Response of Balady dairy goats to dieltary propylene glycol and rumen - protected methionine supplementations

An 8-week trial was designed in order to study the response of lactating Balady goats to dietary supplementation with propylene glycol and rumen-protected methionine. A total of 18 healthy Balady goats were randomly divided into 3 equal groups: Group I acted as a control group that received the basal diet only; group II goats were fed the basal diet and each goat was fed 50 g of propylene glycol [PG] and goats in group III were fed the basal diet and each goat was fed 5 g of rumen-protected methionine [RPM]. All goats were in their early lactation period. Criteria used to measure the response were plasma glucose, NEFA [nonesterified fatty acids], triglycerides, cholesterol, milk composition, milk concentration of Ca, P, Na, K, Mg, Zn and Cu. The same mineral profile was also measured in plasma in addition to Fe. Blood glucose level was significantly higher in the PG-supplemented goats over the control and RPM-supplemented groups. NEFA levels were also significantly lower in the PG-supplemented and RPM-supplemented goats than the control ones. However, blood triglycerides and cholesterol levels were not affected by either of the dietary supplementation. Regarding milk composition, the RPM-supplemented group exhibited a significant increase in milk protein% over the control and PG-supplemented goats during the first 6 weeks of supplementation. No other differences were observed in milk composition. There were no significant differences between the three groups regarding the measured mineral profile. The results suggested that both propylene glycol and rumen-protected methionine can be used as dietary supplemented in Balady goats to improve their lactation performance