• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1775-1780
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• 2001

The study was undertaken to find out the normal mean and variations in somatic cell count (SCC) of milk in crossbred and indigenous cows as influenced by stage of lactation, parity and season. On day of milk sampling the udders were tested for mastitis by California Mastitis Test (CMT). Only those cows, which were found negative in the CMT, were taken in the study. Paritywise differences in SCC were not significant between the 1st to 6th lactation and above. Similarly, stage of lactation effect, when tested at 30 day intervals, did not differ significantly. However, the seasons significantly (p<0.05) affected SCC count of milk. The SCC was lower during cold ($1.10{\times}10^5cells/ml$) and hot-dry ($1.11{\times}10^5cells/ml$) season then during hot-humid season ($2.14{\times}10^5cells/ml$). On an average SCC recorded were 1.26, 1.31, 1.54 and $1.61{\times}10^5$ cells per ml respectively in Tharparkar, Sahiwal, Karan Swiss and Karan Fries cows irrespective of stage of lactation, parity and season. Further, crossbred Karan Swiss and Karan Fries cows behave similar to the indigenous Tharparkar and Sahiwal cows but are more vulnerable to hot-humid climate then indigenous ones. Significant correlation between the SCC and milk yield during different stages of lactation (1.38 to $1.74{\times}10^5cells/ml$) and parity (1.47 to $1.63{\times}10^5cells/ml$) suggested that the SCC/ml of milk was higher during the later stages of lactation.

• Asian-Australasian Journal of Animal Sciences
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• 제17권6호
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• pp.794-798
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• 2004

An attempt was made to improve the efficiency of growth and lactation performance of dairy heifers subjected to a stair-step growth scheme using rice straw as the sole roughage source. Twenty-four young Holstein heifers were randomly assigned to either control or test group. The control diet met the National Research Council (NRC) requirement, with heifers calving at 24 to 26 mo of age. The test group was individually fed according to a schedule of 3, 2, 4, 2, 5 and 2 mo in which feed intake was alternately 20% below or 25% above the NRC requirements. Heifers on the stair-step growth pattern gained more body weight and consumed less dry matter (10.80 and 11.22%, respectively), resulting an increasing growth efficiency compared with the control. Body condition, first estrus, first conception, services per conception and calving difficulty (data not shown) were not affected. Milk yield of the test group was 8.5% higher than that of the control group. During the early lactation period, the milk yield was significantly higher in the stair-step group than in that of the control group (p<0.05). Milk composition was not affected by compensatory growth induced by the stair-step scheme. Also, weight at calving and calf growth performance was not affected by stair-step growth. The results indicate that using rice straw as a sole roughage source in a stair-step compensatory growth scheme can contribute to the improvement of growth efficiency and early lactation performance.

• Asian-Australasian Journal of Animal Sciences
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• 제28권9호
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• pp.1226-1234
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• 2015

The development of effective genetic evaluations and selection of sires requires accurate estimates of genetic parameters for all economically important traits in the breeding goal. The main objective of this study was to assess the relative performance of the traditional lactation average model (LAM) against the random regression test-day model (RRM) in the estimation of genetic parameters and prediction of breeding values for Holstein Friesian herds in Ethiopia. The data used consisted of 6,500 test-day (TD) records from 800 first-lactation Holstein Friesian cows that calved between 1997 and 2013. Co-variance components were estimated using the average information restricted maximum likelihood method under single trait animal model. The estimate of heritability for first-lactation milk yield was 0.30 from LAM whilst estimates from the RRM model ranged from 0.17 to 0.29 for the different stages of lactation. Genetic correlations between different TDs in first-lactation Holstein Friesian ranged from 0.37 to 0.99. The observed genetic correlation was less than unity between milk yields at different TDs, which indicated that the assumption of LAM may not be optimal for accurate evaluation of the genetic merit of animals. A close look at estimated breeding values from both models showed that RRM had higher standard deviation compared to LAM indicating that the TD model makes efficient utilization of TD information. Correlations of breeding values between models ranged from 0.90 to 0.96 for different group of sires and cows and marked re-rankings were observed in top sires and cows in moving from the traditional LAM to RRM evaluations.

