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《黑龙江畜牧兽医》2016,(15)
为了从泌乳曲线角度量化不同胎次和产犊季节的差异,试验利用奶牛群体改良(DHI)记录和Wood模型,拟合北京地区代表性牛场的荷斯坦奶牛泌乳曲线,并对泌乳曲线参数进行分析。结果表明:Wood模型拟合群体泌乳曲线拟合度(R2)变化范围为0.948 9~0.976 9,极显著受到胎次影响(P0.01);达到产奶高峰的速度极显著受到胎次影响(P0.01);高峰后产奶量的下降速度极显著受到产犊季节的影响(P0.01);高峰泌乳月和泌乳持续力都极显著受到胎次的影响(P0.01),显著受到产犊季节的影响(P0.05);泌乳潜力和高峰产奶量都极显著受到胎次、产犊季节及其互作的影响(P0.01)。说明泌乳曲线具有群体特异性,增加数据量制作不同产犊季节和胎次的标准泌乳曲线,以量化季节对个体和群体产奶性能的影响、预测产奶量实属必要。 相似文献
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为了比较新疆农七师荷斯坦牛不同模型泌乳曲线拟合效果,以该师奶牛场2004年3月~2009年10月间656头中国荷斯坦牛9 426个完整泌乳记录为基础,应用Wood不完全伽玛函数模型、Nelder逆多项式模型、Wilmink模型3个数学模型,对第1胎、第2胎、第3胎和第4胎及所有胎次的泌乳曲线进行了拟合。结果显示,利用Nelder逆多项式模型拟合泌乳曲线,其拟合度(R2)为0.1271～0.9431;利用Wilmink模型拟合泌乳曲线,其拟合度(R2)为0.8944～0.9471;利用Wood模型拟合泌乳曲线,其拟合度(R2)为0.8948～0.9475。结果表明,农七师荷斯坦牛泌乳曲线最佳拟合模型为Wood模型。 相似文献
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新疆褐牛产奶量校正系数的制定 总被引：2，自引：0，他引：2
为了制定新疆褐牛产奶量校正系数,收集了新疆褐牛17 962条月测定记录。采用5个数学模型(Wood不完全伽玛函数模型、Nelder逆多项式模型、多项式回归模型(六次)、Ali-Schaeffer模型和Wil mink模型)通过SAS(8.1)软件的非线性过程(NLIN)对泌乳曲线进行拟合。结果表明:5个模型的拟合度R2在0.834 0～0.921 4,确定逆多项式模型为新疆褐牛泌乳曲线最佳拟合模型,绘制了不同胎次的泌乳曲线,制定了一套不同胎次的泌乳天数产奶量校正系数。结果提示,新疆褐牛泌乳高峰日出现在20～50 d,第一胎泌乳高峰值最低,第三胎泌乳高峰日来得最早;随胎次的增加,母牛产奶量不断提高,在第五胎达到最高,以后逐渐下降,平均305 d产奶量为4 445.3kg。 相似文献
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[目的]为了研究不同产犊季节对荷斯坦奶牛第一胎泌乳性能的影响,以便为长江中下游地区荷斯坦奶牛合理安排配种时间提供科学依据。[方法]利用海丰奶牛场有限公司2009年引进2480头澳系进口荷斯坦牛产犊季节及其第一胎泌乳性能的数据,分析不同产犊季节对第一胎泌乳天数、全泌乳期实际产奶量、305d校正奶量、305d脂肪产量和305d蛋白产量的影响。[结果]表明:不同产犊季节对第一胎泌乳天数和全泌乳期产奶量影响极显著(P0.01),显著影响305天脂肪产量(0.01P0.05),春季产犊的奶牛泌乳天数最长(358±10d),而冬季产犊的奶牛泌乳天数最短(299±18d),春季与夏季产犊奶牛的全泌乳期产奶量显著高于秋季、冬季产犊奶牛(P0.05),夏季产犊奶牛305d脂肪产量最高。[结论]综合各产犊季节样本量及相应泌乳性能,认为该场澳系进口荷斯坦牛最适宜产犊季节为夏末秋初,此时泌乳性能最好。该结果对同类地区引进澳系进口荷斯坦牛繁殖与生产管理有借鉴作用。 相似文献
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不同胎次中国荷斯坦牛泌乳曲线及其拟合的初步研究 总被引：2，自引：0，他引：2
通过对扬州大学实验农牧场2000～2007年度147头中国荷斯坦牛1～5胎次(333个)完整泌乳期记录,分析了各胎次月平均产奶量和累积产奶量的变化规律,用Wood模型对月平均产奶量泌乳曲线,用线性方程、二次方程、三次方程及S型模型对累积产奶量泌乳曲线进行了拟合。结果表明:中国荷斯坦牛第1胎各泌乳月平均产奶量上升慢,泌乳高峰低,下降也慢,而第2～5胎各泌乳月平均产奶量上升快,泌乳高峰高,下降也快;各胎次累积产奶量泌乳曲线基本类似,第1、5胎产量低,2、3、4胎产量高;Wood模型对1～5胎次各泌乳月平均产奶量泌乳曲线拟合度分别为0.152、0.054、0.036、0.001、0.089;线性方程、二次方程、三次方程对不同胎次累计产奶量泌乳曲线拟合度均在0.7以上,S型模型对各胎次累计产奶量泌乳曲线拟合度均大于0.8。 相似文献
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产犊季节和胎次对荷斯坦牛部分繁殖指标的影响 总被引：2，自引：0，他引：2
为了研究不同产犊季节和胎次对荷斯坦牛部分繁殖指标的影响,为长江中下游地区荷斯坦牛合理安排配种时间提供科学依据.本试验利用海丰奶牛场引进的澳系荷斯坦牛的繁殖指标数据,分析了产犊季节和不同胎次对部分繁殖指标的影响.结果显示,产犊季节对产后第一次发情泌乳天数、配种指数、产后受孕天数以及产犊间隔等繁殖指标的影响达到极显著水平(P＜0.01).胎次对发情泌乳天数、产后受孕天数以及产犊间隔等繁殖指标的影响也达到极显著水平(P＜0.01).在本研究中,秋季产犊的奶牛繁殖指标最佳.此外,头胎产犊奶牛的繁殖性能在各胎次中最好,该结果对同类地区荷斯坦牛繁殖管理有很好的指导作用. 相似文献
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用Wood模型拟合南方中国荷斯坦牛产奶量、乳脂率、乳蛋白率和体细胞评分及其效果分析 总被引：1，自引：0，他引：1
旨在了解南方中国荷斯坦牛测定日产奶量、乳脂率、乳蛋白率和体细胞评分(Somatic cell score,SCS)变化趋势,并进行准确预测.利用Wood模型对南方5个大中型奶牛场(2008-2010年1～3胎)中国荷斯坦牛的33 194条测定日产奶量、乳脂率、乳蛋白率和SCS数据进行曲线拟合.结果表明,测定日产奶量为标准泌乳曲线,乳脂率、乳蛋白率和SCS变化与标准泌乳曲线正好相反.Wood模型对乳蛋白率和产奶量变化曲线拟合度最高,各胎次拟合度均为0.99,误差均方也较低;其次为乳脂率,各胎次拟合度均为0.98,而对SCS的拟合度最低,均在0.7以下,同时误差均方也最大.各胎次产奶高峰日出现的时间与乳蛋白率和SCS最低值出现的时间相近,而最低乳脂率出现的时间较晚.一胎牛高峰产奶量相对较低(30.4 kg·d-1),但泌乳后期泌乳持续力及维持低SCS能力较强;二胎和三胎牛高峰产奶量较大,分别为35.9和36.2 kg·d-1,二胎奶牛在泌乳后期同时维持高乳脂率和乳蛋白率的能力较强.Wood模型适合于南方中国荷斯坦牛测定日产奶量、乳脂率、乳蛋白率变化曲线的拟合分析,而不适合于SCS的拟合分析. 相似文献
