• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1133-1139
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• 2015

This study aimed to determine the effects of parenteral selenium (Se) and vitamin E supplementation on economic impact, milk yield, and some reproductive parameters in high-yield dairy cows in the dry period and in those at the beginning of lactation. At the beginning of the dry period, cows (n = 323) were randomly divided into three groups as follows: Treatment 1 (T1), Treatment 2 (T2), and Control (C). Cows in group T1 received this preparation 21 days before calving and on calving day, and cows in group T2 received it only on calving day. The cows in the control group did not receive this preparation. Supplementation with Se increased Se serum levels of cows treated at calving day (p<0.05). Differences in milk yield at all weeks and the electrical conductivity values at the 8th and 12th weeks were significant (p<0.05). Supplementation with Se and Vitamin E decreased the incidence of metritis, the number of services per conception and the service period, but had no effects on the incidence of retained fetal membrane. A partial budgeting analysis indicated that Se supplementation was economically profitable; cows in group T1 averaged 240.6$ per cow, those in group T2 averaged 224.6$ per cow. Supplementation with Se and Vitamin E has been found to increase serum Se levels, milk yield, and has positive effects on udder health by decreasing milk conductivity values and incidence of sub-clinical mastitis.

• Asian-Australasian Journal of Animal Sciences
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• 제29권12호
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• pp.1682-1687
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• 2016

The objective of this study was to estimate the genetic parameters of milk protein yields in Iranian Holstein dairy cattle. A total of 1,112,082 test-day milk protein yield records of 167,269 first lactation Holstein cows, calved from 1990 to 2010, were analyzed. Estimates of the variance components, heritability, and genetic correlations for milk protein yields were obtained using a random regression test-day model. Milking times, herd, age of recording, year, and month of recording were included as fixed effects in the model. Additive genetic and permanent environmental random effects for the lactation curve were taken into account by applying orthogonal Legendre polynomials of the fourth order in the model. The lowest and highest additive genetic variances were estimated at the beginning and end of lactation, respectively. Permanent environmental variance was higher at both extremes. Residual variance was lowest at the middle of the lactation and contrarily, heritability increased during this period. Maximum heritability was found during the 12th lactation stage ($0.213{\pm}0.007$). Genetic, permanent, and phenotypic correlations among test-days decreased as the interval between consecutive test-days increased. A relatively large data set was used in this study; therefore, the estimated (co)variance components for random regression coefficients could be used for national genetic evaluation of dairy cattle in Iran.

• 한국초지조사료학회지
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• 제33권4호
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• pp.319-326
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• 2013

본 연구결과 조농비가 다른 사료를 각각 급여한 젖소에서 임신초기의 유방 크기는 HF군이 LF군 보다 2.4배 가량 유의하게 컸으나, 임신중기와 착유기 동안에는 두 군 간에 차이가 없었다. Estradiol의 혈중농도는 두 군 모두 사춘기부터 서서히 증가하여 임신기간 동안 사춘기의 2~3.5배가량이 되었으며, 두 군간 유의한 차이는 나타나지 않았다. 착유기 전 기간에 걸쳐서도 estradiol의 농도는 두 군간 차이가 없었다. Progesterone의 혈중 농도는 사춘기부터 증가하기 시작하여 임신중기까지 두 군 모두 비슷한 농도로 유지되었으며, 시험 전 기간에 걸쳐 두 군간 유의한 차이는 없었다. 산유량 4% FCM은 두 군 모두 분만 후 증가하다 LF군은 분만 100일, HF군은 150일을 기점으로 감소하였다. 그러나, 분만 후 50일까지를 제외하고 그 후 전 기간에 걸쳐 양질 조사료 함량이 높은 사료를 급여한 HF군의 젖소에서 산유량이 유의하게 높았으며, 분만 250일 까지도 높은 산유량을 유지하였다. 우유 내 체세포 수는 분만초기를 제외하고 착유기 전 기간 동안 HF군에서 유의하게 감소하였다. 유지율은 분만 후 비유 초기에 LF군에서 다소 높게 나타났으나, 그 이후부터는 두 군간 차이가 없었으며, 그밖에 우유 내 단백율, 고형율, MUN 모두 두 군간 차이는 관찰되지 않았다. 산유량과 체세포 수 및 유지율을 기초로 계산한 유대에 있어 HF군이 LF군에 비하여 최고 141.5% 증대되었다. 본 연구결과로부터 젖소의 양질 조사료의 함량을 적당 수준으로 증가시킴으로써 유방의 크기나 관련 호르몬의 변화 없이 우유의 생산량을 증대시키고 우유의 질을 높일 수 있을 것으로 평가되었다.

