Milk Yield


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Milk Yield

 

the amount of milk, in kilograms or liters, obtained from agricultural animals, mainly cows, sheep, and mares, during a specified period, for example, a given milking, a day, a month, a period of lactation, or the animal’s entire life. The size of milk yield depends on the type of animal, the animal’s breed, age, individual features, and period of lactation, and the conditions under which it is fed and cared for. The highest milk yields are from cows of specialized dairy breeds. As the animal grows older, its milk yields increase until the sixth or seventh lactation and then decrease. Milk yield increases in the first 1½ to two months after calving and gradually decreases after the third month. Increase in the animal’s weight to the optimum for the breed is accompanied by an increase in milk yield. Milk yield increases if the animal is milked three or four times a day; however, this entails a greater expenditure of labor.

References in periodicals archive ?
According to the results of studies focusing on the milk yield parameters of Brown Swiss and Simmental cows, the mean real milk yields of Brown Swiss cows in their first lactation periods were between 3325 kg and 6219 kg, and their mean 305-day milk yield was between 3063 kg and 6219 kg (Aktas and Bakir, 2011; Balci, 1996; Cakilli and Gunes, 2007; Cilek and Bakir, 2010; Dag et al., 2003; Inci et al., 2007; Kocak et al., 2008).
However, the parameters used in these models are not adequate for some situations, because some events, like parity number, breed, female age and feeding, can have undesired effects on the milk yield estimation (ZAMBOM et al., 2005; RODRIGUES et al., 2006).
The milk yield and composition of the Anatolian water buffaloes were checked on a monthly basis.
On the other hand, Johnson (1976) attributed that the milk yield variation was due to climatic factors is among 3-10%.
Where [y.sub.ijkl] is the milk yield of the Ith animal of the ith herdyear-season, recorded at the jth calving age and the kth DIM; HY[S.sub.i] is the effect of the ith herd-year-season (i = 1 to 2,483); [age.sub.j] is the effect of the jth calving age (j = 1 to 2); DI[M.sub.k] is the effect of the kth DIM (k = 1 to 50); [a.sub.l] and [p.sub.l] are the effects of the additive genetic merit and permanent environment of the cow l (l = 1 to 56,132); f(i) is the heat stress function for the herd-test-day (HTD); [v.sub.l] and [q.sub.l] are the additive and permanent environmental effects of heat tolerance on cow l, respectively; and [e.sub.ijkl] is the residual effect.
Correlations between fat or protein percentages and milk yield were performed on a breed-group basis (Table 2).
While a negative correlation between an increased SCC during the first month of the first lactation and longevity has been proven, suggestions to further investigation of lifetime milk yield are still to be made.
The animals were grouped according to calving order (first, second, third, and fourth calving) at different days in milk (DIM): early (1-90 DIM), middle (91-180 DIM), and end of lactation (over 181 DIM) for comparing milk yield, milk composition, and blood metabolic profile between the calving orders within the same lactation period.
The T2 and T3 differed non-significantly (p<0.05) for milk yield and composition.
The overall lactation milk yield was 2435 kg in 280 days with 3.89 % fat.
Result for simple correlation was observed low to high and positive for lactation length x milk yield, milk yield x birth weight and birth weight vs lactation length, while the genetic correlation was observed moderate to low between milk yield and lactation length and birth weight x lactation length, whereas the genetic correlation was found negative between birth weight x milk yield.