• Current Research on Agriculture and Life Sciences
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• 제9권
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• pp.37-49
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• 1991

본 연구는 한국종축개량협회(韓國種畜改良協會)에서 1985년-1989년 사이에 일반(一般) 낙농농가(酪農農家)를 대상으로 실시한 산유능력검정자료(産乳能力檢定資料) 4,008두(頭)의 기록(記錄)을 이용(利用)하여 유우(乳牛)의 주요경제형질중(主要經濟形質中), 유량(乳量)에 관여하는 환경요인중(環境要因中) 년도(年度), 분만연령(分娩年齡), 농가(農家), 착유(搾乳) 기간효과(期間效果)를 구명(究明)하기 위하여 수행되었으며 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 일반능력(一般能力)에 있어서 각(各) 형질(形質)의 평균치(平均値) 및 표준편차(標準偏差)는 실유량(實乳量)이 $5,959.23{\pm}2,113.03kg$, 분만연령(分娩年齡) $49.19{\pm}22.77$개월(個月), 초산월령(初産月齡) $27.11{\pm}5.13$개월(個月) 그리고 착유기간(搾乳期間) $255.11{\pm}79.68$일(日)이였다. 12. 최소자승법(最小自乘法)에 의해 추정(推定)된 전체(全體) 분산(分散)에 대한 각(各) 요인별(要因別) 분산성분(分散成分)의 비(比)는 년도(年度)가 1.91%, 분만연령(分娩年齡)이 4.86%, 농가(農家)가 8.89%, 착유기간(搾乳期間)이 54.94% 그리고 오차(誤差)의 분산비(分散比)가 29.39%로 나타나 착유기간(搾乳期間)의 효과(效果)가 가장 큰 것으로 나다났다. 3. 유량(乳量)에 대한 전체의 최소자승효과(最小自乘效果) 추정치(推定値)는 6,229.31kg이였고, 년도별효과(年度別效果)에 있어서 최소자승(最小自乘) 평균치(平均値)는 1985년-1987년이 6,000.76kg, 1988년 6,028.11kg, 1989년 6,659.07kg이었다. 4. 분만연령별효과(分娩年齡別效果)에 있어서 24개월령이하(個月齡以下)는 5,456.01kg, 61-66개월령(個月齡)은 최고치인 6,565.48kg으로 분만년령간(分娩年齡間) 고도의 유의성(p<0.01)이 인정되었다. 이러한 분만연령별(分娩年齡別) 효과(效果)에 있어 24개월령이하(個月齡以下)에서부터 61-66개월령(個月齡)까지 점차 증가(增加)하다가 67-72개월령(個月齡)에 저조한 성적을 보이며 이상치를 나타냈고, 그 이후부터는 점차 감소(減少)되는 경향(傾向)을 보였다. 5. 농가별효과(農家別效果)에 있어서는 최소자승(最小自乘) 평균치(平均値)에 있어 가장 낮은 농가(農家)에서는 4,958.50kg에서 가장 높은 농가(農家)는 7,479.07kg으로 비교적 변이(變異)가 심하였고, 이는 고도(高度)의 유의성(p<0.01)이 인정되었다. 6. 착유기간별효과(搾乳期間別效果)에 있어서 착유기간(搾乳期間)이 경과(經過)함에 따라 최소자승평균치(最小自乘平均値)가 증가(增加)하는 면을 보였으며 착유기간(搾乳期間)에 따른 실유량평균간(實乳量平均間)에는 고도의 유의성이 인정되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권9호
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• pp.1196-1200
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• 2000

First lactation records of 683 Murrah buffaloes maintained at National Dairy Research Institute, Karnal, were used for comparing the sire evaluation for age at first calving, first lactation 305-day or less milk yield and first service period. The sires were evaluated using Simple daughters average, Contemporary comparison, Least-squares and BLUP methods. The BLUP evaluations were obtained under single-, two- and three-trait individual animal models. The results revealed that for taking a decision regarding the method of sire evaluation to be used for selecting sires with high breeding values, criteria of the rank correlation could be misleading and comparison of the selected sires is likely to give a veritable picture. The Best Linear Unbiased Prediction method under multi-trait animal model incorporating first lactation milk yield with first service period as a covariable and age at first calving in the model was found to be more efficient and accurate for sire selection in Murrah buffaloes.

