Augmenting milk production in dairy animals – A review

Energy is one of the most important factors limiting the milk production of elite dairy animals. Besides, use of bovine somatotropin (bST) increasing milking frequency, manipulation of photoperiod, innovative shelter are the technologies that increase milk production per cow. Energy intake can be increased by feeding hormonal and non hormonal preparations. Some of the non hormonal methods used to enhance milk production are use of ionophores, certain enzymatic preparations, microbial supplements, use of by pass proteins and fat in diets. Administration of 320 to 960 mg bST at 28 d intervals in a sustained release vehicle increased milk production by 1.5 to 3.4 kg/d through circulating IGF-I level in the serum which in turn affects mammary gland function. Stimulating effect of long photoperiods on circulating concentrations of IGF-I is supported by several observations. Oxytocin to some extent increase milk production by enhancing milk ejection. The primary cause of increased milk production are reduction of intramammary pressure from more frequent milk removal, reduction in the inhibitory effects that certain milk components exert within milk cells and increased hormonal concentration related to milk production (e.g. lactogenic hormones). Recently ionophores as feed additives have been used extensively in ruminant diets to improve efficiency of milk production. Dairy cows and in particular, primiparous cows, needs additional nutrients for growth, may benefit directly or indirectly from the actions of ionophores. Two actions i.e. increased propionic acid production and reduced deamination of amino acids in the gut, result in increased supply of key metabolites for milk production. Dietary yeast appears to be most beneficial during the early or high yielding phases of lactation when dairy cows are under stress to meet nutrient requirements. Identification and selection of low protein degradability containing natural feed ingredients such as maize gluten meal, maize grain, cotton seed cake, fish meal as well as leaf meal of Leucaena and Glircidia for inclusion in lactating diets would be of great economical value.