大豆异黄酮对奶牛泌乳性能、血液免疫及抗氧化指标的影响

为了研究日粮中不同水平大豆异黄酮对泌乳奶牛生产性能、血液免疫及抗氧化指标的影响,试验采用单因素随机分组设计,将24头泌乳中后期‘荷斯坦奶牛’平均分为4组,进行为期42天的饲养试验。4个组中A组为对照组,B、C、D组在全混合日粮的基础上分别添加10、20和30 mg/kg的大豆异黄酮。于试验第1、14、21、28、35、42天分别按照早晚奶样的6:4比例混合后进行奶样采集,记录产奶量,并进行DHI报告分析,同时对血样进行血常规及血清指标测定。结果表明大豆异黄酮能显著提高奶牛产奶量。饲喂30 mg/kg大豆异黄酮的奶牛第42天的产奶量与同期对照组相比提升了21.8%(P<0.05),乳蛋白含量和乳脂率无显著变化。大豆异黄酮可以减少乳中淋巴细胞和单核细胞分布,对多形核白细胞(PMN)的数量分布无显著影响。饲喂大豆异黄酮28天后,奶牛血液中红细胞数(RBC)的数量开始显著提升(P<0.05),但白细胞数(WBC)变化不明显。试验28天后血清中白介素4(IL-4)表达水平有显著提高(P<0.05),35天后抗氧化指标谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(T-SOD)酶活性均有显著提高(P<0.05)。试验结果表明在日粮中添加大豆异黄酮能增加奶牛的IL-4水平和抗氧化酶活性,并改善奶牛的产奶性能。

Precise Calculation System of Total Mix Ration for Lactating Cow

[Objective] The paper was to precisely predict nutrient requirements and optimize ration formula, and explore the inherent feature of ration optimization of dairy cow. [Method] Based on cornell net carbohydrate and protein system （CNCPS） with integrating dynamic prediction models on main nutrient requirements of dairy cattle recommended by NRC （2001） and the CNCPS parameter database accumu- lated by Chinese feed database, the ration nutrient requirement dynamic calculation and total mixed ration （TMR） formula optimizing system for Holstein dairy cow was developed using FOXPRO database system and parametric linear programming algo- rithm. [Result] By optimizing a specific cow ration and analyzing its completed nutri- ents, the results showed that this system could entirely consider a lots of nutrient balances, such as concentrate fraction and forage fraction balance, rumen degrad- able protein and rumen undergradable protein balance, crude protein and lactation net energy balance, fibrous substances （ADF, NDF） and non-fiber carbohydrates （NFC） balance, calcium and phosphate balance, electrolytes balance and trace ele- ment balance etc., and could also calculate intestinal amino acid flow in terms of different models. [Conclusion] By using dynamic mathematical equations and comput- erized program, it can be realized for the ration formula design of lactating cow with all-round interoperable but mutual-constraining each other among ration nutrients.

Effect of Metallothionein on Cell Cycle,Apoptosis Rate and Subsets Distribution of Lymphocytes in Peripheral Blood of Dairy Cattle under Heat Stress

[Objective] This study aimed to research the effect of metallothionein on cell cycle, apoptosis rate and subsets distribution of lymphocytes in peripheral blood of dairy cows under heat stress, so as to perfect the regulative mechanism re- searches of MT to anti-heat stress. [Method] Twenty lactating Chinese Holstein cows were randomly divided into four groups （A, B, C and D）, and injected with 0, 4.0, 8.0 and 12.0 mg Zn-metallothionein, respectively by intravenous route. Blood sam- ples were collected at 1＂, 16~, 31~, 46~ and 61~ day, and the dynamic changes of cell cycle, apoptosis rate and subsets distribution of lymphocytes were determined. [Result] The apoptosis rate of cells in group B and C was lower than those in group A by 26.63% （P〉0.05） and 24.84% （P〉0.05） respectively. The number of cells in the Gc/G1 phage in trial groups was increased and the number of cells in the S and GJM phages tended to decrease, but there were no significant differences （P〉 0.05）. The number of CD3~ T cell in three trial groups was greater than those in group A by 7.02% （P〉0.05）, 5.45% （P〉0.05） and 3.85% （P〉0.05） respectively, while the number of CD4~ T cell in trial groups was higher than those in control group by 31.04% （P〈0.05）, 35.68% （P〈0.05） and 39.34% （P〈0.05） respectively. The number of CD8＇ T cell and the levels of CD4＊/CD8~ in trial groups were increased observ- ably, but significant difference （P〈0.05） was observed in the levels of CD4~/CD8~ between groups A and C only. It demonstrated that exogenous Zn-metallothionein can decrease apoptosis rate, improve cell cycle and regulate subsets distribution of lymphocytes in dairy cattle in a dose-dependent manner. [Conclusion] This study will provide scientific basis for safe utilization of MT in dairy industry.