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Most studies on lactation curves only consider milk yield and describe a standard lactation curve of dairy cows, showing a peak or maximum daily yield occurring between 4 and 8 weeks after calving, followed by a daily decrease in milk yield until the cow is dried off. Wood's model is a widely used lactation curve function. Wood's model was fitted to test-day records of 95,405 lactations of parities lower than 5. Milk traits were milk yield (MY), fat percentage (F%), protein percentage (P%), fat yield (FY) and protein yield (PY), and the lactation curve was individually considered as a cluster of five linked curves. Milk trait and parity influence the goodness of fit of Wood's model. In 19.3% of the lactations, the shape of the MY, FY and PY curves follows the standard lactation curve while F% and P% have the reversed standard shape. The initial phase of lactation with the FY and PY curves contributes to the high variability of shapes. 相似文献
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LIU Li-yuan ZANG Chang-jiang ZHOU Jing-hang CHEN Bao-ping GAO Pan HUANG Xi-xia ZHONG Hai-jiao 《中国畜牧兽医》2015,42(10):2707-2713
In this study,the statistical analysis data of 185 340 Holstein dairy cows daily yield records were collected from 2011 to 2014 years in Changji area of Xinjiang,five kinds of models (Wood,IQP,Wilmink,ML,AS models) were used for the first,second,third,fourth and all parities fitting lactation curve.The results showed that the Wood,IQP,Wilmink,ML,AS models fitting precision were within the range from 0.9562 to 0.9828,0.9467 to 0.9809,0.8671 to 0.9752,0.8752 to 0.9175,0.8775 to 0.9127;Milmink model was the best fitting model for the first parity lactation curve,Wood model was the best fitting model for the second,third,and fourth parities lactation curve. 相似文献
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本研究对新疆昌吉地区荷斯坦牛2011~2014年185 340条日单产记录进行统计分析,分别采用5种模型(Wood、IQP、Wilmink、ML、AS模型)对第1、2、3、4胎及所有胎次泌乳曲线进行拟合。结果表明,Wood、IQP、Wilmink、ML、AS模型拟合精度范围分别在0.9562~0.9828、0.9467~0.9809、0.8671~0.9752、0.8752~0.9175、 0.8775~0.9127范围内;Milmink模型为第1胎次泌乳曲线最佳拟合模型,Wood模型为第2、3、4胎次泌乳曲线的最佳模型。 相似文献
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W.H.M. van der Poel M.C.M. Mourits M. Nielen K. Frankena J.T. Van Oirschot Y.H. Schukken 《The Veterinary quarterly》2013,33(3):77-81
Summary The influence of Bovine Respiratory Syncytial Virus (BRSV) reinfections on the daily milk yield was studied by evaluating the milk production of 32 BRSV reinfected cows. For the estimation of milk production losses, four lactation curve models were used, including a gamma function, a second degree polynomial, and both of these models with a lag variable. Bovine respiratory syncytial virus reinfections seemed to have only a small effect on the daily milk production. Comparison of the true production with an estimated production according to the gamma function showed that the production for first lactation cows dropped 0.14 kg on average and for cows in their second or later lactation 0.56 kg on average, during 5 consecutive days in the infection period. For the second‐degree polynomial model these values were respectively 0.42 kg and 0.80 kg. All calculated average production losses were relatively small and not significant (P>0.15). The models without lag variable were more suitable than the models with the lag variable to estimate small production losses caused by BRSV reinfections. The power of this study was sufficient to detect a decrease in production of approximately 1 ‐ 1.5 kg milk per cow per day. It was therefore concluded that BRSV reinfections were not associated with an important loss of milkproduction. 相似文献
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本研究通过对北京地区1998-2016年28个场区的奶牛生产性能测定（DHI）数据进行分析,旨在比较不同产犊季节对1~3胎奶牛泌乳曲线相关参数的影响。使用Wood模型对1~3胎不同产犊季节群体和个体泌乳曲线进行拟合,并获得相应胎次下不同产犊季节奶牛泌乳曲线参数a、b、c （分别代表泌乳潜力、产奶量上升至顶峰速率、产奶量达到顶峰后下降速率）、泌乳曲线二级参数Per、PY （分别代表泌乳持续力、泌乳峰值）及305 d产奶量（305MY）。群体和个体水平的曲线拟合采用SAS 9.2中NLIN模块进行,采用混合线性模型分析不同产犊季节对各胎次奶牛泌乳曲线参数的影响。结果显示：产犊季节对Wood泌乳曲线的泌乳潜力、达到峰值的上升速率、达到峰值后的下降速率、泌乳峰值及305MY均有显著影响（P<0.05）,对于泌乳持续力没有显著影响（P>0.05）。夏季产犊牛泌乳曲线整体低于其他产犊季节,且胎次越高趋势越明显,1胎牛受到的影响较小;从胎次上分析,头胎牛泌乳持续力极显著高于经产牛（P<0.01）;头胎牛夏季产犊305MY比其他产犊季节的低274.33~490.17 kg,经产牛夏季产犊305MY比其他产犊季节的低440.76~930.68 kg。以上结果提示,北京地区牛场应注重做好经产牛和头胎牛的防暑降温工作,注意调整配种时间,避免夏季产犊牛过多,造成损失。 相似文献
