which reduces the susceptibility of rumen microorganisms to stress. The mechanism has been proposed to be by reducing energy expenditure, and thus the heat increment while maintaining the osmotic balance in cows under heat stress.
Supplementing diets with rumen-protected amino acids, has reportedly improved milk yield and components concentration. Lactation performance and reduced inflammatory responses were observed with rumen protected methionine.
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.
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.