Composition of Milk Fat in Normal,Ketotic and Fasting Cows

By means of gas chromatography the authors have found changes in the composition of the milk fat in ketosis and after fasting, the concentration of short-chain fatty acids falling and of long-chain rising. This is interpreted as indicating that no essential difference in this respect exists between ketotic cows and cows after a period of fasting associated with hyperketonaemia. Since clinically healthy cows without hyperketonaemia likewise had a lowered concentration of short-chain and elevated concentration of long-chain fatty acids in the milk fat if they received a low-energy diet during the first weeks after calving, the authors question whether the impaired lipogenesis reported by others in primary ketosis is not a physiological consequence of fasting and therefore lacks aetiological significance for the primary ketosis.     

Increased Risk of Conception Failure in German Holstein Friesian Cows with Chronic Endometritis

The objective of this retrospective field study was to evaluate the effect of chronic clinical endometritis (CCE) on days open in German Holstein Friesian cows. Two hundred and sixty‐four cows diagnosed with CCE from day 14 to 42 postpartum were included in this study. A Cox’s proportional hazards regression model with stepwise forward selection for days open was used and the variables type of vaginal discharge, ovarian cysts and a marked loss of body condition score proved to be significant with hazard ratios of 1.5, 2.0 and 1.9 respectively. Although not remaining in the model, a weak positive effect of treatment for CCE and a negative effect of high milk production could also be found in the univariate analysis. These results suggest that the suppression of fertility of animals diagnosed with CCE varies according to the different symptoms, which could be used to support decisions regarding treatment. Management factors such as a marked loss in body condition and high milk production prolonged the number of days open of animals with CCE.     

Genetic study of fertility traits and production in different parities in Italian Friesian cattle

ZUSAMMENFASSUNG: Genetische Analyse von Fruchtbarkeits- und Produktionsmerkmalen bei italienischen Schwarzbunten in verschiedenen Laktationen Produktions- und Reproduktionsdaten von italienischen Schwarzbunten sind für die Analyse von Wechselbeziehungen zwischen den Merkmalen Zwischentragzeit, Rastzeit, Tr?chtigkeitsrate bei Erstbesamung, Anzahl von Besamungen je Tr?chtigkeit einerseits und der 305 Tage Milchleistung andererseits verwendet worden. Die Milchleistung der Kühe wurde für Laktationsnummer, Kalbealter und Zwischentragezeit korrigiert. Die Analyse wurde für die ersten drei Abkalbungen getrennt durchgeführt. Die Sch?tzwerte für die Heritabilit?t liegen für die Fruchtbarkeitsmerkmale zwischen .01 und .03 und für die Milchleistungsmerkmale zwischen .16 und .22. Für die Wiederholbarkeiten wurden Werte zwischen .02 und .08 (Fruchtbarkeit) bzw. .49 und .59 (Milchleistung) gesch?tzt. Die genetische Korrelation zwischen Milchmenge und Zwischentragezeit, zwischen Milchmenge und Rastzeit sowie zwischen Tr?chtigkeitsrate bei Erstbesamung und Anzahl Besamungen je Tr?chtigkeit betr?gt .70, .92 und -.98, resp. Zwischen Fruchtbarkeits- und Milchleistungsmerkmalen wurden generell negative Korrelationen gesch?tzt, was als Antagonismus zwischen Fruchtbarkeit und Milchleistung interpretiert werden mu?. Dies bedeutet, da? bei ausschlie?licher Selektion nach Milchleistung negative Auswirkungen bezüglich der Fruchtbarkeit der Kühe zu erwarten sind. Als m?gliche Selektionsmerkmale für die Zuchtwertsch?tzung auf Fruchtbarkeit werden Tr?chtigkeitsrate bei Erstbesamung und Rastzeit (oder alternativ Anzahl Besamungen je Tr?chtigkeit) vorgeschlagen. SUMMARY: A data set of production records with breeding information was used to analyse the relationship between open period, days to first breeding, conception rate at first service, number of services per conception and 305 day milk yield adjusted for age/month of calving and open period in the Italian Friesian Cattle Breed. Separate analyses were performed for the first three parities. Heritability estimates for reproductive traits varied from .01 to .03 and for productive traits from .16 to .22 depending on parities. Repeatabilities for fertility traits were .02 to .08 while for milk yield they were between .49 and .59. Open period and days to first service were found to be highly correlated (genetic correlation: +.70 / +.92) as were conception rate at first service and number of services per conception (-.98). An antagonistic genetic relationship was found between all reproductive traits considered and production. The magnitude of the antagonistic genetic association between production and fertility indicate that genetic deterioration of fertility is to be expected if selection pressure continues to be applied to milk production only. For multiple trait selection, the reproductive measures which complement each other are days to first service and first service conception rate (or number of services per conception).     

