Study on the Effects of Chinese Herb Additive on Milk Yield and Anti-heat Stress Ability of Holstein Cow

[Objective] The research aimed to explore the effects of Chinese herb additive on milk yield and anti-heat stress ability of Holstein cow.[Method] 36 Holstein cows with similar birth order and milk yield were equally and randomly divided into 3 groups which were control group, Chinese medicine Ⅰ group and Chinese medicine Ⅱ group. In control group, cows were fed with basic feed, while in Chinese medicine Ⅰ group, cows were fed with basic feed containing 4% compound Chinese herb additive and in Chinese medicine Ⅱ group, cows were fed with basic feed containing 3% compound Chinese herb additive.All cows in the 3 groups were analyzed comparatively.[Result] Adding some compound Chinese herb additive into basic feed would increase milk yield and anti-heat stress ability of Holstein cow,besides,it also could decrease cow diseases such as cow mastitis.Chinese medicine Ⅰ would generate the highest economic benefit of practical production.[Conclusion] Adding Chinese herb additive into basic feed is an effective way for reliefing heat stress and increasing milk yield.

Milk Yield and Composition and Pasture Ruminal Digestion in Grazing Dairy Cows Receiving Three Levels of Energy Concentrate Supplementation

The objective of the experiment was to determine the effect of feeding three levels (T3.5, T7.0 and T10.5) of energy concentrate (3.5, 7.0 and 10.5 kg cow-1 day-1) on total dry matter (DM) and energy intakes, milk yield and composition, nutritional value of milk and rumen pasture neutral detergent fiber (NDF) digestion in grazing dairy cows. Twenty-one multiparous Holstein cows in early lactation (70.2 ± 13 days postpartum) producing 37.1 (±4.7) kg of milk were assigned to a 3 treatments (7 cows/treatment) × 3 periods Latin square design. Parameters of ruminal environment and pasture NDF degradation were obtained using 3 additional cows of the same breed fitted with rumen cannulae. On a wet basis, concentrate was composed by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral nucleus with monensin. Pasture (Medicago sativa, sp) was used in a rotational grazing system with an herbage allowance of 30 kg DM cow-1 d-1. Yield (kg cow-1 d-1) of fat corrected milk (4% FCM) resulted higher (p < 0.05) in T7.0 (29.0) compared to T3.5 (26.8) but similar to T10.5 (30.2). Milk and protein yields were linearly increased (p < 0.01) by concentrate intake. Milk fat (3.13 g/100g) and total solid contents (11.79 g/100g) did not differ whereas milk protein (p < 0.03) and casein (p < 0.01) levels (g/100g) increased linearly from 3.05 to 3.10 (protein) and from 2.42 to 2.47 (casein). Pasture intake decreased but total DM and energy consumption were enhanced showing addition effects after concentrate feeding. Body weight (BW) loss and plasmatic levels of non esterified fatty acids (NEFA) decreased with concentrate intake. Circulating levels of insulin-like growth factor-I (IGF-I) were higher (p < 0.05) in T10.5 while those of glucose, plasma urea nitrogen, insulin and somatotrophin were not affected. Ruminal pH and acetate concentration resulted lower (p < 0.05) in T10.5 when compared to T3.5. The acetate:propionate ratio decreased (p < 0.01) from 4.25 in T3.5 to 3.08 in T10.5 and ruminal ammonia nitrogen levels tended (p < 0.07) to be lower as concentrate intake increased. Kinetics parameters of NDF degradation remained unchanged. The potential hypercholesterolemic fatty acids (FA) of milk (C12:0 to C16:0.) remained unchanged as concentrate intake increased. Milk content of linolenic acid decreased and the n-6:n-3 ratio increased with concentrate intake from 1.56 (T3.5) to 2.57 (T10.5) remaining below the recommended values for human health (<4:1). Milk content of antioxidant vitamins was not significantly altered even when pasture DM intake fall in T10.5 compared to T3.5. Increased consumption of a starch-rich concentrate up to 40% of DM intake of cows showed additive effects on total DM and energy intakes improving milk yield, milk protein and casein contents without negative effects on milk fat concentration or yield. Pasture fiber digestion and nutritional parameters linked to healthy value of milk fat were not affected.

