Prevention of Milk Fever by Dietary Means: The Effect of a Concentrate Fortified with Mineral Salts

A concentrate was fortified with mineral salts by adding CaCl₂, Al₂(SO₄)₃ and MgSO₄ to standard concentrate A and pelleting the product When used as feed supplement from 3 weeks pre partum to 1 week post partum this concentrate mixture produced the intended negative alkali alkalinity in the total feed ration in 20 out of 25 cows. Of these 17 remained healthy in spite of a history of milk fever for the majority of them. Two cows got milk fever and 1 showed weak symptoms.     

奶牛产乳热的发生及阴离子盐的应用

本文就影响产乳热的发生因素、防治措施及阴离子盐在预防奶牛产乳热中的应用作一介绍。     

日粮类型对奶牛粪尿特性及氮排放的影响

通过研究不同类型日粮对泌乳奶牛粪尿及氮排放的影响,达到减少和控制氮排放的目的,本试验选用12头体重514 kg、年龄3～5岁的中国荷斯坦奶牛为试验动物,分为3组,分别饲喂粗料为干秸秆玉米,精粗比40∶60的A日粮、粗料为玉米青贮,精粗比分别是40∶60和60∶40的B和C日粮进行了对其粪尿特性及氮排放的试验研究。结果表明,日粮类型对奶牛粪便及尿液产生量均有一定的影响。粪便产生量结果为秸秆型A日粮>青贮型低精比B日粮>青贮型高精比C日粮。3种日粮的尿液产生量为C日粮>B日粮>A日粮。同时,日粮类型对奶牛氮平衡具有显著的影响,秸秆型日粮的乳氮、尿氮含量和氮的消化率极显著低于青贮型日粮低(P<0.01),粗料均为青贮玉米条件下,随日粮精料水平的提高,氮消化率和尿氮极显著增加(P<0.01),粪氮和乳氮增加不显著(P>0.05)。结果提示,秸秆型日粮的摄入氮主要是从粪中排出,粗料为青贮玉米时,随日粮精料水平的提高粪氮比例减少,而尿氮比例增加,粪氮和尿氮占总粪尿氮的比例基本一致。     

胡萝卜对奶牛产奶量及乳成分的影响

试验通过在产奶牛日粮中添加胡萝卜,研究胡萝卜不同饲喂量对舍饲奶牛的奶产量和乳成分的影响。试验牛选用中国荷斯坦奶牛,体重500~600 kg,胎次为头胎、泌乳100 d左右的健康荷斯坦奶牛30头,采用完全随机区组设计,分为3个处理组,试验1组为对照组(基础日粮),试验2组(基础日粮+5 kg胡萝卜)、试验3组(基础日粮+7.5 kg胡萝卜)为试验组,基础日粮由全株青贮玉米、羊草和精料组成。研究结果显示,奶牛在添加胡萝卜后能够显著提高产奶量,90 d后试验2组的产奶量比对照组提高了11.94%(P<0.05),试验3组的产奶量比对照组提高了16.17%(P<0.05),牛奶的风味也得到很大的改善。     

过瘤胃氨基酸高能复合物对奶牛产奶量及乳成分的影响

为研究不同过瘤胃氨基酸高能复合物对奶牛产奶量及乳成分的影响,试验选择胎次(3～5胎)、产奶量、产犊日期相近,体重(600±20)kg健康荷斯坦泌乳高峰期奶牛24头,随机分为4组,每组6头。1组为对照组,饲喂牛场常规日粮;2、3、4组为试验组,分别在常规日粮基础上添加过瘤胃氨基酸高能复合物Ⅰ、Ⅱ、Ⅲ500 g/(d.头)。正式期60 d。结果表明:奶牛日粮中添加过瘤胃氨基酸高能复合物后,均可明显提高奶牛产奶量、乳脂率、乳蛋白率及乳中总干物质含量。尤其是复合物Ⅲ,添加效果最为理想,平均日产奶量、乳脂率、乳蛋白率及总干物质含量分别比对照组提高21.19%(P<0.05)、21.31%(P<0.05)、9.72%(P<0.05)和10.34%(P<0.05),平均日校正乳产量提高35.70%(P<0.05)。     