Repeatability and Heritability of Ovulation Number and Embryos in Dam-daughters Pairs in Superovulated Holstein–Friesian Cows

Holstein-Friesian dams (n = 28) and daughters (n = 28) were superovulated (total number of observations was 235) to determine the repeatability and heritability of ovulation number and embryo collection result for FSH treatment. The donor cows were superovulated with FSHp, artificial insemination was performed and embryo collection was carried out 7 days later. For the analysis, the raw corpdata of the number of corpora lutea (CL), the number of collected embryos (EM) and their log-transformed values were used (log CL, log EM). The genetic parameters were calculated by using the VCE4 software. For calculating heritability, the number of embryo collection was used as a random effect; for calculating repeatability, the permanent environment was fitted. The additive genetic variance of CL was 8.91 and that of the EM was 9.23. The additive genetic variance for the log CL and log EM were 0.457 and 0.340, respectively. The estimated heritability for CL and EM were 0.234 and 0.159, and repeatability were 0.386 and 0.301, respectively. Higher heritabilities but lower as the previous repeatabilities were observed for the log-transformed data, 0.266, 0.194 and 0.294, 0.208 for log CL and for log EM, respectively.     

Productive,Physiological and Biochemical Changes in Imported and Locally Born Friesian and Holstein Lactating Cows under Hot Summer Conditions of Egypt

Twenty each of healthy lactating Friesian and Holstein cows were studied. They were of similar age and body weight, nonpregnant in their third lactation and 80–100 days post partum. The investigation was carried out for 8 weeks on two farms at the same time during the hot summer season in Egypt. The first farm was in Demietta (North east of the Nile Delta, 31° 40 N) on 20 Friesian cows and the second was in Fakous (East of the Nile Delta, 30° 40 N) on 20 Holstein cows. On each of the two farms, 10 cows were newly imported and 10 were born in Egypt.The average daily milk yield and total milk production in the third lactation of the newly imported cows were significantly higher than those of the locally born cows for both Friesians and Holsteins. At the same time, the T₄, T₃, urea-N, haematological values and AST enzyme activity in the newly imported cows were significantly lower than those in the locally born ones in both breeds, while the locally born cows showed significantly lower values for rectal temperature and respiration rate, as well as for AST and Alk-P enzyme activities, than the newly imported cows of either breed.Holstein cows surpassed the Friesians in milk production, as well as thyroid hormone secretion and cholesterol, haemoglobin, packed cell volume and erythrocyte count values. The opposite was found for serum total protein, urea-N and creatinine concentrations, leukocyte count and AST, ALT and Alk-P enzyme activities.     

Plasma parameters related to energy and lipid metabolism in periparturient Modenese and Italian Friesian cows

The aim of this work was to compare energy and lipid metabolism during the peripartum period between Modenese (MO) and Italian Friesian (IF) cows. The study was carried out on 33 pluriparous pregnant cows, 19 IF and 14 MO, reared together in the same herd and kept under equal conditions of management and nutrition. Blood was sampled from jugular vein starting 4 week before expected calving date until 4 week post‐calving, once weekly. Plasma was analysed for glucose, NEFA, BHBA, triglycerides and cholesterol concentrations. Body condition score (BCS) was assessed weekly after blood sampling. Data from antepartum (a.p.) and post‐partum (p.p.) periods were separately analysed as repeated measures by a linear mixed models with the effect of breed, time and their interaction as main factors and random cow within breed. The energy status differed between the two breeds during the peripartum period. We observed higher BCS a.p. and p.p. and lower BCS variations p.p. in MO compared to IF group. Modenese cows showed lower glucose and cholesterol concentrations (p < 0.001), but higher NEFA values, NEFA to cholesterol and NEFA to albumin ratios (p < 0.001) during a.p.; on the contrary, IF cows had higher (p < 0.05) cholesterol, NEFA, BHBA levels and NEFA to albumin ratio than MO ones during p.p. The differences observed between the two breeds suggest how MO cows are subjected to lipid mobilization during late gestation; on the contrary, IF cows are predisposed to mobilize their lipid reserves at the beginning of lactation to support high production. The results indicate a diverse ability to cope with metabolic stress and suggest the hypothesis that the differences in concentrations of plasma parameters and their variation amplitude around the calving period might depend on the different genetic merit for milk production between the two breeds.     

