A series of experiments were carried out to determine the milk production potential and milk composition as well as physico-chemical properties in Korean cattle depending on an effective milking method. Total 620 milk samples were collected bi-weekly for 6 months post-partum from one hundred and two nursing cow-calf pairs on test for 5 year period. The $quot;machine milking while suckling$quot; method, which had been developed and eventually proved to be easiest and most effective in the experiments testing various milking methods, was adopted throughout 180 days of lactation. In this method each cow was milked by a portable vaccum-operated bucket milker on 24-hour shifts at two teats of one udder while the other two teats were being suckled simultaneously by her calf.
The average daily and total 180-day yield of dams were 3.49 and 627.5㎏ , respectively, although considerable individual variations in daily production existed ranging from 1.60 to 6.20㎏ . The average daily yield measured at 30 day intervals for the first six months after calving were 4.73, 4.34, 3.70, 3.21, 2.73 and 2.20㎏ , respectively. In general, the peak lactation was attained about 10th day after calving with its average coming up to 5.l㎏ . The milk production decreased thereafter by 0.017㎏ per day throughout the rest of the lactation, exhibiting a quite linear decline with the gradient of 4.94% every 10 day period.
The physico-chemical properties such as specific gravity, pH and acidity of total milk samples were about 1.035, 6.68 and 0.215, respectively. The concentrations of butter fat, protein, lactose, ash, total solids and solids-not-fat were 4.69, 4.10, 4.23, 0.85, 13.86 and 9.18%, respectively.
It is concluded that this new method, that is the machine milking while suckling, may be a usefull milking methods for estimating dam´s milk yield and measuring physico-chemical properities as well as for illuminating milk composition of Hanwoo. There is a wide difference in individual milk performance. If a cows of full capacity in milk production and composition is sellected by the utilization of this method and the foundation of mating system for improvement of Hanwoo is established, it may be greatly decreaed the production cost of Hanwoa calf.
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