This study was conducted to estimate the growth parameters of Holstein cows and to compare their growth characteristics based on weight-age data of Holstein cows of 293 heads from National Institute of Animal Science in Korea. Three models(Gompertz, von Bertalanffy and Logistic model) were considered for analyses. The estimated growth functions for Gompertz, von Bertalanffy and Logistic models were Wt=781.0e−2900e−0.09521t,Wt=943.3(1−0.650e−0.06231t)3 and Wt=665.7(1+13.475e−0.18260t)−1 , respectively. The estimated average infection points(ti) showing maximum growth rate were 352.034, 338.181 and 430.987 day of age, respectively, using on Gompertz, von Bertalanffy and Logistic model. Average gain at inflection for Gompertz, von Bertalanffy and Logistic model were estimated 0.878, 0.833 and 0.986 kg/day, respectively. The estimated weight at inflection for Gompertz, von Bertalanffy and Logistic model were 301.5, 279.5 and 332.9 kg, respectively. In the study, the von Bertalanffy model having a variable point of inflection fitted the best for data of Holstein cows.

본 연구는 분만간격과 비유곡선 모수들 간의 상관관계를 규명하기 위하여 농협중앙회 젖소개량사업 소에서 진행하고 있는 유우군 능력검정사업에 참여하고 있는 홀스타인 젖소로부터 조사한 착유기록 36,505개를 분석하였는데, 분석에 이용된 착유기록은 모두 2011년부터 2013년 사이에 분만한 경산우 로부터 조사하였다. 비유곡선 모수는 Wood 모형을 적용하여, SAS 9.2 NLIN Procedure를 이용해 추 정하였다. 분만년도-계절(봄, 여름, 가을, 겨울)효과와 산차(2, 3, 4산차)의 효과를 고정효과로 한 다 형질 일반선형모형으로 SAS(GLM procedure)를 이용하였다. 분만간격, 305일 유량, 비유곡선모수(A, b, c), 비유지속성, Peak 일시 및 Peak기 유량에 대해 분만년도-계절과 산차의 효과는 모두 유의적 으로 나타났다(p<0.05). Wood 모형으로 추정한 비유곡선 함수는 2, 3 및 4산차에 대해 각각 yt = 24.66t0-175e-0.00302t, yt = 24.69t0-192e-0.00334t 및 yt = 24.22t0.200e-0.00341t으로 추정되었다. 분만간격과 305일 유량, 모수값 A, b, c, 비유지속성, Peak 일시 및 Peak기 유량과의 표현형상관(잔차상관)은 각 각 0.093, -0.014, 0.028, -0.046, 0.099, 0.085 및 0.052으로 나타났다. 분만간격이 길어지면 비유 곡선의 상향경사도, 비유지속성, Peak 일시, Peak기 유량은 증가하고, 비유곡선의 하향경사도는 감소 하여, 305일 유량은 증가할 것으로 판단된다.

In order to provide basic data to predict changes of milk components in milk yield, this study was conducted to compare nutritive values of diets collected from organic dairy farms (ODF) and conventional dairy farms (CDF) of Chungnam and Jeonbuk in Korea. The contents of crude fat, crude fiver, neutral detergent fiber, and acid detergent fiber in diets of ODF were significantly (p<0.05) higher compared to those of CDF. The contents of crude protein and crude ash in ODF were also higher (p<0.05) than those of CDF. The contents of calcium, ferrum, and phosphorus in diets of ODF were similar to those of CDF. The contents of potassium, magnesium, and iodine in diets of ODF were higher (p<0.05) than those of CDF. The contents of total saturated and unsaturated fatty acids in diets of ODF were higher (p<0.05) compared to those of CDF. The contents of oleic acid, linoleic acid, and linolenic acid in diets of ODF were higher (p<0.05) compared to those of CDF. However, the contents of myristic acid, palmitic acid, and stearic acid in diets of ODF were lower (p<0.05) compared to those of CDF.

A study was conducted to investigate the efficiency of recipient for Embryo Transfer (ET) in Holstein Heifers. A total of 193 heifers (Age 14-20 months and body weight, 250-400 Kg) was assigned in 2 groups (natural ovulation cycle group and Hormone-induced ovulation synchronization group) based on the development of corpus luteum (CL) and uterus where 28.49% (55/193) heifers were in normal estrous. The ET technique was applied in both of the groups to transfer the embryo in the recipients and evaluated their efficiency. In vivo frozen embryos were used for ET at the blastocyst stage. Results showed that according to recipient preparation method the conception rates were 22.72% (10/44) and 40.26% (60/149) in hormone-induced ovulation synchronization group and natural ovulation cycle group, respectively. The pregnancy rate of heifers was significantly higher (p<0.05) during the first time ET compared to repeat ET; however, recipient showed no significant difference in CL development in both side. The conception rate were 31.03% (9/29), 37.75% (57/151) and 15.38% (2/13) at day 6, 7 and 8, respectively after the CL development of the heifers. The conception rate was significantly higher (p<0.05) in the right side compared to left side of the CL development. In addition, during ET anesthesia group and non anesthesia group conception rate of the recipient were 27.63% (21/76) and 41.88% (49/117), respectively.