An Essential Oil Blend Decreases Methane Emissions and Increases Milk Yield in Dairy Cows

This study was conducted to investigate the effect of a commercial essential oil (EO) additive on milk production and methane (CH4) emissions from dairy cows. Early lactation Holstein-Friesian dairy cows were fed grass, whole crop wheat and corn silage total mixed ration. Cows were allocated to one of two experimental treatments: Control (no additive, CON) or 1 g/head/day of EO. Cows were housed in a free stall barn, split into two pens for the duration of the experiment. Two gas data loggers units used to measure CH4 emissions were provided per pen for the duration of the 22 week-long study. Milk yield was determined daily, and milk components were analyzed every two weeks. CH4 was recorded continuously, and daily values were tabulated. Body weight and body condition score were determined at the start and bi-weekly. Results were analyzed as a randomized complete block trial. In total, 149 cows participated in the study (76 CON, 73 EO). Milk yields were greater (P < 0.05) for the test treatment (28.3 CON, 31.2 EO) with no change in milk component concentrations. Milk component concentrations were unaffected (P > 0.05) by treatment. Yields of fat, protein, lactose, and solids were higher for EO fed cows (P 4 output was reduced with the EO compared to the CON treatment (411 g/day vs 438 g/day;13.8 g/L of milk vs 17.2 g/L of milk, P < 0.05) over the duration of the trial. There were no effects of treatment on reproductive performance or the occurrence of mastitis. Feeding EO to dairy cows reduced CH4 emissions whilst also increasing performance.

Milk Yield of Holstein Cows Induced into Lactation Twice Consecutively and Lactation Curve Models Fitted to Artificial Lactations

Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate （2 mg kg-1 of body weight （BW） d-1, on day 1 to 14）, progesterone （0.10 mg kg-1 of BW, on day 1 to 7）, lfumethasone （0.03 mg kg-1 of BW, on day 18 to 20） and recombinant bovine somatotropin （rbST;500 mg per cow, on day 1, 6, 16 and 21）. At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artiifcially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk （DIM） did not differ between the ifrst and second induced lactations （（9 710 ＆#177;1 728） vs. （9 309＆#177;2 150） kg;mean＆#177;SD）. Total milk yield （（12 707＆#177;3 406） vs. （12 306＆#177;4 218） kg;mean＆#177;SD） and lactation length （（405＆#177;100） vs. （410＆#177;91） d;mean＆#177;SD） were not different between the ifrst and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon （n=334）, 18-mon （n=164） and 29-mon （n=22） lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl （Y=ab1/xxc）, Wood （Y=axb exp（cx）） and Dhanoa （Y=ax（bc）exp（cx）） models were equally suitable to describe 12-mon lactations. An exponential model with ifve parameters （Y=exp（a＋bx＋cd2＋e/x）） showed the best ift for milk yield for 18-mon lactations. The rational model （Y=a＋bx/1＋cx＋dx2） was found to produce the closest ift for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the ifrst cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artiifcial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for iftting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation.

Effects of Chinese Herb Additive on Milk Yield and Anti-heat Stress Ability of Holstein Cows

[Objective] To explore the effects of Chinese herb additive on milk yield and anti-heat stress ability of Holstein diary cow. [Method] A total of 36 Holstein cows at same parity and with similar milk yield were randomly divided into three groups, namely, control group, Chinese medi- cine group I and Chinese medicine group I1. The cows in the Chinese medicine group I were fed basal diet containing 4% compound Chinese herb additive; those in the Chinese medicine group II were fed basal diet containing 3% compound Chinese herb additive; and those in the control group were fed common basal diet. All cows in the three groups were analyzed comparatively. [Result] Supplementing some compound Chinese herb ad- ditive into basal diet increased milk yield and anti-heat stress ability of Holstein cows, besides, it also decreased cow diseases like cow mastitis. The Chinese medicine group I generated the highest economic benefit of practical production. [ Conclusion] Supplementing Chinese herb additive in- to basal diet is an effective way to relieve heat stress and increase milk yield.