• Journal of Animal Science and Technology
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• 제56권3호
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• pp.11.1-11.9
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• 2014

This study was conducted to evaluate the effects of dietary conjugated linoleic acid (CLA) on the performance of lactating sows and piglets as well as the immunity of piglets suckling from sows fed CLA. Eighteen multiparous Duroc sows with an average body weight (BW) of $232.0{\pm}6.38kg$ were randomly selected and assigned to two dietary treatments (n = 9 for each treatment), control (no CLA addition) and 1% CLA supplementation. For the control diet, CLA was replaced with soybean oil. Experimental diets were fed to sows during a 28-day lactation period. Litter size for each sow was standardized to nine piglets by cross-fostering within 24 hours after birth. Sow milk and blood samples were taken from sows and piglets after 21 and 27 days of lactation, respectively. Loss of BW was significantly (p < 0.05) higher in sows fed control diet compared to sows fed CLA diet. Piglet weights at weaning and weight gain during suckling were significantly (p < 0.05) higher in sows fed CLA compared to sows fed control diet. Serum non-esterified fatty acid (NEFA) and urea nitrogen concentrations were significantly (p < 0.05) lower in sows fed CLA than in sows fed soybean oil. IgG concentrations of the groups supplemented with CLA increased by 49% in sow serum (p < 0.0001), 23% in milk (p < 0.05), and 35% in piglet serum (p < 0.05) compared with the control group. Sows fed CLA showed an increase of 10% in milk yield compared with sows fed soybean oil (p < 0.05), even though there was no difference in daily feed intake between the treatments. Milk fat content was significantly (p < 0.05) lower in sows fed CLA than in sows fed soybean oil. Solid-not-fat yield was significantly (p < 0.05) higher in sows supplemented with CLA than in sows fed control diet and also protein-to-fat ratio in milk was significantly (p < 0.05) higher in sows fed CLA compared with the control group. The results show that CLA supplementation to sows increased milk yield without losing BW during lactation, whereas soybean oil supplementation resulted in severe BW loss.

• Journal of Animal Science and Technology
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• 제48권1호
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• pp.9-14
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• 2006

본 시험은 유질에 영향을 미치는 체세포수에 대하여 영향을 미칠 것으로 생각되는 면역물질에 대한 환경효과와 유전모수를 추정하고자 축산연구소에서 사육하고 있는 착유우를 공시하여 이들의 혈액과 우유 시료를 채취하여 조사 분석하였다. 분만산차는 체세포수와 호중구에 영향을 미치는 것으로 나타났고(p<0.01), 비유기는 체세포수와 IgG, 호중구에 영향을 미치는 것으로 나타났다. 하지만 코티솔과 림프구는 산차와 유기에 의하여 영향을 받지 않는 것으로 나타났다. 체세포수의 산차간 비교에서 1, 2, 3 산차간에는 차이가 없었으나 4산차 이상에서는 높아지는 경향이 있어 3산차 이하와 비교 할 시에 유의적인 차이가 있었고 유기별 비교에서는 비유초기(90일 이하)와 비유후기(181일 이후)가 비유중기(91～180) 보다 높게 나타났다. 코티솔은 체세포수의 산차 성적과 마찬가지로 3산차 이하와 4산차 이상 간에 차이가 있었고 비유기별 성적에서는 높아지는 것처럼 보이나 차이는 없었다. 면역물질인 IgG는 1산차와 4산차 이상의 비교에서만 차이가 있었고 유기에서는 비유 초기가 비유 중기와 후기에 비하여 높은 결과를 보였고 림프구는 1산차와 4산차 이상 간에 차이가 있었으나 유기간에는 차이가 없었다. 호중구는 산차가 증가할수록 감소하는 경향으로 2산차 이하와 3산차 이상간에 차이가 있었으며 비유중기 까지는 차이가 없었고 비유 후기에는 높게 나타났다. 체세포수의 유전력은 낮은 수준이지만 유질 개량을 위하여 의미 있을 정도로 높게 추정되었으며 코티솔, 림프구와 부의 높은 유전상관을 보였다. 코티솔의 유전력은 비교적 낮은 수준이었고 림프구, 호중구간의 정의 상관관계를 보였다. IgG의 유전력은 중 정도를 보였으며 림프구와 호중구와는 높은 부의 유전상관을 보였다. 림프구는 높은 유전력을 보였고 호중구와도 높은 유전적 상관을 보였다. 호중구는 체세포수와 비슷한 수준의 유전력을 나타내었다. 이상의 연구 결과에서 코티솔, IgG, 림프구, 호중구가 체세포수와 유전적으로 높은 상관관계를 가지고 있어 우유 품질 개선에 중요한 형질임을 알 수 있었다. 또한 농가의 사육규모가 증가하고 두 당 생산성이 더욱 증가함에 따라 생산성과 질병을 동시에 고려하는 젖소개량 관련 연구가 수행되어야 할 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제28권11호
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• pp.1558-1564
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• 2015