益生菌对奶牛产奶量、乳成分及瘤胃微生物区系的影响

优质牛奶的充足供给需要以奶牛的健康养殖为基础。益生菌在奶牛饲料中的添加对奶牛的产奶量、乳成分和瘤胃微生态区系均有正面影响,可以通过增加奶牛瘤胃中有益微生物的含量,同时竞争性抑制有害菌的生长定殖,进而提高奶牛的机体健康状况和生产性能。本文对益生菌的功能、作用机制及在奶牛养殖中的应用效果进行阐述,旨在为益生菌的广泛应用提供参考。     

Pregnancy‐Associated Glycoprotein (PAG) Profile of Holstein–Friesian Cows as Compared to Dual‐Purpose and Beef Cows

Pregnancy‐associated glycoproteins (PAGs) are produced by mono‐ and binucleate trophoblast cells in the ruminant placenta. PAG appears in maternal blood and, from approximately 4 weeks after fertilization onward, may serve as a reliable means of diagnosing pregnancy. A range of factors are said to affect plasma PAG concentrations, such as number and sex of foetus, mass of calf and placenta, level of milk production and genetic constitution. In this study, PAG pregnancy profiles of a dual‐purpose (Simmental) and two beef breeds (Uckermark and Aubrac) are compared with the profile of the specialized dairy breed Holstein–Friesian. Holstein–Friesian cows were sampled weekly; the levels of the other breeds were presented at 3‐week intervals. The overall significant breed difference (p = 0.013) was founded on deviations during the initial 3 weeks of pregnancy and from 23 weeks onward. During the period critical for the detection of pregnancy, between four and 22 weeks, agreement between PAG levels of various breeds was close (p > 0.05). No significant effect of body mass of cow or calf (relative to mass of dam) was detected. These findings imply that the PAG pregnancy test may be executed uniformly irrespective of breed or type of cow, affirming the suitability of the test as a valuable asset for the cattle industry.     

荷斯坦奶牛产奶量与乳成分的相关性研究

为探讨湖北地区荷斯坦奶牛产奶量、乳成分的相关性,本研究选择2016年湖北省3个牧场的DHI数据,运用SPSS17.0中的双变量相关分析和偏相关分析,分析产奶量与乳成分的相互关系。结果表明:3个牧场产奶量与乳脂率、乳蛋白率、体细胞数、乳尿素氮呈负相关(P0.01);乳脂率与乳蛋白率、体细胞数、乳尿素氮均呈正相关(P0.01);乳蛋白率与体细胞数呈正相关(P0.01),与乳尿素氮呈负相关(P0.01);体细胞数与乳尿素氮均呈负相关(P0.01);产奶量与体细胞数简单相关系数-0.003(P0.05),偏相关系数-0.054(P0.01);体细胞数与乳尿素氮含量简单相关系数0.003(P0.05),偏相关系数-0.134(P0.01)。在产奶量与乳成分间关系研究中简单相关分析与偏相关分析结果不一致,在多个变量相关性研究中,偏相关分析更能真实反映2个变量间本质联系。     

Differences in feed intake between holstein Friesian,Dutch Red and White and Dutch Friesian cattle

In a comparison of Holstein Friesian (HF) from North America with Dutch Red and Whites (DRW) and Dutch Friesians (DF), the feed intake of 20 animals per breed was measured at different stages of lactation and at different ages. In the experiments with dairy cows, the animals were offered concentrates individually according to their milk yield. In all experiments roughage (silage or hay) was offered ad libitum.In all experiments the DRW animals ate less roughage than the HF and DF animals, although they ate the lowest amount of concentrates in nearly all experiments, due to their lower milk yield. The HF animals were offered more concentrates than the DF animals, but ate the same amount of roughage.     