Use of Random Regression Test-Day Model to Estimate Genetic Parameters of Milk Yield in Holstein Cows

(Co) variance components and genetic parameters were estimated for milk yield of Iranian Holstein cows. A total number of 68,945 milk test-day records of first, second and third lactations of 8515 animals from 100 sires and 7743 dams originated from 34 herds collected during 2007 to 2009 by Iranian animal breeding center were used. The ASReml computer program was used to analyze the milk test-day records using the random regression procedure. Herd test date (HTD), milking times per day (milking frequency), number of lactations, year of birth, year of calving, age of animal at calving and days in milk (DIM) considered as fixed effects and additive genetic effects and animal permanent environmental effects were considered as the random effects. Additive genetic variance, animal permanent environment variance, residual variance, phenotypic variance, heritability and repeatability were estimated during different months of lactation between 5.7 - 19.6, 15.3 - 27.1, 31.4 - 17.2, 45.8 - 64.83, 0.1 - 0.32 and 0.4 - 0.6, respectively. Genetic correlation and phenotypic correlation were also estimated between months of lactation in range of -0.35 - 0.98 and 0.03 - 0.67, respectively. Genetic correlation and phenotypic correlation both showed the same changing pattern and they decreased as the interval between months of lactation increased.

A Study on the Correlation of Milk Yield of Cows with Seismicity and ULF Magnetic Field Variations

A statistical study on the basis of one-year data of 2014 has been performed in order to find whether abnormal animal behavior is related with seismic activity and also whether the ULF (Ultra Low Frequency) electromagnetic radiation might be a possible sensory mechanism of abnormal animal behavior. Abnormal animal behavior has been studied with the use of digitally recorded milk yield of cows at Ibaraki Prefecture Livestock Station, and the ULF magnetic field changes have been studied with the data at a magnetic observatory of Kakioka. As the result of correlation analyses, clear responses are observed for both the milk yield of cows and ULF magnetic field changes (both ULF radiation (ULF emissions from the lithosphere) and ULF depression (as an indicator of lower ionospheric perturbations)) for most powerful and not distant earthquakes (EQs) with magnitude > 6, that is, the milk yield of cows is found to exhibit a conspicuous depletion about 17 - 18 days before an EQ, though the correlation coefficient is not so big. Another important objective in this paper is to identify that ULF radiation is the main agent of abnormal behavior so that we have compared the temporal evolutions of milk yield of cows, ULF radiation and ULF depression for three major EQs. As a result, it is found that ULF radiation happens, at least, during the periods of abnormal depletion of milk yield of cows.

Effect of Bospro on High and Mid-to-Low Milk Yielding Chinese-Holstein Cow

A total of 90 cows from two farms (farm A 30 cows, farm B 60 cows) were used to study the effect of Bospro on milk production, milk quality and subclinical mastitis incidence. The cows in the test group were supplied with 20 g of Bospro per head per day and meanwhile, the percentage of milk fat, protein and lactose and moisture of the milk samples were analysed. The results showed that the milk yield of both high production and mid-to-low milk producting cows increased by 3.3% to 5.3% respectively compared with their control group of cows, but there was no changes on the milk content between the treated and the control cows. The treated cows also showed an increased body weight (P>0.05) and significantly reduced incidence of mastitis, as Compared with that of the control group.The experiment dcmonstrats that Bospro can increase milk yield, but not at the expense of milk quality and body weight.