• Journal of Animal Science and Technology
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• 제64권6호
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• pp.1013-1023
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• 2022

Body condition score (BCS) at calving is a vital indicator of the effectiveness of the beginning of lactation in dairy animals. The purpose of this study was to examine the effect of BCS at calving on milk production and transition success in dairy buffaloes. Thirty-six (36) Nili Ravi buffaloes were enrolled at 40 days of expected calving and followed through 90 days of lactation. The buffaloes were categorized into three groups according to their BCS (on a scale of 1-5 with 0.25 increments) as follows: 1) low, buffaloes with BCS ≤ 3.0; 2) medium, buffaloes with BCS 3.25-3.5; and 3) high, buffaloes with BCS ≥ 3.75. All buffaloes were fed a similar diet ad libitum. The lactation diet had increased concentrate allowance according to milk yield. The results revealed that the BCS at calving did not affect milk yield; however, fat percentage (fat%) was lower in the low-BCS group. Dry matter intake (DMI) was similar among the treatment groups, although post-calving BCS loss was greater in the high-BCS group compared to the medium- and the low-BCS groups. Similarly, the buffaloes in the high-BCS group had higher non-esterified fatty acids (NEFA) concentration compared to the low- and medium-BCS groups. No cases of metabolic disorders were observed during the study. The present results suggest that the buffaloes in the medium-BCS group appeared to perform better compared to the low- and the high-BCS groups with respect to milk fat% and blood NEFA concentration.

• Asian-Australasian Journal of Animal Sciences
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• 제11권5호
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• pp.470-474
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• 1998

Data on the first lactation performance traits of $F_1$, $F_2$ and $F_3$ crosses covering the period from 1972 to 1995 of a total of 803 dairy cows of three genetic grades maintained at Livestock Production Research Farm, Indian Veterinary Research Institute, Izatnagar were analysed. Three genetic grades were 1/2 Friesian + 1/2 Hariana (FH), 1/2 Friesian + 1/4 Brown Swiss and 1/4 Hariana (FBH) and 1/2 Friesian+ 1/4 Jersey + 1/4 Hariana (FJH). Age at first calving increased by 7% and 8% in $F_2$ and $F_3$, respectively, over the $F_1$ in FH. The reduction in age at first calving at $F_2$ and $F_3$ levels by 2-7% over the $F_1$ was observed in FBH and FJH. The lactation milk yield of $F_1$, $F_2$ and $F_3$ crosses was $1,943{\pm}100.3$, $2202{\pm}120.5$ and $1,925{\pm}123.2kg$ in FH; $2,014{\pm}76.7$, $2,264{\pm}91.5$ and $2,096{\pm}123.9kg$ in FBH and $2,005{\pm}87.0$, $2,414{\pm}94.4$ and $2,093{\pm}121.1kg$ in FJH, respectively. The lactation milk yield improved by 12-20% in $F_2$ crosses in various genetic grades. The performance of $F_1$ was, however, maintained in FH $F_3$ crosses, it improved by 4% in FBH and FJH $F_3$ crosses. The lactation lengths and calving intervals were nearly the same for $F_1$, $F_2$ and $F_3$ crosses in FH while lactation lengths and calving intervals were reduced by 3-11% in $F_2$ and $F_3$ crosses in FBH and FJH genetic grades. The milk yield/day of lactation length and milk yield/day of calving interval increased by 16-35% in $F_2$ and 2-14% in $F_3$ over the $F_1$ in various genetic grades. It is recommended that a sufficiently large effective population size of these three genetic grades be maintained by inter se matings and rigorous selection of sires so for developing a genetic base population for new breed development.

