An evaluation of the effect of altering nutrition and nutritional strategies in early lactation on reproductive performance and estrous behavior of high-yielding Holstein-Friesian dairy cows

• Published in: Journal of dairy science 2011-07, Vol.94 (7), p.3510-3526
• Main Authors: Gilmore, H.S., Young, F.J., Patterson, D.C., Wylie, A.R.G., Law, R.A., Kilpatrick, D.J., Elliott, C.T., Mayne, C.S.
• Format: Article
• Language: English
• Subjects: Animal Nutritional Physiological Phenomena; Animal productions; Animals; Biological and medical sciences; body condition; body weight; breeding; calving; Cattle - physiology; conception rate; cow feeding; crude protein; dairy cows; Dairying - methods; Diet - veterinary; Dietary Fats - administration & dosage; Dietary Proteins - administration & dosage; Dietary Supplements; early lactation; embryogenesis; energy balance; Energy Metabolism; estrus; Estrus - physiology; Feeding. Feeding behavior; Female; fertility; Fundamental and applied biological sciences. Psychology; high-yielding dairy cow; Holstein; industry; insemination; Lactation - physiology; low protein diet; methionine; milk yield; nutrition; periodicity; Postpartum Period; Pregnancy; Pregnancy Rate; Reproduction - physiology; reproductive performance; Sexual Behavior, Animal - physiology; Starch - administration & dosage; Terrestrial animal productions; Time Factors; Vertebrates; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2010-3547

Reproductive performance in the high-yielding dairy cow has severely decreased in the last 40 yr. The aim of this study was to compare the effectiveness of 4 nutritional strategies in improving the reproductive performance of high-yielding dairy cows. It was hypothesized that offering cows a high-starch ration in early lactation would enhance the onset of luteal activity, and that decreasing the severity of negative energy balance in the early postcalving period would improve reproductive parameters. Nutritional regimens aimed at improving fertility were applied to 96 Holstein-Friesian dairy animals. Upon calving, animals were allocated in a balanced manner to one of 4 dietary treatments. Primiparous animals were balanced according to live weight, body condition score and calving date. Multiparous animals were balanced according to parity, previous lactation milk yield, liveweight, body condition score and calving date. Treatment 1 was based on an industry best practice diet (control) to contain 170g of crude protein/kg of dry matter. Treatment 2 was an individual cow feeding strategy, whereby the energy balance (EB) of individual animals was managed so as to achieve a predetermined target daily EB profile (±10MJ/d). Treatment 3 was a high-starch/high-fat combination treatment, whereby an insulinogenic (high-starch) diet was offered in early lactation to encourage cyclicity and followed by a lipogenic (low-starch, high-fat) diet to promote embryo development. Treatment 4 was a low-protein diet, containing 140g of crude protein/kg of dry matter, supplemented with protected methionine at an inclusion level of 40g per animal per day. The nutritional strategies implemented in this study had no statistically significant effects on cow fertility measures, which included the onset of luteal activity, conception rate, in-calf rate, and the incidence of atypical cycles. The individual cow feeding strategy improved EB in early lactation but had no benefit on conception rate to first insemination. However, conception rate to second insemination, 100-d pregnancy rate (from the commencement of breeding), and overall pregnancy rate tended to be higher in this group. The high-starch/high-fat treatment tended to decrease the proportion of delayed ovulations and increase the proportion of animals cycling by d 50 postcalving. Animals that failed to conceive to first insemination had a significantly longer luteal phase in the first cycle postpartum and a longer inter-ovulato