Bacillus subtilis Co-transfected with a Lysine-rich and a Methionine-rich Protein Gene and Its Effect on Cow Milk Production

The probiotic Bacillus subtilis （B. subtilis） was widely applied in animal production as feed additive. Lysine （Lys） and methionine （Met） were the two most important limiting amino acids in livestock animal feed. Raising Lys and Met contents in B. subtilis would provide better effects for animal production and save Lys and Met supplements. We still didn＇t know whether Lys- rich and Met-rich protein genes from plants could be transfected into B. subtilis and expressed at a high level so as to improve animal production, such as milk production as an additional diet. The Lys-rich protein gene （Cflr） and Met-rich 10 ku-δ Zein were cloned from pepper anther and maize endosperm, respectively. Then they were constructed into plasmids individually and successfully cotransfected into B. subtilis. Upon IPTG induction, mRNAs and protein expressions could be observed. Lys and Met contents in the fermentation broth were raised by 65.92% and 46.39%, respectively. After feeding 200 g and 400 g· cow^-1· d^-1, transgenic B. subtilis fermentation broth, the milk yield, milk protein and milk fat contents all significantly increased. The Lys-rich protein gene （Cflr） and Met-rich 10 ku-δ Zein were successfully transfected into B. subtilis. Contents of Lys and Met in the transgenic B. subalis obviously raised and the fermentation broth of the transgenic bacteria could effectively improve milk yield and quality.

基于DHI数据分析不同因素对规模化牛场奶牛泌乳性能的影响

为进一步明确奶牛生产性能测定(DHI)在规模化奶牛场养殖管理中的作用,对陕西关中地区A、B、C 3个奶牛场2020年12月至2021年11月的DHI数据进行整理统计,分析季节、胎次、泌乳天数以及体细胞数(SCC)等不同因素对奶牛日产奶量和乳成分的影响。统计分析数据表明,冬季的乳脂率与乳蛋白率显著高于春季和夏季;第2~5胎次时奶牛有较高的日产奶量、高峰奶量和305 d奶量;泌乳天数在50~100 d时奶牛的日产奶量最大,泌乳天数大于100 d后,日产奶量逐渐下降;当SCC增加时,奶牛日产奶量、持续力以及305 d奶量逐渐降低,乳脂率和乳蛋白率逐渐升高。相关性分析数据表明,不同季节日产奶量与乳脂率、乳蛋白率均呈显著正相关;不同胎次奶牛日产奶量与乳脂率、乳蛋白率、SCC及尿素氮相关性显著;泌乳天数在50~100 d时,日产奶量与乳脂率、尿素氮呈显著正相关,与乳蛋白率、SCC呈显著负相关,在100~150 d时,日产奶量与乳脂率、乳蛋白率呈显著负相关,与SCC、尿素氮呈显著正相关;不同SCC条件下,奶牛日产奶量与乳脂率、尿素氮含量均显著正相关,当SCC小于25万个/mL时,奶牛日产奶量与乳蛋白率呈显著正相关,当SCC大于25万个/mL时,奶牛日产奶量与乳蛋白率呈显著负相关。结果表明,在陕西关中地区规模化奶牛场饲养管理过程中,应综合考虑季节、胎次、泌乳天数及SCC等因素的影响,因时因地优化饲养管理方案,从而提高奶牛泌乳性能和牛乳品质。

