Correlation between mammary gland morphology and gland cistern size to lactation milk yield in goat

Abstrakt

The studies involved 18 goats of White Improved and Saanen breed managed under the same breeding conditions. The measurements were taken once from an immobilized animal in
the 4^th lactation month, 2 hr before milking. The goats from breed groups were of the same age (third and fourth lactations). The following udder zoometric measurements were performed: udder floor length, width, depth, vertical semi-circumference, horizontal circumference, distance from the ground (milking stall), teat length, diameter, distance between teats. Besides, US measurements of gland cisterns were made. Correlation coefficients were calculated between the performed udder zoometric measurements and ultrasonographical ones of milk cisterns and daily milk production on the measurement day and throughout the lactation period. The studies showed that Saanen goat udders had greater depth, vertical semi-circumference, horizontal circumference as well as longer, wider teats placed at lower distance to the ground. The gland cisterns area in Saanen goat udders averaged 56.6 cm² and was higher by 21% as compared to White Improved breed goat group. Vertical semi-circumference, horizontal circumference and diameter of teats exhibit a strict correlation to daily milk yield (correlation coefficients were r = 0.65, r = 0.57, r = 0.48, respectively). The relationship between gland cisterns area and udder measurements showed positive, highly statistically significant correlations to depth, vertical semi-circumference and horizontal circumference, while a negative high significant dependence was noted between the
cistern size and udder distance to the ground. The correlation of both cisterns size to lactation milk yield was r = 0.46.