• Asian-Australasian Journal of Animal Sciences
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• 제24권9호
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• pp.1227-1232
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• 2011

The objective of this study was to examine the effects of concentrates containing different levels of a vitamin-trace elements premix on milk yield and composition of dairy cows. The trial, which lasted 14 weeks, was conducted from January to March and used 45 multiparous Brown cows in the early phase of lactation. Cows (n = 15 per treatment) were randomly allocated to three dietary treatments: the first group (control, C-0) was fed pelleted concentrate containing background vitamins and trace elements that supplied 1.0 times cows' daily requirements; the second group were fed the same concentrate, but containing 2.5 g/kg of vitamin and trace mineral premix per kg of concentrate (C-2.5); the third group were fed the same concentrate, but containing 5 g/kg of vitamin and trace mineral premix per kg of concentrate (C-5). The daily ration included ad libitum chopped oat hay, and the cows also had 8 h/d grazing on a ryegrass (Lolium multiflorum) pasture. During the performance trial, cow milk yield was daily recorded and individual milk samples were analysed for milk composition and to determine milk renneting properties. Cows fed the intermediate premix level (C-2.5) in diet showed the highest fat-corrected milk production (p<0.05) compared to other groups. None of the milk quality parameters studied were influenced by dietary treatment, except for milk rheological parameters (rennet clotting time and curd firmness) that were positively improved in cows fed the C-2.5 diet (p<0.05). The findings from this study show that intermediate level of vitamin-trace elements premix in concentrate can be advantageously used in grazing dairy cows without negative effects on yield and quality of milk produced.

• Asian-Australasian Journal of Animal Sciences
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• 제18권8호
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• pp.1125-1129
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• 2005

A study was conducted to determine the effect of feeding sugar cane silage compared to chopped whole sugar cane or grass silage on performances of lactating dairy cows during the dry season. Twenty four Holstein Friesian crossbred (>87.5% Holstein Friesian) lactating dairy cows in mid lactation; averaging 15.4${\pm}$3.2 kg of milk, 120${\pm}$23 days in milk, 50.5${\pm}$6.5 months old and 432${\pm}$39 kg live weight, were stratified for milk yield, days in milk, age, stage of lactation and body weight, and then randomly allocated to three treatment groups (8 cows in each group). All cows were fed 7.5 kg/d commercial concentrate plus ad libitum roughage according to treatment groups, which were grass silage, sugar cane silage or chopped whole sugar cane respectively. All cows consumed similar DM and produced similar milk and milk composition yields. However, cows on grass silage lost more weight than the other cows. The present study indicated that, during the dry season, sugar cane silage can be fed to lactating dairy cows, while giving similar milk yield to grass silage or chopped whole sugar cane.

• Asian-Australasian Journal of Animal Sciences
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• 제21권8호
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• pp.1088-1096
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• 2008

Data from milk performance testing were used to analyze genetic and environmental trends for purebred Tsigai, Improved Valachian and Lacaune sheep. 103,715 (Tsigai), 212,962 (Improved Valachian) and 2,196 (Lacaune) test-day records gathered by the State Breeding Institute of the Slovak Republic entered the analyses. The respective pedigree data comprised 23,724 (Tsigai), 51,401 (Improved Valachian) and 438 (Lacaune) records. The multiple-trait, mixed model methodology was used to predict the breeding values for daily milk yield, fat and protein content and to estimate the fixed and remaining random effects assumed to affect the above mentioned traits, separately for each breed. The breeding values for daily milk yield were adjusted for 150-day standardized lactation length by multiplying with the constant 150, as the breeding goal of the selection scheme in Slovakian sheep is to increase 150-day milk production and constant heritability throughout the whole lactation is assumed. The genetic trends were expressed as changes in averages of breeding values across birth years of animals. For Tsigai and Lacaune breeds, cumulative genetic changes over the analyzed period were 3.8 and 5.1 kg for 150-day milk, 0 and -0.16% for fat content and 0 and -0.12% for protein content. For Improved Valachian breed, either a low (1.6 kg for 150-day milk yield) or zero (fat and protein content) cumulative genetic change was found. The environmental trends were calculated as averages of solutions for flock-test day effect across years and months in which measurements were taken. A distinctive cyclical pattern which reflected short-time variation in milk production traits was found. Possible explanations for this phenomenon are given and discussed.