内蒙古不同地区奶牛产奶量及乳品质比较研究

[目的]对内蒙古不同地区生鲜牛乳进行质量等级划分,并对农区与牧区、规模化牧场与散养户奶牛的单产以及乳品质进行比较。[方法]于2023年10月分别从呼和浩特市规模化奶牛养殖场、呼和浩特市散养户奶牛场、呼伦贝尔市奶牛养殖场、锡林郭勒盟奶牛养殖场采集生鲜乳样品各30批次,共120批次,并收集各奶牛场生产记录信息。测定不同地区乳样的乳成分(乳脂率、乳蛋白率、总固体含量、非脂乳固体含量、乳糖含量)、体细胞数及菌落总数;依据《生牛乳质量分级》(NY/T 4054—2021)对3个地区的生鲜乳进行质量等级划分;采用统计学方法比较农区(呼和浩特市)与牧区(呼伦贝尔市及锡林郭勒盟)、呼和浩特市规模化牧场与散养户奶牛的平均单产以及生鲜乳品质。[结果]锡林郭勒盟牛场生鲜乳的乳脂率和菌落总数(6.16%,83.10×10^(4)CFU/mL)显著(P<0.05)高于呼和浩特市(3.96%,14.05×10^(4)CFU/mL)和呼伦贝尔市(4.15%,38.94×10^(4)CFU/mL);呼伦贝尔市牛场的生鲜乳体细胞数(39.99万个/mL)显著(P<0.05)高于锡林郭勒盟(18.18万个/mL)和呼和浩特市(18.35万个/mL);根据生牛乳质量分级标准,呼和浩特市牛场的生鲜乳为特优级,呼伦贝尔市和锡林郭勒盟牛场的生鲜乳为优级。农区牛场奶牛的平均单产和生鲜乳乳糖含量(29.07 kg/d,5.14%)显著(P<0.05)高于牧区(16.56 kg/d,4.85%);牧区牛场生鲜乳的乳脂率、体细胞数和菌落总数(4.88%,48.39万个/mL,49.52×10^(4)CFU/mL)显著(P<0.05)高于农区牛场(4.05%,20.20万个/mL,13.99×10^(4)CFU/mL)。呼和浩特市规模化牛场奶牛的平均单产以及生鲜乳非脂乳固体和乳糖含量(34.46 kg/d,9.44%,5.19%)显著(P<0.05)高于散养户(20.71 kg/d,9.21%,5.07%);散养户的生鲜乳体细胞数(23.24万个/mL)显著(P<0.05)高于规模化牛场(16.04万个/mL)。[结论]呼和浩特市生鲜乳质量优于呼伦贝尔市和锡林郭勒盟,农区牛场奶牛的产奶量及生鲜乳品质优于牧区,规模化牧场奶牛的产奶量及生鲜乳品质优于散养户。

解淀粉芽孢杆菌对奶牛泌乳性能、血清生化以及免疫功能的影响

[目的]研究解淀粉芽孢杆菌对泌乳牛产奶量、乳成分、血清生化和免疫功能的影响。[方法]选取体况健康、泌乳量(35.15±2.10) kg/d、胎次2.5±0.2及泌乳天数(102±5) d中国荷斯坦牛36头,采用单因素随机设计分为3组,每组4个重复,每个重复3头奶牛。对照组饲喂不添加解淀粉芽孢杆菌的基础日粮,2个试验组设计为分别饲喂基础日粮+150 mg/kg(150 mg/kg组)、基础日粮+200 mg/kg(200 mg/kg组)解淀粉芽孢杆菌粉剂日粮,每天1次。预试期3 d,正试期56 d。[结果]150 mg/kg组、200 mg/kg组乳蛋白率显著升高(P<0.05)。与对照组比较,150 mg/kg组总蛋白、尿酸、谷丙转氨酶均显著升高(P<0.05),200 mg/kg组尿素氮显著降低(P<0.05);150 mg/kg组、200 mg/kg组IgA、IgM含量均提高,其中150 mg/kg组IgA、IgM分别显著提高50.69%(P<0.05)、33.64%(P<0.05),150 mg/kg组显著提高γ-干扰素(P<0.05),200 mg/kg组显著降低肿瘤坏死因子-α(P<0.05)。[结论]日粮添加适当水平的解淀粉芽孢杆菌能提高奶牛产奶量和乳品质,增强免疫功能。

不同剂量过瘤胃氯化胆碱对围产期奶牛生产性能及血液生化指标的影响研究

[目的]为了探索不同剂量过瘤胃氯化胆碱对围产期奶牛产奶量、奶品质和血液生化指标的影响,以及作用机制。[方法]采用40头荷斯坦牛为试验对象,随机分为对照组、试验A组、试验B组和试验C组,其中对照组饲喂正常日粮,试验A组、B组和C组分别在日粮基础上添加10 g/头·d,20 g/头·d和30 g/头·d的过瘤胃氯化胆碱,检测其产奶量、奶品质、血糖、总胆固醇、甘油三酯和β-羟基丁酸变化。[结果]过瘤胃氯化胆碱能有效提高产奶量,增加奶中乳脂肪和乳糖含量,促进血糖恢复,降低总胆固醇和β-羟基丁酸,改善奶牛生产性能。[结论]日粮添加20 g/头·d过瘤胃氯化胆碱,改善奶牛生产性能、血液生化指标。

