Variations in serum metabolites in response to season, cyclicity, and pregnancy in estrus-synchronized Damascus goats

The current study was carried out to determine the changes in serum electrolytes, liver enzymes, and hormones during breeding and non-breeding seasons in estrus-synchronized goats. Forty goats (n = 40) were synchronized by inserting the sponges intravaginally for 12 days; PMSG and PGF₂α were injected on day of sponge removal. Blood samples were collected from the goats at the time of sponges insertion (day -12), estrus day (day 0), and at 15 day after sponge withdrawal (day 15). The blood samples were analyzed for glucose, cholesterol (CHO), aspartate aminotransferase (AST), alanine aminotransferase (ALT), thyroid stimulating hormone (TSH), triiodothyronine (T₃), thyroxine (T₄) and progesterone (P₄), calcium (Ca), phosphate (PO₄), magnesium (Mg), sodium (Na), potassium (K), and chlorine (Cl) levels. Repeated measurements ANOVA of general linear model were used as statistical model. The results showed that seasons have an effect (p < 0.05) on glucose, Ca, Na, K, Cl, CHO, T₃, and T₄ levels. There was an effect (p < 0.05) of cyclicity only on P₄ level. Whereas, nonpregnant, or goats carrying singlet and twin fetuses have shown variation (p < 0.05) in glucose, Ca, and P₄ levels. Although, the correlations existed between different serum metabolites but strong correlations (p < 0.05) were observed either between Ca and Na or T₃ and T₄. In conclusion, the serum electrolytes and liver enzymes are correlated with hormones during the different seasons, pregnancy status, and fecundity. In recommendation, the results of the study could be as managemental tool to monitor the reproductive activity across seasons and to maintain pregnancy carrying twining in goat breeds.