Puberty and the induction of puberty in female boer goat kids

Author: P.C. Greyling and C.H. van Niekerk
Year: 1990
Issue: 4
Volume: 20
Page: 193 - 200

Female Boer goat kids were randomly allocated (post weaning) to 2 X 3 factorial design experiments for two observation periods, to monitor puberty and the induction thereof. Treatments for each period (December and April weaning seasons respectively) included three male stimulation treatment groups, viz. a permanent ram group (permanent presence of a male), a teaser ram group (limited daily exposure to a male) and a control group  (isolated from males). All does were maintained on either a high- or low-energy diet. No significant differences in age and mass at puberty were found between the two energy diets, nor between ram treatment groups. Mean masses and age at puberty were 31,1 and 27,4 kg and 157,2 and 191,1 days for kids weaned in April and December, respectively. Kids weaned in April (breeding season) exhibited oestrus significantly (P < 0,05) earlier than those weaned in December. The continuous presence of a male had a significantly (P < 0,05) beneficial effect on oestrous response. By using linear regression analysis, no significant correlation could be found between mass and age at first oestrus. It is evident from the serum LH values that the pituitary in the Boer goat is active from 13 weeks of age, irrespective of season, ram-effect or level of nutrition. Elevated serum LH values were recorded before the occurrence of first oestrus. Kids weaned in the breeding season were found to have a significantly (P < 0,05) higher mean LH level, which may reflect higher pituitary activity during this period. Progesterone profiles of individuals indicated a relative high incidence of silent heats. Deduced from serum progesterone concentrations, cyclic activity for kids weaned in December and April on a high- or low-energy diet, started at 7,6 ±3,4; 9,1 ± 4,3; 7,6 ± 3,5 and 12,7 ± 6,8 weeks, respectively, following weaning. Contact with male goats had an effect upon synchronization and timing of puberty, entrained by photoperiodic stimulation, while nutrition as such played a minor role. The effect of the interaction between these factors on puberty is difficult to assess.




Keywords: Boer goat, female kids, high-/low-energy diet, puberty, ram-effect, season
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