INFLUENCE OF SEASON ON SERUM PROFILES OF SOME NUTRITIONAL METABOLITES DURING THE OESTRUS CYCLE IN SAVANNAH BROWN GOATS

Résumé

The study was carried out to determine the effect of seasonal changes and oestrous cycle phase on serum levels of some nutritional metabolites in Savanna Brown (SB) goats. Twenty multiparous (n = 20) and cycling SB goats aged between 2-5 years (2-4 parity) and body mass index (BMI) of 20.17 ± 0.2 kg and 6.2±0.4 were used for the study. Ten animals were used per season. In each season, the animals were synchronized to the oestrus with a single injection of 7.5 mg PGF (Lutalyse). The animals were bled by jugular venipuncture for glucose, cholesterol and total protein determination of serum during the first oestrous cycle following treatment with PGF2. Blood sampling was done at d 0 and d 1 of the induced oestrus, twice weekly subsequently, and finally on d 0 and d lof the second estrus after PGF, treatment. The mean serum glucose concentration was higher (P < 0.05) in the cold-dry (4.3±0.1 mmol/L.) than in early rainy (3.8 ± 0.1 mmol/L) season cycles. The mean serum cholesterol concentration was significantly higher (P < 0.05) in the early rainy (3.7 ± 0.1 mmol/L) than in cold-dry (3.2±0.1 mmol/L) season cycles. There was no significant difference in mean serum total protein concentrations between the cold-dry and early rainy season cycles (cold-dry season: 64.6 +0.8 g/L vs early rainy season: 66.2±0.7 g/L; P>0.05). It is concluded that season but not oestrous cycle phase affects serum concentrations of some nutritional metabolites during the oestrous cycle in SB goats. It is therefore recommended that producers and clinicians should take into cognizance the seasonal variation in serum profiles of some energy substrates in feed formulation and reproductive herd health management in SB goats in the Northern Guinea Savannah zone of Nigeria. Keywords: Nutritional metabolites. Oestrous cycle, Season, Savannah Brown goats