The effect of cobalt topdressing in preventing cobalt deficiency disease of lambs in southland

Environmental samples and samples of partially processed fish from a cold-smoked salmon processing and packing plant, and product samples purchased from retail outlets, were examined for the presence of Listeria monocytogenes and other Listeria spp., motile aeromonads and Yersinia enterocolitica. Listeria spp. were not isolated from rati fish but were a contaminant of processed and partially processed fish. Listeria spp. were also detected in 18.8% of surfaces in contact with fish. Unlike Listeria spp., motile aeromonads were isolated from the raw fish but not from the finished product. They were more frequently isolated from environmental sources than Listeria spp. Yersinia enterocolitica was not isolated from any of the samples tested. Little evidence was found to show a coincidence of motile aeromonads and Listeria spp., since only one subset of samples showed such a link. It is concluded that contamination by Listeria spp. was from environmental sources at the processing plant at, or beyond, the slicing stage. Reducing the number of wet areas and special cleaning and sanitation considerations for a contaminated site (the freezer seal) are suggested as ways of reducing contamination of the product.     

植物甾醇对泌乳前期奶牛产奶量及乳成分的影响

根据年龄、胎次、泌乳时间和产奶量选择24头泌乳奶牛,随机分为对照组、试验Ⅰ组和试验Ⅱ组。对照组饲喂奶牛场配制的全混合饲料,试验Ⅰ和Ⅱ组每头奶牛日粮中分别添加40 g/d和80 g/d植物甾醇,研究植物甾醇对奶牛生产性能的影响。结果表明,与对照组相比,试验Ⅰ和Ⅱ组奶牛的产奶量分别提高了2.07 kg/d(5.64%,P0.05)和1.74 kg/d(4.75%,P0.05);试验Ⅰ和Ⅱ组奶牛乳脂率分别提高了8.22%(P0.01)和2.97%(P0.05);乳蛋白率分别提高了2.45%(P0.05)和1.05%(P0.05);非脂固形物分别提高了1.29%(P0.05)和0.23%(P0.05),体细胞数分别下降了37.31%和19.34%,但差异均不显著(P0.05);牛奶中乳尿素氮含量分别降低了5.29%(P0.05)和7.58%(P0.01)。结果表明泌乳前期奶牛补饲一定量的植物甾醇能够提高产奶量和改善乳成分。     

Relationship between milk cortisol concentration and the behavioral characteristics of postpartum cows introduced to a new group

The objective of this study was to examine the relationship between milk cortisol concentration (MC) and behavioral responses to stress. As a stress response, the behaviors of 37 postpartum cows were observed when they were introduced into a new group. Milk samples for MC measurement and milk trait data were collected on the test day every 2 months after calving. The best linear unbiased prediction (BLUP) was estimated from each behavioral and milk trait data. Behavioral BLUP data were subjected to principal component (PC) analysis and three PCs were extracted. The first PC, with large loadings for eating and allogrooming, was positively correlated with milk yield. Therefore, individual differences in behaviors closely related with PC1 would have been unconsciously paid a lot of attention in terms of productivity. However, the second PC, with large loadings for drinking and self‐grooming, uncorrelated with any milk traits, had a negative correlation with MC. The third PC, with large loadings for exploring, fighting and the frequency of agonistic behavior, was uncorrelated with all traits. Both PC2 and PC3 were independent of productivity, and individual differences in behaviors related with these PCs may be scarcely considered.     

