Peripheral Patterns of Growth Hormone, Luteinizing Hormone, and Progesterone Before, at, and after Puberty in Buffalo Heifer

Abstract

Buffalo, the premier dairy animal in India, suffers from slow growth rate, delayed puberty, and silent heat. It is not known whether the delay in puberty in such animals is due to the delay in expression of hypothalamus-pituitary-gonadal functions. To determine the changes in growth hormone (GH), luteinizing hormone (LH), and progesterone before, at, and after puberty of Murrah buffalo heifers, six Murrah buffalo heifers (21.92 61.09 months of age, 269.67 6 7.97 kg body weight) were assigned to well-ventilated individual pens and fed a roughage-concentrate diet to provide weight gain of 0.4 kg/day. Blood samples were collected at 3-day intervals during a period of 12 months, and plasma harvested from blood samples was assayed for progesterone, LH, and GH. The day that plasma progesterone was greater than 1 ng/mL for three consecutive sampling days was defined as the day of puberty. Heifers attained puberty at an average age of 31.53 6 0.88 months with a body weight of 380.67 66.42 kg. Progesterone levels were very low (0.20 to 0.30 ng/mL) during the pre-pubertal period. There were two distinct elevations before the day of puberty onset. Plasma LH and GH concentrations increased (P < 0.05) during the months preceding puberty and were highest during the month before puberty. GH and LH were positively correlated (P < 0.05) prior to (r = +0.59) as well as after puberty (r = +0.42). A positive correlation (P < 0.05) between LH and body weight during the pre-pubertal period (r = +0.61) and thereafter, negative correlation (P < 0.05) during post-pubertal period (r = 20.64) was noted. GH and body weight showed positive correlation both before puberty (r = +0.92, P < 0.01) and after puberty (r = +0.32, P < 0.05). Results suggest that both GH and LH are equally important and vital cues in inducing onset of ovarian functions in buffalo heifers.

Keywords:

• Buffalo
• Puberty
• Progesterone
• Luteinizing hormone
• Growth hormone

ACKNOWLEDGMENTS

The authors thank Dr. Mark Hennies, Institut fuer Physiologie, Biochemie und Hygiene der Tiere, Rheinische Friedrich-Wilhelms-Universitaet, Bonn, Germany, for the generous gift of highly specific bGH antibody. The supply of highly purified reference preparation of bovine GH, bovine LH, and bovine LH antiserum by Dr. A. F. Parlow, NHPP, Harbor-UCLA Medical Centre, CA 90509, United States Department of Agriculture, USA is gratefully acknowledged. Financial assistance provided by National Agricultural Technology Project PSR No. 47, Indian Council of Agricultural Research, New Delhi, India for this study is also duly acknowledged.

Notes

NDRI Annual Report. National Dairy Research Institute, Karnal, Haryana, India, 1995–1996