Cutaneous evaporative heat loss in Bos indicus and Bos taurus has been well documented. Nonetheless, how crossbreds with different fractional genetic proportions respond to such circumstances is of interest. A study to examine the physiological responses to cutaneous evaporative heat loss, also lactation period and milk yield, were conducted in Sahiwal (Bos indicus, n = 10, $444{\pm}64.8kg$, $9{\pm}2.9years$), Holstein Friesian (Bos taurus, HF100% (n = 10, $488{\pm}97.9kg$, $6{\pm}2.8years$)) and the following crossbreds: HF50% (n = 10, $355{\pm}40.7kg$, $2{\pm}0years$) and HF87.5% (n = 10, $489{\pm}76.8kg$, $7{\pm}1.8years$). They were allocated so as to determine the physiological responses of sweating rate (SR), respiration rate (RR), rectal temperature (RT), and skin temperature (ST) with and without hair from 06:00 h am to 15:00 h pm. And milk yield during 180 days were collected at days from 30 to 180. The ambient temperature-humidity-index (THI) increased from less than 80 in the early morning to more than 90 in the late afternoon. The interaction of THI and breed were highly affected on SR, RR, RT, and ST (p<0.01). The SR was highest in Sahiwal ($595g/m^2/h$) compared to HF100% ($227g/m^2/h$), and their crossbreds both HF50% ($335g/m^2/h$) and HF87.5% ($299g/m^2/h$). On the other hand, RR was higher in HF87.5% (54 bpm) and both HF100% (48 bpm) and HF50% (42 bpm) than Sahiwal (25 bpm) (p<0.01). The RT showed no significant differences as a result of breed (p>0.05) but did change over time. The ST with and without hair were similar, and was higher in HF100% ($37.4^{\circ}C$; $38.0^{\circ}C$) and their crossbred HF50% ($35.5^{\circ}C$; $35.5^{\circ}C$) and HF87.5% ($37.1^{\circ}C$; $37.9^{\circ}C$) than Sahiwal ($34.8^{\circ}C$; $34.8^{\circ}C$) (p<0.01). Moreover, the early lactation were higher at HF100% (25 kg) and 87.5% (25 kg) than HF50% (23 kg) which were higher than Sahiwal (18 kg) while the peak period of lactation was higher at HF100% (35 kg) than crossbreds both HF87.5% and HF50% (32 kg) which was higher than Sahiwal (26 kg) (p<0.05). In conclusion, sweating and respiration were the main vehicle for dissipating excess body heat for Sahiwal, HF and crossbreds, respectively. The THI at 76 to 80 were the critical points where the physiological responses to elevated temperature displayed change.

• 농업과학연구
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• 제40권4호
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• pp.333-338
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• 2013

Sources of energy and rumen undegradable protein (RUP) have been used to meet nutrient requirements for high producing dairy cows. However studies for manipulation the levels of energy and RUP in diets have been mainly achieved using dairy cows at early-lactation period. The objective of this study thus, was to investigate the effects of different energy and rumen undegradable protein (RUP) levels on dry matter intake and milk yield in Holstein cows at mid-lactation period. Basal diet was prepared as TMR to meet nutrient requirements for dairy cows at mid-lactation according to NRC recommendation. Cows of control group (Con) were fed only basal diets while ground corn (0.5 kg/d), heat-treated soybean meal (0.5 kg/d), and their mixture (0.25 kg of each supplements/d) were added to diets for cows of treatment groups (T1, T2, and T3 respectively) to modulate the level of energy and RUP contents in diets. Addition of energy or RUP source in basal TMR did not affect in total DMI while TMR intake tended to be higher in Con compared to T3. Cows fed T3 diets tended to show increased milk yield and MUN content than those of Con. Cows for T2 as well as T3 had lower ADG (P<0.05) compared with those of Con. We concluded that the addition of RUP source in diets for dairy cows on mid-lactation period might cause the decrement of DMI and ADG.