奶牛临床型乳房炎Nisin抗菌肽治疗后日产奶量及主要乳成分的变化

选取临床型乳房炎自然发病病例9头,乳房内灌注乳酸链球菌素(Nisin)进行治疗,通过检测日产奶量以及停药后2,7,14,21 d的主要乳成分指标,确定Nisin乳房灌注剂对临床型乳房炎病例泌乳性能的影响情况。结果显示,乳房内灌注Nisin后患病乳区乳腺组织得到一定程度的修复,日产奶量逐渐恢复,停药后8 d的日产奶量与发病前6 d相比,平均降幅2.5 kg。治愈后患病乳区牛奶乳脂肪、乳蛋白、乳糖和非脂乳固体含量都呈现上升趋势,但与同期相比,略低于非用药乳区混合牛奶;其中,乳糖含量增加幅度较快,除停药后2 d的治疗乳区外,乳糖含量均在4.7%以上,提示奶牛乳房炎病例经Nisin乳房灌注治疗后,受损乳腺组织修复较快,乳腺上皮细胞合成乳成分的能力大幅度提高。由此可见,Nisin对奶牛临床型乳房炎具有良好的治疗作用。     

Effects of a pantothenic acid supplementation to different rations on ruminal fermentation, nutrient flow at the duodenum, and on blood and milk variables of dairy cows

To investigate the effects of a dietary pantothenic acid (PA) supplementation on duodenal nutrient flows, blood and milk variables and especially on duodenal PA flows and PA concentrations in blood and milk German Holstein cows, equipped with cannulas in the dorsal sac of the rumen and in the proximal duodenum were used. In the first experiment of the study two dry and six lactating cows received a diet with a forage to concentrate (F:C) ratio of 34:66 (high concentrate, HC), whereas in the second experiment a diet with a F:C ratio of 66:34 (high forage, HF) was fed to four dry and five lactating cows. The cows received both rations with or without 1 g PA/day. By supplementing PA to the HC ration, the molar percentage of acetic acid increased, whereas the concentration of total short chain fatty acids, the efficiency of microbial protein synthesis in the rumen and the serum glucose levels, decreased. With the HF ration the PA decreased the molar percentage of propionic acid and increased the amount of ruminally fermented organic matter. Furthermore, PA supplementation only increased the duodenal PA flow with the HF ration, while the serum and milk PA concentrations and milk PA yields were not affected. Based on the results of the present study, a rumen-unprotected supplementation of PA makes no sense.     

甘油代替大麦对泌乳中后期奶牛采食量、产奶量和乳质量的影响

文章旨在确定在不影响牛奶产量、牛奶成分、乳脂肪酸组成和牛奶感官质量的情况下,用不同水平甘油代替大麦对泌乳中后期奶牛的影响。试验选择了40头荷斯坦奶牛,采用4×4拉丁方试验设计。在部分混合日粮中,粗甘油替代大麦的含量分别为日粮干物质的0、6%、12%和18%。每天记录个体产奶量、采食量和挤奶频率,每周分析牛奶成分。对新鲜牛奶和贮藏7 d的牛奶样品进行感官分析。部分混合日粮的摄入量随甘油添加水平由0升高至12%,增加近1 kg,甘油由12%升高至18%,减少约1 kg。甘油水平由0升高至6%时,精料摄入量下降0.5 kg。随着日粮中甘油比例的增加,牛奶产量呈线性下降(P<0.05),而牛奶中的脂肪和蛋白质含量呈上升趋势(P=0.08),导致能量校正乳水平随甘油水平的升高表现为二次曲线效应,其中6%甘油组产量最高,18%甘油组产量最低。蛋白质和乳糖产量随日粮中甘油比例的增加线性下降(P<0.05)。随着日粮甘油比例的增加,牛奶中棕榈酸、油酸、亚油酸、亚麻酸和共轭亚油酸的比例线性下降(P<0.05),而短链和中链脂肪酸的比例大部分呈上升趋势。综上所述,甘油作为一种能量饲料可以在不影响牛奶品质的前提下,在泌乳中后期奶牛日粮中替代大麦的水平高达18%。但日粮甘油水平超过12%时可能会降低能量校正乳的产量。     

