Relationships between udder and milking traits in Murciano-Granadina dairy goats

Abstract

Morphological traits of the udder and their relationships with daily milk yield, residual milk and machine milk flow characteristics were studied in 33 Murciano-Granadina dairy goats. Measures were recorded at the start and the middle of lactation. Effects of the rearing system of kids (natural or artificial), lactation stage, parity and prolificacy were studied. Mean values and standard errors for udder traits were: teat angle, 26.8 ± 0.8°; teat-floor distance from ground, 25.0 ± 0.6 cm; teat length, 28.5 ± 0.7 mm; teat surface measured at a constant diameter, 5.2 ± 0.3 cm 2, or at a constant length, 10.9 ± 0.5 cm 2; and udder volume, 2.1 ± 0.1 l. Effects of prolificacy on udder volume and teat-floor distance were observed, goats with twins showing the largest udder volume and the shortest distance. Udder volume was positively correlated with body weight ( r = 0.80) and milk yield ( r = 0.69). Positive correlations between teat length and milk flow rate ( r = 0.55) and between teat surface, measured either at a constant length ( r = 0.47) or at a constant diameter ( r = 0.58) and residual milk were also found. Longer teat cup liners are needed to avoid compression and pain of teat tissue during milking and to reduce residual milk. With the exception of teat length, teat surface measured either at a constant diameter or at a constant length and udder volume, udder traits neither affected milk production nor milking time or flow rate. It was concluded that Murciano-Granadina dairy goats used have an appropriate udder for machine milking and longer liners (>120 mm) are recommended for this breed.