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Reprod Nutr Dev

Title:		Effects of bull exposure and body growth on onset of puberty in Bunaji and Friesian x Bunaji heifers
Author(s):		Rekwot P; Ogwu D; Oyedipe E; Sekoni V;
Address:		"Artificial Insemination Unit, National Animal Production Research Institute, Ahmadu Bello University, Zaria, Nigeria. rekwot@abu.edu.ng"
Journal Title:		Reprod Nutr Dev
Year:		2000
Volume:		40
Issue:		4
Page Number:		359 - 367
DOI:		10.1051/rnd:2000104
ISSN/ISBN:		0926-5287 (Print) 0926-5287 (Linking)
Abstract:		"A total of ninety seven pre-pubertal Bunaji (BJ) and Friesian-Bunaji (FR x BJ) heifers were allotted randomly to two treatments groups for a period of 15 months. The treatment groups consisted of the followings: Mature Bull Exposure (MBE) and No Bull Exposure (NBE). Heifers were body condition scored and their live weights recorded on 28 days consecutive intervals. A heifer tactile stimulation in bull bio-stimulation. was considered to have attained puberty if she displayed oestrus, had a palpable corpus luteum with an associated P4 concentration > 1 ng x mL(-1). The onset of puberty was significantly earlier in MBE heifers (23.1 +/- 0.4 months) than NBE heifers (26.4 +/- 0.4 months). The mean ages at puberty for MBE-BJ, NBE-BJ, MBE-FR x BJ, NBE-FR x BJ were 24.3, 27.8, 22.1 and 25.0 months respectively. More MBE heifers (70.8%) attained puberty between 17 and 24 months of age than NBE heifers (18.3%) and on the same ages, more FR x BJ heifers (62.0%) than BJ heifers (25.5%). The mean live weight of MBE heifers at puberty (224.4 +/- 4.2 kg) was significantly lower than that of the NBE heifers (255.8 +/- 4.2 kg). The FR x BJ heifers attained puberty at a significantly higher live weight (270.2 +/- 4.2 kg) than the BJ heifers (228.6 +/- 4.2 kg). The use of a vasectomised bull especially in some elite farms that rely on artificial insemination services may be an effective management tool that can decrease age at puberty. More work is required to determine the relative contribution of visual, auditory, olfactory, pheromonal and tactile stimulation in bull biostimulation"
Keywords:		"Age Factors Animals Cattle/*growth & development/physiology Corpus Luteum/physiology Estrus Detection Female Male Progesterone/blood Radioimmunoassay/veterinary Sexual Behavior, Animal *Sexual Maturation Weight Gain;"
Notes:		"MedlineRekwot, P Ogwu, D Oyedipe, E Sekoni, V eng Clinical Trial Randomized Controlled Trial Research Support, Non-U.S. Gov't France 2000/11/18 Reprod Nutr Dev. 2000 Jul-Aug; 40(4):359-67. doi: 10.1051/rnd:2000104"