奶牛酒精阳性乳与微量元素Zn、Cu、Mn、Fe含量及自由基代谢的关系

对酒精阳性乳患牛全乳、乳清、血清中Zn、Cu、Mn、Fe的含量进行了检测，同时检测了乳清与血清中的抗氧化指标。结果表明：阳性牛乳清与血清中超氧化物歧化酶（superoxide dismutase，SOD）、谷胱甘肽过氧化物酶（glu—tathione peroxidase，GSH—Px）活性均降低，丙二醛（malondialdehyde，MDA）含量升高；全乳、乳清、血清中zn含量均极显著降低，血清Mn、Fe含量略低，乳清Cu含量降低。综合分析，酒精阳性牛机体总抗氧化能力下降，不能有效清除氧化代谢产物，以至于过多的氧自由基对乳腺上皮细胞膜造成损伤，从而引起乳腺细胞分泌异常乳。     

微量元素添加剂对奶牛泌乳性能影响

针对奶牛日粮营养不平衡,导致产奶量低、乳脂率低,经济效益低的生产状况,本试验随机选择4胎、5胎、6胎泌乳期牛10头,分试验组与对照组,各试验牛按日产奶量饲喂不等量精料补充料、玉米秸与稻秸按2:1混合的粗饲料、尿素基础饲粮。试验组饲粮按产奶量分等添加微量元素添加剂,试验期试验组奶料比为3.25,对照组为2.9,试验组增加0.34kg(P<0.05)。试验期产奶量按4.0%标准乳计算,试验组日产奶量高于对照组4.31kg(P<0.05)。按每kg增重折合鲜奶8.0kg校正体重后标准乳计算,试验组日产奶量高于对组4.36kg(P<0.01)。乳脂、乳钙、乳蛋白质(2.29 乳脂率×0.33计算),试验组比对照组分别提高0.32%、0.10%、0.03%(P<0.05)。添加微量元素的试验组,头均日产标准奶24.12kg,对照组19.8kg(P<0.05),按kg鲜奶1.80元计算,头、日产奶分别收入43.42元、35.62元(P<0.05)。头均日耗饲料的实际价格试验组9.15元、对照组7.82元(P<0.01),试验组比对组多增收6.46元(P<0.05),经济效益显著。     

Effect of feed restriction on dairy cow milk production: a review

In the dairy cow, negative energy balance affects milk yield and composition as well as animal health. Studying the effects of negative energy balance on dairy cow milk production is thus essential. Feed restriction (FR) experiments attempting to reproduce negative energy balance by reducing the quantity or quality of the diet were conducted in order to better describe the animal physiology changes. The study of FR is also of interest since with climate change issues, cows may be increasingly faced with periods of drought leading to a shortage of forages. The aim of this article is to review the effects of FR during lactation in dairy cows to obtain a better understanding of metabolism changes and how it affects mammary gland activity and milk production and composition. A total of 41 papers studying FR in lactating cows were used to investigate physiological changes induced by these protocols. FR protocols affect the entire animal metabolism as indicated by changes in blood metabolites such as a decrease in glucose concentration and an increase in non-esterified fatty acid or β-hydroxybutyrate concentrations; hormonal regulations such as a decrease in insulin and insulin-like growth factor I or an increase in growth hormone concentrations. These variations indicated a mobilization of body reserve in most studies. FR also affects mammary gland activity through changes in gene expression and could affect mammary cell turnover through cell apoptosis, cell proliferation, and exfoliation of mammary epithelial cells into milk. Because of modifications of the mammary gland and general metabolism, FR decreases milk production and can affect milk composition with decreased lactose and protein concentrations and increased fat concentration. These effects, however, can vary widely depending on the type of restriction, its duration and intensity, or the stage of lactation in which it takes place. Finally, to avoid yield loss and metabolic disorders, it is important to identify reliable biomarkers to monitor energy balance.     

