한우 포유모우의 산유량및 유조성분에 관한 연구 1 . 포유모우의 산유량 추정방법 확립에 관한 연구 = Studies on Milk Yield and Milk Composition of Korean Native Cows 1 . Studies on establishment of the estimating method of dam's milk yield

다국어 초록 (Multilingual Abstract)

This experiment was conducted to establish the estimating of dam`s milk producing capacity which forms the basis of Korean Native Cattle improvement for 3 years from 1982 to 1984. Four methods, including weight difference of the calf before and after nursing, hand milking and machine milking were compared with a new milking while the calf nurses, which the good points from the existing methods were extracted and then were developed. Fifty nine heads of nursing cow were tested to investigate dam`s milk yield. dam`s milk composition by the new milking method for 3 years from 1985 to 1987. The results of this experiment are summarized as follows: 1. This new method was made to use a portable vacuum·operated bucket milker in two quarters of each cow`s left or right udder while the calf suckles two quarters of his or her dam`s right or left udder. On this method. cows and calves were seperated at 8:00 am and at 5:00 pm the calves allowed to nurse. Cows and calves remained seperated over night. At 8:00 am and 5:00 pm the following day, the calves allowed to nurse one udder half while the rest was milked by machine. 2. On the comparison with methods estimating dam`s milk yield, the method by calf-weight difference before and after nursing wasn`t exact and good method in estimating dam`s milk yield and composition because not only this method was indirectly estimated by calf`s weight gain but also milk sample could not be taken. And also, the method by hand milking and machine milking could be surveyed only 60 days and 4 to 10 days, respectively, because dam`s milk yield was rapidly decreased with passing the milking day. However, by the new method, milking could be completely done without failure for 180 days and samples for analyzing the milk composition could be taken more easily and exactly than any other method. 3. Daily average and total milk yield of fifty nine heads investigated by this new method for 180 days was 3.48 and 625.8kg, respectively. 4. In the milk composition, total solids, far, protein, lactose and ash content was 14.21, 4.64, 4.07, 4.21 and 0.89 percent, respectively.