Milk Production and Mammary Extraction of Nutrients by Late Lactating Cross-bred Saanen Goats Supplemented with Betaine in Diet

Abstract

The objective of this study was to investigate the effect of supplementary betaine in diet on milk secretion, milk composition, mammary extraction of nutrients and relevant parameters in late lactating cross-bred Saanen goats. Ten, multiparous, non-pregnant cross-bred Saanen goats of approximately 10 weeks postpartum were used for the study. The animals were divided into two groups of five animals each. Animals in the experimental group received diet containing 4 g betaine per kg of concentrate diet for four weeks, while the control group received similar concentrate diet without betaine as concurrent control. Results showed that milk yields of betaine supplemented animals increased in both treatment and post-treatment periods by approximately 18% of the pretreatment level. Mean values of 4% fat corrected milk (FCM) were significantly higher (p < 0.05) in the betaine supplemented animals (1.23 kg/d) than the control animals (0.98 kg/d). Roughage DMI of the animals receiving betaine supplementation decreased significantly (p < 0.05) during treatment and post-treatment periods. Concentrations of milk fat during betaine supplementation were significantly higher (p < 0.05) than during pre-treatment and post-treatment periods. A significant increase in arterial plasma concentration of acetate (p < 0.05), arterio-venous concentration difference and mammary extraction ratio of acetate tended to increase (0.05 < p < 0.10), while β-hydroxybutyrate, triglyceride and glucose were not affected by dietary betaine supplementation. Betaine supplementation had no effects on plasma volume, blood volume, extracellular fluid volume, intracellular fluid volume and volume of total body water as compared with those of the control animals. Plasma concentrations of IGF-I and thyroxin were not affected by supplementary betaine in diet. These results suggest that dietary betaine supplementation increases milk yield in late lactating cross-bred Saanen goats which is due to an elevation of the plasma acetate level in supplying more source of acetate utilization by peripheral tissues, causing the mammary gland to meet more proportion of other nutrients demand for milk synthesis.