Differences in mastitis susceptibility between Holstein Friesian,Dutch Friesian and Dutch Red and White cows

Summary

On an experimental farm 3 dairy breeds were compared with regard to mastitis by various parameters.

Higher cell counts and more udder infections were present in the Dutch Red and White (DRW) in comparison with the Holstein Friesian (HF) and the Dutch Friesian (DF). Within the HF breed a negative correlation between cell count and production was established and also in this breed, a negative correlation between maximum rate of milk flow and cell count.

There is no evidence that higher procuction and easier milking are connected with more mastitis. On the contrary, within the breeds an opposite trend appeared. Selection against mastitis does not conflict with selection for production and ease of milking.

An addition trial revealed that sampling after too quick preparation of the cows before milking resulted in much higher cell counts in quarter samples.

Cows which were selected for drying off with antibiotics recovered from their infection but these more susceptible animals maintained a higher cell count to a certain extent.     

Differences in mastitis susceptibility between Holstein Friesian, Dutch Friesian and Dutch Red and White cows

Summary On an experimental farm 3 dairy breeds were compared with regard to mastitis by various parameters. Higher cell counts and more udder infections were present in the Dutch Red and White (DRW) in comparison with the Holstein Friesian (HF) and the Dutch Friesian (DF). Within the HF breed a negative correlation between cell count and production was established and also in this breed, a negative correlation between maximum rate of milk flow and cell count. There is no evidence that higher procuction and easier milking are connected with more mastitis. On the contrary, within the breeds an opposite trend appeared. Selection against mastitis does not conflict with selection for production and ease of milking. An addition trial revealed that sampling after too quick preparation of the cows before milking resulted in much higher cell counts in quarter samples. Cows which were selected for drying off with antibiotics recovered from their infection but these more susceptible animals maintained a higher cell count to a certain extent.     

Cholinesterase Levels in Blood Plasma and Erythrocytes from Calves,Normal Delivering Cows and Cows Suffering from Parturient Paresis

Plasma cholinesterase (pChE) levels and erythrocyte acetylcholinesterase (eAChE) levels were studied in 6 cows before, during and after parturition (Group I), their calves (Group II), 38 cows suffering from parturient paresis (Group III) and 14 newly delivered non-paretic cows (Group IV).The mean of the pChE level in Group I was 1.5 μkat/1 ± 0.20 before parturition and decreased significantly (P ≦ 0.05) to 1.2 ukat/1 ± 0.16 after parturition. The eAChE level was before parturition ≅ 140 ukat/1 and decreased to ≅ 130 μkat/1 4–5 weeks after parturition.At birth the pChE level was 12.8 ukat/1 ± 5.9 in Group II. After 4 weeks the level had decreased to 2.3 ukat/1 ±0.3. In the bull calves the pChE level started to increase when they were 6 weeks old and reached a level of 5.7 μkat/1 ± 0.6 before slaughter at 6 months of age. The heifers did not show this increase. They had a level of around 2 μkat/1 throughout the investigation. The eAChE level at birth was 119 μkat/1 and increased slowly to a level of 145 μkat/1 at 6 months. No differences between the sexes were found.The cows suffering from parturient paresis had a pChE level of 1.80 μkat/1 ± 0.30 before treatment with calcium (Ca). The level decreased significantly (P ≦ 0.001) after Ca-infusion to a level of 1.67 ukat/1 ±0.29. Group IV had a pChE level of 1.65 μkat/1 ± 0.42 at parturition. Two to 4 months later the cows that had recovered from milk fever had a level of 1.61 μkat/1 ± 0.31 and the control cows 1.66 ukat/1 ± 0.48. No differences between the groups were found for the eAChE level.The findings show that parturition influences the pChE level in cows and that sex influences the pChE level in calves between 6 weeks to at least 6 months of age. Furthermore the elevated pChE level found in the cows suffering from parturient paresis before Ca infusion may be a further sign of a disturbance in the cholinergic system with a special preference to the neuromuscular junctions.     