不同水平蔗糖对泌乳奶牛体外产气及泌乳的影响

[目的]研究不同蔗糖添加水平对泌乳奶牛体外产气、泌乳量、乳汁成分的影响。[方法]于内蒙古自治区赤峰市巴林左旗某规模化奶牛场随机选择90头(2~3)胎次、体重和年龄相近泌乳奶牛为研究对象,随机分为3组,分别为对照组、试验I组和试验II组,每组30头。对照组饲喂常规全混合日粮,试验I组和试验II组在饲喂常规全混合日粮基础上,添加2%、4%水平蔗糖,试验周期65 d。比较试验结束后奶牛体外产气量、泌乳量、乳汁成分。[结果]试验II组发酵48 h产气量、理论最大产气量、达到最大产气量1/2时的产气速率,高于试验I组和对照组(P<0.05),且试验I组高于对照组(P<0.05)。试验I组和试验II组产奶量略高于对照组,但比较无差异(P>0.05)。对照组、试验I组和试验II组脂蛋比、乳蛋白率、乳脂率、尿素氮、体细胞数等乳汁成分含量比较无显著差异(P>0.05)。[结论]泌乳奶牛常规全混合日粮中添加蔗糖,可在不影响瘤胃发酵模式基础上,加快体外产气速率,不影响产奶量、乳汁成分。4%蔗糖添加量效果最佳。

Effect of Feeding a Combination of Zinc, Manganese and Copper Methionine Chelates of Early Lactation High Producing Dairy Cow

The objective of the study was to compare the effect of feeding mixed chelated minerals (Mn, Cu and Zn) methionine on dairy cow productive performance and milk yield and its components. The trial was conducted with dairy cows across various stage of lactation. The experimental treatments include chelated minerals (15 mg Zn as Zn Met, 20 mg Mn as Mn Met, 10 mg Cu as Cu Met). Inorganic mixture contains (15 mg Zn as ZnSO4, 20 mg Mn as MnSO4, 10 mg Cu as CuSO4) in sulphate forms. The experiment was commenced in the dry period of cows, 6 weeks before calving, and after calving the first three months of lactation was taken into consideration. Milk samples were collected from each cow evening and morning for estimation of milk yield production. The inorganic metals caused a significant decline (P < 0.05) in digestibility coefficients, nutritive value, nitrogen utilization, Cell wall constituents, total VFA’s, rumen volume, microbial and nitrogen synthesis compared to the organic metals. The treated group (chelated minerals) improved the milk yield, and the milk fat percentage of animals across various stages of lactation as compared to inorganic minerals treated group of animals, and no significant differences were observed among groups concerning the entire blood constituent.

Effects of Supplementation with Increasing Levels of Energy Concentrate on the Productive Response and Ruminal Digestion of Dairy Cows Grazing Lucerne Pasture

The aim of the study was to determine the effect of three levels of energy concentrate intake on dry matter (DM) and energy intake, milk yield and composition, rumen environment and pasture neutral detergent fiber (NDF) digestion. Twelve Holstein multiparous cows in early lactation (69.0 ± 5 days postpartum) producing 32.8 (±4.0) kg milk were assigned to three treatments at (kg/cow day) 3.5 (T3.5), 7.0 (T7.0) and 10.5 (T10.5) kg concentrate in a 3 × 3 Latin Square design. Parameters of ruminal environment and neutral detergent fiber (NDF) digestion were obtained using 3 additional rumen cannulated cows. Concentrate was composed (as fed) by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral premix including monensin and thoroughly consumed. Yields (kg/cow day-1) of milk, 4% fat corrected milk (4% FCM 4%) and energy corrected milk (ECM) resulted higher (p p -1 without effects on yield of milk fat. Concentrations (g/100 g) of milk fat (3.19), protein (2.97), total solids (11.75), non-fat solids (8.60) and casein (2.40) did not differ. Milk lactose content (g/100 g) was linearly increased (p p p p p < 0.05) in T3.5 due to the increase in acetate and butyrate while the acetate: Propionate ratio remained unchanged. Pasture NDF digestion was affected as concentrate intake increased. To increase milk protein yield and reduce concentrations of N-NH3 in rumen and milk, feeding an energy concentrate at 41% of total DM intake resulted an effective tool.

