BRIEF COMMUNICATION: The use of milking intervals of individual cows in assessing herd test milk production data

摘要

Herd testing is a significant expense for dairy farmers but it gives important information about individual cow yields and contributes to the genetic worth status of the cows. While every effort is made to maximise the value of the tests to the farmerthere are still opportunities to increase this value further. Estimations of milk yield from herd tests, whether from one or two milkings, rely on the generally held assumption that animals come in to the parlour in a similar order at each milking (DairyNZ 2011) and so the values obtained reflect a nominal 24 hour yield. A number of reports support this notion (Kilgour & Scott 1959; Dietrich et al. 1965; Dickson et al. 1967), but others do not (Guhl & Atkeson 1959). Systematic observations show that while this may be the case for leading and trailing cows, it is not for the rest (Soffie etal. 1976; Gadbury 1975).