• Asian-Australasian Journal of Animal Sciences
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• 제13권10호
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• pp.1347-1352
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• 2000

The objectives of the study were to examine non-genetic factors that influence somatic cell counts in dairy cattle and to estimate the genetic parameters of somatic cell counts. A total of 34, 097-test day somatic cell count records were obtained from the Zimbabwe Dairy Services Association (ZDSA). The data were from 5, 615 Holstein daughters of 390 sires and 2, 541 dams tested between May 1994 and December 1998. First lactation cows contributed 22, 147 records to the data set, while 11, 950 records were from second and later parity cows. The model for analysis included fixed effects of month of calving, year of calving, stage of lactation, calving interval and test date. Milk yield and age on test day were fitted in the model as covariates. The additive genetic effects pertaining to cows, sires and dams and the residual error were the random effects. The Average Information Restricted Maximum Likelihood algorithm was used for analysis. The heritability of somatic cell scores was low at $0.027{\pm}0.013$ for parity one cows and $0.087{\pm}0.031$ for parity two and above. Repeatability estimates were $0.22{\pm}0.01$ and $0.30{\pm}0.01$ for the two lactation groups, respectively. Genetic and phenotypic correlations between the somatic cell scores and test day milk production were small and negative. It seems that there is no genetic link between somatic cell counts and milk yield in Holstein cattle in Zimbabwe. The results also seem to indicate that somatic cell count is a trait that is mainly governed by environmental factors.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1415-1421
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• 2006

Proper nutritional management during the dry period is required to prevent metabolic disorders during the time of parturition and for potential increase milk yield during early lactation, especially under the heat of summer. The effect of prepartum diets on partitioning of nitrogen (N), calcium (Ca), phosphorus (P), magnesium (Mg) and potassium (K) during dry period and early lactation in summer was investigated. Nine cows were assigned to two groups and fed either control (group C: four cows) or high concentrate (group H: five cows) diets to meet 110% of their requirements before parturition. The proportion of concentrate in control diet was 35%, and that in the high concentrate diet was 45%. After parturition, all cows were fed the same diets ad libitum during lactation. Balance trials were conducted at 9, 8 and 7 days before parturition and at 12, 13 and 14 days after parturition. Before parturition, dry matter intake (DMI), DM and NFE digestibility in group C tended to be lower than those in group H. The retention of N (p<0.01) and P (p<0.05) in group C during the dry period was significantly lower than those in group H. The retention of Mg in group C during the dry period tended to be lower than in group H. The concentration of plasma NEFA in group C tended to be higher than in group H during dry period. The prepartum diet did not have an apparent effect on DMI and milk yield at 2 weeks after parturition and N, Ca, P, Mg and K balance after parturition.

• Asian-Australasian Journal of Animal Sciences
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• 제31권10호
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• pp.1542-1549
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• 2018

Objective: Because lactation periods in dairy cows lengthen with increasing total milk production, it is important to predict individual productivities after 305 days in milk (DIM) to determine the optimal lactation period. We therefore examined whether the random regression (RR) coefficient from 306 to 450 DIM (M2) can be predicted from those during the first 305 DIM (M1) by using a RR model. Methods: We analyzed test-day milk records from 85,690 Holstein cows in their first lactations and 131,727 cows in their later (second to fifth) lactations. Data in M1 and M2 were analyzed separately by using different single-trait RR animal models. We then performed a multiple regression analysis of the RR coefficients of M2 on those of M1 during the first and later lactations. Results: The first-order Legendre polynomials were practical covariates of RR for the milk yields of M2. All RR coefficients for the additive genetic (AG) effect and the intercept for the permanent environmental (PE) effect of M2 had moderate to strong correlations with the intercept for the AG effect of M1. The coefficients of determination for multiple regression of the combined intercepts for the AG and PE effects of M2 on the coefficients for the AG effect of M1 were moderate to high. The daily milk yields of M2 predicted by using the RR coefficients for the AG effect of M1 were highly correlated with those obtained by using the coefficients of M2. Conclusion: Milk production after 305 DIM can be predicted by using the RR coefficient estimates of the AG effect during the first 305 DIM.