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The effect of strain of Holstein-Friesian, feeding system and parity on lactation curves characteristics of spring-calving dairy cows 总被引：1，自引：0，他引：1
The purpose of the present study was to investigate the influence of strain of Holstein-Friesian (HF) cow and feeding system (FS) on the lactation curve characteristics of spring-calving cows. The Wilmink model was used to analyse the lactation curves. The three strains of HF cows compared were high production North American (HP), high durability North American (HD) and high Breeding Worth New Zealand (NZ). The three FS compared were a high milk output from pasture feed system (MP), a high concentrate feed system (HC) and a high stocking rate feed system (HS). A repeated measures model with a factorial arrangement of treatments was used to determine the influence of strain of HF, FS, parity and their interactions on the shape of the lactation curve. The curve was described based on yield at calving, the degree of ascendancy between calving and peak yield, and the persistency after peak yield. Analysis of the residuals indicated a good fit of the Wilmink curve to the data set. Strain of HF, FS, parity and the interaction of strain of HF with FS had significant effects on lactation curve characteristics. In all three FS, the HP strain achieved the highest milk production post-claving and peak yield, with the lowest persistency of lactation. In the HC system, milk production post-claving and at peak yield were higher for all three strains. Offering higher levels of concentrate supplementation to the HP strain on a pasture-based system improved their persistency of lactation. The highest persistency of lactation was achieved with NZ strain. The highest milk production post-claving and at peak and lowest persistency was achieved with third parity cows. The existence of strain by feed system interactions for lactation curve parameters clearly exhibits that the optimum system of production varies with strain of HF. 相似文献
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The objectives of this study were to estimate the environmental and additive and non-additive genetic effects on lactation curve and lactation parameters of crosses of Holstein (H), Brahman (B) and Brown Swiss (BS) in Olancho region in Honduras. The data consisted of 54,517 milk yield records from 192 dual-purpose crossbred cows lactating from 2000 to 2005 at the Universidad Nacional de Agricultura de Honduras (UNA). The lactation curve and lactation parameters of interest were the scaling factor to represent yield at the beginning of lactation (a), the factor associated with the inclining (b) and declining (c) slopes of the lactation curves, and the milk yield at initial day of lactation (MY20), peak milk yield (MYmax), day at peak milk yield (tmax), and the total milk yield (TM) per lactation, respectively. The incomplete gamma function (Wood function) was used to estimate lactation curve and lactation parameters from daily milk records of H × B, H × BS and BS × B crossbred cows. The environmental, additive and non-additive genetic effects on lactation curve and lactation parameters were estimated using Dickerson and Kinghorn models. The coefficients of determination of fitness of Wood's function (R2) ranged from 80% to 97% with an average of 93%. The lactation curve of the crossbred cows was similar to those reported for dairy cows grazing in the tropics. Lactation