Milkability of Murciano-Granadina dairy goats. Milk partitioning and flow rate during machine milking according to parity, prolificacy and mode of suckling.

Abstract

A total of 78 lactations (25 primiparous and 53 multiparous) in a herd of Murciano-Granadina dairy goats were studied over 3 years. Animals were allocated to two experimental groups: suckling (S) goats were milked once daily until weaning (week 7) and thereafter twice daily; milking (M) goats were milked twice daily from 2 d after parturition. Milk partitioning during milking (machine and machine stripping milk fractions) was recorded every week and the residual milk every 2 weeks. Milk flow rate was studied in 63 lactations on three consecutive days during week 12 or 13. Average machine and machine stripping milk fractions over 210 d were 1.09 and 0.23 l/d for the S and 1.23 and 0.28 l/d for the M group respectively. Machine milk volume and percentage were smaller in the S group during the first 7 weeks of lactation, while the machine stripping fraction was unaffected by group, indicating that this fraction was constant. The average residual milk was 11.1 and 9.2% of total milk in the S and M groups. Goats in their third lactation had the least residual milk (8.9%). Milk flow and total machine milk volume (but not milking time) were affected by parity, second and third lactation goats having higher values. Positive correlations were found between daily milk yield and milk flow characteristics. Residual milk was positively correlated with the machine stripping but not with the machine milk fraction. The results indicated that Murciano-Granadina goats can readily be machine milked, since > 80% of the milk can be obtained without massage or stripping.