散放牧场泌乳初期低酸度酒精阳性乳患牛乳及血液学指标分析

以分娩4周内的137头荷斯坦牛为试验动物,筛选19头酒精检测阳性且CMT检测阴性的牛只作为试验组,14头酒精检测和CMT检测均呈阴性的牛只为对照组,进行乳汁理化指标、血细胞、血液生化指标的检测。结果表明,低酸度酒精阳性乳在泌乳初期的发病率为42.34%,多发于泌乳天数低的奶牛,与隐性乳房炎无相关性,可引起乳脂率升高、乳糖率降低;试验组奶牛血液血红蛋白、白细胞、淋巴细胞、中间细胞升高,中性粒细胞降低,血清总蛋白、球蛋白、钙、镁、葡萄糖和胆固醇降低,血清钠、β-羟丁酸升高。     

生鲜牛奶理化性状及其与酒精试验、酸度的关系

在对生鲜奶的评定系统中，通常以煮沸法来表示热稳定性或新鲜度，以酸度来衡量新鲜度。而又有许多地方．以酒精试验来替代煮沸法或酸度的测定。可行否?莫衷一是。本试验拟对此作一实样调查与评价。     

影响奶牛乳成分因素的研究进展

近年来我国奶牛养殖行业发展迅速,人们在专注于提高奶牛产奶量的同时,开始关注如何提高乳品质。奶牛自身的遗传与非遗传因素以及奶牛生活环境显著影响着乳成分,伴随奶牛品种和所处环境的变化,其乳成分与品质也会发生改变。在生产中植物提取物以其无毒、无害、无副作用等多种优势成为改善乳品质的天然添加剂,可以提高奶牛的泌乳性能、改善乳成分,具有使用价值和应用前景。本文通过综述奶牛品种、环境及天然植物提取物等多种饲料添加剂对乳成分的影响,以期为在生产实践中提高乳品质等提供理论依据。     

复合植物提取物对奶牛产奶量、乳成分和血液指标的影响

本试验旨在研究日粮中添加复合植物提取物对奶牛产奶量、乳成分和血液生理生化指标的影响。选择25～27月龄、1胎、泌乳天数(67±1) d、产奶量(32±5) kg/d且健康的泌乳高峰期荷斯坦奶牛40头,随机分为对照组和试验组,每组20个重复,每个重复1头牛。对照组饲喂基础日粮,试验组饲喂基础日粮+1g/(d·头)复合植物提取物(每克含辣椒油树脂3.5%、肉桂醛5.5%、丁香酚9.5%)。试验预试期3d,正试期60 d。结果表明:与对照组相比,试验组奶牛产奶量提高2.37%(P>0.05);日粮添加复合植物提取物有降低牛奶体细胞数、尿素氮含量的趋势(P>0.05);与对照组相比,试验组奶牛血常规指标、血清生理生化指标差异均不显著(P>0.05)。在本试验条件下,日粮添加1 g/(d·头)复合植物提取物能够在一定程度上提高奶牛产奶量、降低牛奶体细胞数和尿素氮含量,但不影响血液生理状态。     

酶制剂对泌乳前期奶牛产奶量和乳成分的影响

选择年龄、胎次、产奶量和泌乳时间相近的30头泌乳前期荷斯坦牛,随机分为3组(试验Ⅰ组、Ⅱ组和对照组),每组10头。在试验组精料补充料中添加300g/t和600g/t的非淀粉多糖酶制剂,研究其对奶牛产奶量和乳成分的影响。结果表明,与对照组相比,试验Ⅰ、Ⅱ组奶牛产奶量分别提高了1.18kg/d和1.23kg/d,乳脂率分别提高了0.03和0.39个百分点,乳蛋白率分别提高了0.01和0.05个百分点,体细胞数分别下降15.86万个/mL和14.63万个/mL,但差异均不显著(P>0.05);在泌乳前期的奶牛日粮中添加外源非淀粉多糖酶制剂具有促进奶牛泌乳、改善乳成分的趋势。