parameters such as MYmax, tmax and TM were significantly (P < 0.05) influenced by environmental sources of variation suggesting the necessity of differential management strategies. The moderate to large positive phenotypic correlation of MYmax and TM indicate that one of the milk yield parameters could be used as a selection criterion to improve either one or both traits. Despite the fact that both genetic models showed similar patterns, the absolute value of the parameters varied. For both models, individual additive genetic breed effect for H breed were significant (P < 0.05) and contributed more to TM than the BS breed. In the Dickerson model, highly positive significant (P < 0.01) effect on TM for H×BS and BS×B crosses was found. The Kinghorn model did not show significant effects of dominance on this parameter. The estimate of recombination effect for all crosses involving B breed were negative and significant (P < 0.05) for positive correlated lactation curve parameters. Although the inclusion of non-additive effects on crossbreeding genetic effects were not all significant for lactation curve and lactation parameters, non-additive effects should be taken into account to improve the Honduran dairy cattle production management. 相似文献
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The objective of this study was to develop a framework describing the milk production curve in sows as affected by parity, method of milk yield (MY) determination, litter size (LS), and litter gain (LG). A database containing data on LS, LG, dietary protein and fat content, MY, and composition measured on more than 1 d during lactation and method for determining MY from peer reviewed publications and individual sow data from 3 studies was constructed. A Bayesian hierarchical model was developed to analyze milk production data. The classical Wood curve was used to model time trends in MY during lactation, and it was re-parameterized expressing the natural logarithm of MY values at d 5, 20, and 30 as functional parameters. The model incorporated random effects of experiment, sow nested within experiment, and fixed effects of LS, LG, parity, and method through the functional parameters of the Wood curve. A second set of models were constructed to analyze milk composition data, including day in milk, LS, dietary protein, and fat contents. Four scenarios with different LG and LS were constructed using the framework to estimate the energy output in milk at different days during lactation. The estimated energy output was compared with energy output values calculated using the 1998 NRC method. Milk yield was underestimated by approximately 20% with the weigh-suckle-weigh technique compared with the deuterium oxide dilution technique (P < 0.001). The mean LG and LS for the dataset were 2.05 kg/d (1.0; 3.3) and 9.5 piglets (5; 14), respectively. The MY was affected by LS on d 5 and 20 (P < 0.001) and by LG on d 20 (P < 0.001) and d 30 (P = 0.004). The mean time to peak lactation was 18.7 d (SD = 1.06) postpartum and mean MY at peak lactation was 9.23 kg (SD = 0.14). The average protein, lactose, and fat content of milk was 5.22 (SD = 0.06), 5.41 (SD = 0.08), and 7.32% (SD = 0.17%), respectively. The NE requirement for lactation increased from d 5 to 20 because of increased MY. Requirements also increased with increasing LG and LS. The framework could be used to predict energy and protein requirements for lactation under different production expectations and can be incorporated into a whole animal model for determination of energy and nutrient requirements for lactating sows, which can optimize sow performance and longevity. 相似文献