Effect of Cysteamine-preparation on Dairy Performance of Dairy Holstein Friesian Cows

Thirty Holstein Friesian cows with similar weight, age, calving number, lactating length, fat percentage, and same physiology condition were selected and randomly divided into 3 groups: group I, group II and group III, 20 g and 40 g Cysteamine /(cow·day) was supplemented into the normal diet for group I and group II, respectively; group III was used as control. Results showed that, group I and group II produced 4.86 % and 6.88 % more milk than that of control (P<0.05); Meanwhile, FCM (3.5 % fat) of group I and group II was increased by 4.98 % (P<0.01) and 6.56 % (P<0.01). Change of the milk fat among the three groups were not significant(P<0.05). Average daily milk protein yield significantly was increased by 4.14 % and 2.76 % respectively (P<0.05), though the milk protein content was slightly reduced. Moreover, somatic cells of the cow in the three groups were in normal physiological range in this trial.

日粮中添加丁酸梭菌对奶牛瘤胃体外发酵及其产奶性能的影响

试验旨在研究添加不同水平丁酸梭菌对奶牛瘤胃体外发酵及产奶性能的影响。体外试验采用体外产气法,在培养底物中添加0(对照)、0.5、1.0、2.0 g/kg的丁酸梭菌,体外发酵培养48 h,测定底物营养物质降解率及体外发酵参数。动物试验选择80头产奶量和泌乳天数接近的经产荷斯坦奶牛,分为4组,按照完全随机区组设计,将相同胎次的牛随机分配到各组中,分别饲喂0(对照)、15、30、60 g/(头·d)的丁酸梭菌,试验期42 d。体外试验结果表明:底物中添加丁酸梭菌对体外48 h总产气量、pH和各挥发酸(VFA)含量(除丁酸外)无显著影响(P>0.05)。随底物中丁酸梭菌含量的增加,总挥发性脂肪酸(TVFA)浓度升高,1.0、2.0 g/kg组的丁酸含量显著高于对照组(P<0.05)。丁酸梭菌可提高瘤胃体外发酵液的氨态氮(NH3-N)浓度,1.0、2.0 g/kg组的NH3-N浓度显著高于对照组(P<0.05)。添加丁酸梭菌显著提高了底物中性洗涤纤维(NDF)降解率(P<0.05)。动物试验表明:30、60 g/(头·d)丁酸梭菌组产奶量显著高于对照组(P<0.05)。除乳脂率和乳脂产量外,日粮中添加丁酸梭菌对其余乳成分及其产奶量无显著影响(P>0.05)。与对照组相比,30 g/(头·d)组乳脂率和乳脂产量显著增加(P<0.05)。由以上两部分试验结果可知,添加丁酸梭菌可一定程度上改善体外发酵,提高营养物质中NDF降解率并提高奶牛产量和乳成分总量,且与丁酸梭菌的添加量有关,综合考虑,推荐添加量为30 g/(头·d)。

Productive Response and Reproductive Performance of Dairy Cows Subjected to Different Feeding Systems

