HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Burke, C. R. Articles by Roche, J. R. Search for Related Content PubMed PubMed Citation Articles by Burke, C. R. Articles by Roche, J. R.

Effects of Pasture Feeding During the Periparturient Period on Postpartum Anovulation in Grazed Dairy Cows¹

Dexcel Limited, Private Bag 3221, Hamilton, New Zealand

² Corresponding author: chris.burke{at}dexcel.co.nz

Extended postpartum anovulatory intervals (PPAI) are a major contributor to infertility in seasonal dairy systems constrained to 365-d calving intervals. This study was conducted to evaluate the effects of pasture-based dietary energy intakes during the transitional calving period on PPAI. Sixty-eight multiparous Holstein-Friesian cows were assigned to high [11.9 kg of dry matter (DM)/d] or low (4.8 kg of DM/d) pasture intakes for 29 ± 7.7 d prepartum. After calving, cows within each prepartum diet were assigned to either a high (13.5 kg of DM/d) or low (8.6 kg of DM/d) pasture intake for 35 d in a 2 x 2 factorial arrangement. Progesterone concentrations were measured in milk samples collected twice weekly to determine PPAI, which was defined as the day on which progesterone level was elevated to 3 ng/mL with subsequent concentrations being consistent with an ovulatory cycle. Blood samples were collected before initiation of treatments, and at d –21, –14, –7, 0 (day of calving), 1, 2, 3, 4, 7, 14, 21, 28, and 35 in all cows. The PPAI was associated with body condition score, concentrations of plasma insulin and insulin-like growth factor-I, and growth hormone. Postpartum intake did not affect these metabolic hormones or PPAI, but yield of FCM during the first 35 d was reduced by 23% among cows on a restricted intake. No relationships were found between PPAI and milk production characteristics. These data demonstrate that when pasture is the sole dietary source during the calving transition period, PPAI may be influenced by prepartum intake levels, whereas postpartum intake influences milk yield, but not PPAI. The underlying mechanism(s) that associates the prepartum period to PPAI may involve the sensitivity of the growth hormone–insulin-like growth factor axis to dietary intake levels. Nonetheless, PPAI in grazing multiparous dairy cows appears largely unresponsive to intake levels during the calving transition period.

Key Words: postpartum anovulation • metabolic hormones • reproduction • nutrition

This article has been cited by other articles:

				L. M. Chagas, P. J. S. Gore, G. Graham, K. A. Macdonald, and D. Blache Effect of Restricted Feeding and Monopropylene Glycol Postpartum on Metabolic Hormones and Postpartum Anestrus in Grazing Dairy Heifers J Dairy Sci, May 1, 2008; 91(5): 1822 - 1833. [Abstract] [Full Text] [PDF]