饲喂霉菌毒素吸附剂对牛奶中黄曲霉毒素M1残留量的影响

根据年龄、胎次、泌乳阶段和产奶量相近的原则选择15头荷斯坦牛,随机分为对照组、试验1组、试验2组,分别在精料补充料中添加0、1000 g/t和2000 g/t霉菌毒素吸附剂。结果表明,添加霉菌毒素吸附剂对降低奶牛乳中黄曲霉毒素M1有一定的作用,并能够提高奶牛产奶量(P<0.05),对乳成分和其他相关指标无显著影响。     

Effect of monensin and vitamin E on milk production and composition of lactating dairy cows

Feeding unsaturated oils to lactating dairy cows impair ruminal biohydrogenation (BH) of unsaturated fatty acids (USFA) and increase ruminal outflow of BH intermediates such as trans‐10, cis‐12 CLA that are considered to be potent inhibitors of milk fat synthesis. Supplementing lactating dairy cow’s rations containing plant origin oils with monensin and/or vitamin E may minimise the formation of trans‐10 isomers in the rumen, thereby preventing milk fat depression. Therefore, this study was conducted to evaluate the effects of monensin and vitamin E supplementation in the diets of lactating dairy cows containing whole cottonseed, as the main source of FA on feed intake, milk production and composition, milk fatty acid profile, efficiency of nitrogen (N) utilisation, efficiency of net energy (NE) utilisation and nutrients digestibilities. Four multiparous Holstein lactating dairy cows (86 ± 41 days in milk) were assigned to a balanced 4 × 4 Latin square design. Each experimental period lasted 21 days with a 14 days of treatment adaptation and a 7 days of data collection. The control diet was a total mixed ration (TMR) consisted of 430 g/kg forage and 570 g/kg of a concentrate mixture on dry matter (DM) basis. Cows were randomly assigned to one of the four dietary treatments including control diet (C), control diet supplemented with 150 mg of vitamin E/kg of DM (E), control diet supplemented with 24 mg of monensin/kg of DM (M) and control diet supplemented with 150 mg of vitamin E and 24 mg of monensin/kg of DM (EM). Dry matter intake (DMI) ranged from 19.1 to 19.5 kg/d and was similar among the dietary treatments. Dietary supplementation with vitamin E or monensin had no effect on milk production, milk fat, protein and lactose concentrations, efficiency of utilisation of nitrogen and net energy for lactation (NE_L). Digestibility of DM, organic matter (OM), crude protein (CP) and ether extract (EE) was not affected by the dietary treatments. Digestibility of neutral detergent fibre (NDF) was higher in cows fed with the M and EM diets in relation to those fed the C and E diets. The concentrations of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C15:0, trans‐10‐16:1, cis‐9‐16:1, 17:0, 18:0, trans‐11‐18:1, cis‐9‐18:1, cis‐9, trans‐11 conjugated linoleic acid (CLA), trans‐10, cis‐12 CLA, and 18:3n‐3 FA in milk fat were not affected by the dietary supplementations. While feeding the M diet tended to decrease milk fat concentration of C16:0, the milk fat concentration of C18:2n‐6 FA tended to be increased. Dietary supplementation with vitamin E or monensin had no effect on milk fat concentrations of saturated, unsaturated, monounsaturated, polyunsaturated, short chain and long chain FA, but feeding the M diet numerically decreased milk fat concentration of medium chain fatty acids (MCFA). The results showed that vitamin E and/or monensin supplementations did not improve milk fat content and did not minimise the formation of trans‐10 FA isomers in the rumen when whole cottonseed was included in the diet as the main source of fatty acids.     

Characterization of the serum metabolic profile of dairy cows with milk fever using 1H-NMR spectroscopy

Background: Milk fever (MF) is a common calcium metabolism disorder in perinatal cows. Currently, information regarding the detailed metabolism in cows suffering from MF is scant.

Objective: The purpose was to study the metabolic profiling of serum samples from cows with MF in comparison to control cows, and thereby exploring other underlying pathological mechanisms of this disease.

