Feeding of high-yielding bovines during transition phase.

Abstract

Abstract Appropriate feeding during the pregnancy and post-pregnancy period determines both the milk production in the ensuing lactation as well as the reproductive efficiency of the animal. During this period, 3 weeks before and 3 weeks after parturition are very important because dramatic physiological and metabolic adaptations take place during this phase - called as the transition phase. Nutritional imbalances, caused by the low quality of desired nutritious rations, reduced appetite and low ingestion are responsible for depressed performance specifically during the transition period. The lack of knowledge and skill of farmers in feeding-management during this phase exacerbate the situation. The metabolic changes, metabolic adaptations and the nutritional-management strategies to ease out this phase are discussed in this review paper. With the advancement of gestation, the dry matter intake (DMI) of dairy cows declines and is at its lowest (1.7-2.0% of body weight) at parturition. The body condition score (BCS) parallels the DMI, but the aim should be not to lose more than one BCS (in the scale of 1-5) after calving. Simultaneously, with the growth of foetus the nutrient requirements increase and are at their peak before parturition as well as immediately after parturition. The milk production reaches its peak in about 5-8 weeks postpartum, while the diet consumption peaks at 10-14 weeks postpartum. Thus, dairy cows will typically suffer a 6-8-week period of negative energy balance during the postpartum period. The mammary energy requirements at 4-day postpartum are more than three times than that of uterus, with simultaneous increase in requirement of metabolizable protein, especially of methionine and lysine. The high incidence of metabolic and infectious diseases is responsible for the high incidence of inflammatory conditions, mostly immediately after calving. To prevent these diseases pro-inflammatory cytokine release should be avoided in postpartum. The mobilization of body reserves especially fat and protein; and hepatic gluconeogenesis takes place immediately after parturition leading to increased levels of β-hydroxy butyric acid and non-esterified fatty acids, which act as a gateway for a number of metabolic diseases. The transition phase can be eased by increasing DMI, feed conversion efficiency, density of ration, and protein supplements rich in rumen undegradable protein; by using anionic mineral mixture, optimizing roughage to concentrate (R:C) ratio, optimum physically effective fibre length of forages/silage/hay, dietary buffers, feed additives such as inflammation modulators, protected nutrients, glucogenic precursors and direct fed microbials/probiotics; and by following phased feeding programme.