Fifty Holstein cows (2.6 ± 1.0 lactations) in early lactation (52.6 ± 16.4 days in milk) calved in autumn and producing 34.3 (±4.4) kg milk per cow·day-1 were randomly assigned for 27 weeks to one of two treatments (feeding systems) in 10 groups (pens) of 5 animals each (5 groups/treatment). The confined treatment was a total mixed ration (TMR_100) whereas the supplemented grazing system was defined by a partially mixed ration (PMR_75) with 75% TMR and 25% oat pasture (Avena sativa L.) during the autum-winter (Period I) and alfalfa pasture (Medicago sativa L.) plus concentrate (7.0 kg per cow·day-1) (P + C) during the next spring (Period II). Milk production was daily and individually recorded throughout the trial while the chemical composition of milk was measured on individual samples every 2 weeks. Live weight (LW) and body condition score (BCS) using a scale of 1 to 5 were recorded every 3 weeks after the morning milking. Simultaneously, blood samples were taken for determinations of glucose, urea, non-esterified fatty acids (NEFA), insulin, somatotrophin (GH) and somatomedin C (IGF-I). Total DM intake was measured using the difference method four times per repetition in the months of July, August, September and October. The experimental herd was inseminated at fixed time at the start of the service (May-July) and on the return with estrus detection. The diagnosis of pregnancy was made by transrectal ultrasonography at 30 and 60 days after the start of the service. The productive data were analyzed according to a model with repeated observations in time adjusted by covariate with 2 periods and using the animal as the experimental unit. Data of DM intake were analyzed using ANOVA for 2 treatments with 5 repetitions. Cows from the TMR_100 group produced more milk (kg&#183;cow-1&#183;day-1) during Period I (33.7 vs. 32.3) and Period II (28.8 vs. 27.8) (P &#183;cow-1&#183;day-1) in Periods I (1.33 vs. 1.24) and II (1.10 vs. 0.92) and for milk protein (1.19 vs. 1.13 and 0.99 vs. 0.93). The lower energy intake of grazing cows (45.0 vs. 43.1 and 40.9 vs. 38.9 Mcal per?cow·day-1 for TMR_100 vs. PMR_75 and TMR_100 vs. P + C) coupled to the extra energy cost associated with grazing activity would explain the difference in milk production. Milk protein content (%) resulted higher (P kg&#183;cow-1&#183;day-1) in the cows of the TMR_100 group in both periods (0.69 vs. 0.34 and 0.49 vs. -0.22) was consistent with the increase in the plasmatic levels of glucose and IGF-I and the reduction in the circulating levels of GH, but not with the lack of increases in plasma insulin concentration or decreases in circulating levels of NEFA, parameters that were not affected by treatments. Despite the positive effects of TMR_100 on parameters linked to energy balance, no significant differences were detected in any of the reproductive parameters evaluated and the final rate of pregnancy was 80.0 and 91.3% for the confined and grazing system with supplementation respectively. Free milk liters over feeding costs were higher in the grazing system with supplementation compared to the confined system (18.5 vs. 15.5 l, respectively). The results indicate that the grazing system with supplementation can be economically competitive compared to the confined system of milk production.

气候变化对我国不同地区奶牛热应激的影响

全球气候变暖加剧,高温、干旱等极端性天气灾害增多,热应激严重影响我国畜牧业的发展,尤其是对奶牛养殖业更为明显。为了了解我国不同地区奶牛受热应激的影响情况,依据全国奶牛的分布情况挑选黑龙江、宁夏、湖北、上海、广东和四川6个代表性地区,利用1961—2020年的气象数据分析各地区的温度变化特征,同时采用温湿度指数(temperature humidity index,THI)分析了近10年(2011—2020年)6个地区热应激环境的总体变化规律及对奶牛产奶量的影响。结果表明:近60年来,6个地区温度变化整体均呈上升趋势,热应激环境逐渐变大。南方地区热应激出现的时间普遍早于北方,程度也相对更严重。热应激对各地区奶牛产奶量产生了不同程度的影响,其中上海地区奶牛产奶量受热应激影响最大。通过对不同地区的温度、湿度等综合分析,能够更好地了解热应激对我国不同地区奶牛生产性能的影响,对指导热应激下奶牛的饲养管理,提高奶牛养殖的经济效益提供科学依据。