Body condition score is a critical factor determining the onset of puberty in Blanca Andaluza female goat kids

This study examines the effect of body condition score (BCS), independently of bodyweight (BW), on the onset of puberty in Blanca Andaluza female kids born in Autumn (November). Thirty-six female kids were distributed into three groups according to their BW and BCS: low BW and low BCS (LL, n = 10), low BW and high BCS (LH, n = 10), and high BW and high BCS (HH, n = 16). Feeding was adjusted weekly so that the animals would gain ~50 g per day. Oestrus was checked daily using young vasectomised bucks fitted with a marking harness. The ovulation rate was determined by transrectal ultrasonography 10 days after the identification of oestrus. Plasma samples were obtained weekly for progesterone determination. Changes in BW and BCS were also recorded weekly. The BCS had a clear effect on the date of first ovarian activity and first detected oestrus. The HH kids experienced the earliest onset of puberty (31 August ± 2.4 days) although no significant difference was seen compared with the LH group (19 September ± 8.7 days). A significant difference was recorded, however, in comparison with the LL group (25 October ± 7.8 days) (P < 0.001). No effect of BCS was observed on ovulation rate. These results show that, in Blanca Andaluza female kids, the onset of puberty depends strongly upon BCS. There may be clear benefit in breeding November-born animals if, during the prepubertal period, they can be maintained with a high BCS