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The reproductive activity of 84 female Blanca Andaluza goats was monitored over 17 months to determine the role of body condition score (BCS) and body weight (BW) in its control. Following a 3x2 factorial experimental design, the animals were allocated to three groups: low BCS (≤2.50, n=24), medium BCS (BCS=2.75-3.00, n=31) and high BCS (≥3.25, n=29). The same animals, irrespective of their BCS group membership, were also divided into two groups depending on their BW: low BW (≤40 kg, n=44) and high BW (>40 kg, n=40). Oestrus was tested daily using vasectomized males. The ovulation rate was assessed by transrectal ultrasonography after the identification of oestrus. Ovulatory activity was determined by monitoring the plasma progesterone concentration weekly. BCS and BW were recorded once a week and their nutrition adjusted to maintain the initial differences between the groups. Both BCS and BW had a significant (at least P<0.05) influence on the onset, the end, and the duration of the breeding season, with longer periods of reproductive activity recorded in does with a BCS of ≥2.75 and BW of >40kg. No significant interaction between these variables was observed. Some 11.7% of the does in the groups with animals of BCS≥2.75 showed ovulatory activity during seasonal anoestrus. None of the does with a BCS of ≤2.5 showed this. The ovulation rate of the first and last oestrous was modified by BW (P<0.01). These results demonstrate that Blanca Andaluza goats show marked reproductive seasonality that is clearly and independently modulated by BCS and BW.

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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.

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