Preovulatory follicular status and diet affect the insulin and glucose content of follicles in high-yielding dairy cows

• Published in: Animal reproduction science 2000-12, Vol.64 (3), p.181-197
• Main Authors: Landau, S, Braw-Tal, R, Kaim, M, Bor, A, Bruckental, I
• Format: Article
• Language: English
• Subjects: Animal Feed; Animals; Blood Glucose - metabolism; Cattle; Dairying; Estrous Cycle - blood; Estrus Synchronization; Feeding and nutrition; Female; Glucose - metabolism; Insulin - blood; Insulin - metabolism; Lactation; Milk - metabolism; Nutritional Physiological Phenomena; Ovarian Follicle - diagnostic imaging; Ovarian Follicle - physiology; Ovary; Ovary - diagnostic imaging; Ovary - physiology; Progesterone - metabolism; Ultrasonography
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/S0378-4320(00)00212-8

Insulin and glucose may be limiting factors for ovarian function in dairy cows genetically selected for high milk yield. The effects of nutrition on the intrafollicular content of insulin and glucose were investigated in Israeli Holstein dairy cattle fed a basic total mixed ration and producing 34–39 kg of milk daily. In experiment 1, carried out in 11 oestrus-synchronised cows, little variation in insulin concentration was found in plasma sampled during the luteal phase, but high variation was found in plasma sampled during the follicular phase. Therefore, in order to prevent confounding the effects of diet and of phase in cycle in the following experiments, experimental diets were fed during the luteal phase of synchronised oestrus cycles. In experiment 2, designed as Latin-Square, six cows received sequentially diets containing 17.1 (control) or 19.7% of crude protein, using two sources of supplementary protein, i.e. soyabean meal (SBM) and corn gluten meal (CGM), differing in ruminal degradability and leucine content. When dry matter intake was used as covariant, plasma insulin on day 16 was 29.5 and 26.4% higher in cows fed diets containing SBM and CGM than in the control ( P