Animals and methods: In the current study, we compared the serum metabolomic profile of dairy cows with MF (n = 8) to that of healthy dairy cows (n = 24) using a 500-MHz digital ¹H-nuclear magnetic resonance (¹H-NMR) spectrometer. Based on their clinical presentation and serum calcium concentration, cows were assigned either to the control group (no MF symptoms and serum calcium concentration >2.5 mmol/L) or to the MF group (MF symptoms and serum calcium concentration <1.4 mmol/L). For statistical analysis, a one-way analysis of variance was performed.

Results: We identified differences regarding nine metabolites between the two groups, among which glucose, alanine, glycerol, phosphocreatine, and gamma-aminobutyrate decreased, and β-hydroxybutyrate, acetone, pyruvate, and lysine increased in cows with MF. Most of these were carbohydrates and amino acids involved in various energy metabolism pathways.

Conclusion: The different metabolites in cows with MF reflected the pathological features of negative energy balance and fat mobilization, suggesting that MF is associated with altered energy metabolism.

Clinical importance: The ¹H-NMR spectroscopy can be used to understand the pathogenesis of MF and identify biomarkers of the disease.     

Concentrations of retinol and tocopherols in the milk of cows supplemented with conjugated linoleic acid

This study was performed to investigate the hypothesis that supplementation of conjugated linoleic acid (CLA) changes the concentrations of retinol and tocopherols in the milk of cows. To investigate this hypothesis, Holstein cows received daily from 3 weeks ante‐partum to 14 weeks post‐partum either 172 g of a CLA‐free rumen‐protected control fat (control group, n = 20) or the same amount of a rumen‐protected CLA fat, supplying 4.3 g of cis‐9, trans‐11 CLA and 3.8 g of trans‐10, cis‐12 CLA per d (CLA group, n = 20). Milk samples (collected at weeks 1, 3, 5, 8 and 11 of lactation) were analysed for retinol, α‐ and γ‐tocopherol concentrations. Milk of cows supplemented with CLA had higher concentrations of retinol (+34%), α‐tocopherol (+44%) and γ‐tocopherol (+21%) than milk of control cows (p < 0.05). The daily output of these vitamins via milk was also greater in cows of the CLA group than in cows of the control group (+36, 50 and 24% for retinol, α‐tocopherol and γ‐tocopherol, respectively, p < 0.05). In agreement with higher concentrations of tocopherols, concentrations of thiobarbituric acid‐reactive substances, determined in milk of week 5, were lower in cows of the CLA group than in control cows, indicative of a lower susceptibility of milk lipids to peroxidation. Plasma concentrations of retinol and α‐tocopherol, determined at 1 and 5 weeks post‐partum, were not different between the two groups of cows. In conclusion, this study shows that supplementing dairy cows with a moderate amount of CLA causes an increase of the concentrations of vitamins A and E in the milk and results in an increased output of those vitamins via milk. These effects might be beneficial with respect to the nutritional value of dairy products and the susceptibility of milk fat to oxidative deterioration.     

Effect of brewer's grain on rumen fermentation, milk production and milk composition in lactating dairy cows

Six lactating Holstein cows were divided into two groups (n = 3) and used in a double reversal trial with three periods of 14 days each to evaluate the rumen fermentation, milk production and milk composition of cows fed brewer's grain (BG). The control diets contained 14% chopped Sudangrass hay, 24% corn silage, 18% alfalfa hay cube, 34% concentrate mixture‐1 and 10% concentrate mixture‐2 (wheat bran, soybean meal and cottonseed). In the experimental diet, wet BG replaced the concentrate mixture‐2. The protozoal population, concentration of ammonia‐N and volatile fatty acids in the ruminal fluid did not differ between the control and BG diets. The molar percentage of acetic acid was significantly higher (P < 0.05) with the BG diet at 5 h after feeding. The milk yield, the percentage of protein, lactose, solids not‐fat and somatic cell counts of milk did not differ between the two diets. The percentage of milk fat tended to increase with the BG diet. The BG diet significantly increased the proportions of C18:0 and C18:1 in milk fat (P < 0.01, P < 0.05, respectively) and tended to increase that of conjugated linoleic acid.