Genetic Parameters for Yields and Reproductive Traits of Chinese Holstein Cows in Heilongjiang Province

[Objective] This study aimed to estimate the genetic parameters for milk yield, fat percentage, fat yield and age at first freshening of Chinese Holsteins first lactation cows in Heilongjiang under frigid-temperature and temperature zone. [Method] Records of yield and reproduction from 8 868 Chinese Holstein first lacta- tion cows from 21 herds were utilized to evaluate genetic parameters for Hei- Iongjiangs＇ Chinese Holsteins. Restricted maximum likelihood （REML） method was used with an animal model. [Result] The heritabilities were 0.16 to 0.34 for yields and fat percentage, 0.38 for reproduction （age at the first freshening）, which were similar to estimates for temperate areas from similar methods, except for constituent percentage. Also, the estimates of genetic correlation were high between milk yield and fat yield （0.97）, but were low between milk yield and fat percentage （-0.24）, age at the first freshening （-0.29） and generally antagonistic. [Conclusion] Thus, es- timates of genetic parameters in this frigid and frigid-temperate environment did not differ appreciably from those that occur in temperate dairy areas.

The Detection of STAT1 Gene Influencing Milk Related Traits in Turkish Holstein and Jersey Cows

The main purpose of this study was to detect an association of cytoplasmic signal transducers and activators of transcription-1 （STAT1） with milk production traits in 472 Holstein and 283 Jersey cattle breeds of Turkey. This gene, located on chromosome 2, was chosen due to its role on development of mammary gland. A polymorphism of selected 314 bp allele fragment was detected by the restriction fragment length polymorphism analysis of polymerase chain reaction-amplified fragments （PCR-RFLP） method and also confirmed by DNA sequencing. The association tests were conducted between STAT1 genotypes and some economically important dairy traits. The genotypes for C/T as a single nucleotide polymorphism （SNP） were identified at interval 60 cM to 63 cM. The effects of STAT1 gene on milk production traits were not significant in Holstein cows, although animals with CT genotypes showed fairly close to significant value for the corrected 305 d milk yield. However, Jersey cows with/7＂ genotype were 2.07 kg higher for test-day milk yield （P 〈 0.05）, 0.13 kg for fat yield （P 〈 0.01） and 0.07 kg for protein yield （P 〈 0.05） compared with animals having CC and CT genotypes. Definitely, the further research should be conducted to search this gene intensively with larger samples to identify polymorphism and any association between the economically important traits and genotypic class in Holstein cows. Finally, based on the findings, it was concluded that STATI gene might be used as a potential candidate gene to improve milk yield and milk fat and protein contents in dairy cows breeding programs.

Effects of Feeding Siamese neem leaves and Zanthoxylum Pods, on Dry Matter Intake, Dry Matter Digestibility, Milk Production and Composition in Thai Holstein Dairy Cows, Fed Rice Straw as Fiber Source

The plant secondary metabolites （PSM） are highly sought compounds for use as an alternative to conventionally used feed additives in animal production these days; Siamese neem leaf （Azadirachta indica A. Juss. var. siamenses Valeton） and Zanthoxylum pods （Zanthoxylum piperatum） are known to contain numerous such compounds.The objectives of this study were to determine effects of feeding Siamese neem leaf and Zanthoxylum pods as feed additives on dry matter intake （DMI）, dry matter digestibility （DMD） and milk production and milk composition. Lactating Thai Holstein cows （n = 8） were arranged in two replicates of 4 x 4 Latin square designs, housed in individual stall, treatments consisted of Siamese neem 0.5 and 1.5 g kgl dry matter （DM）, ZanthoxylumO. 1 and 0.5 g kg1 DM added to the total mixed ration （TMR）. TMRand drinking water were provided ad lib. There were no significant differences （P 〉 0.05） in DMI and crude protein （CP）, acid detergent fiber （ADF）, neutral detergent fiber （NDF） digestibility, milk production and composition among the treatments.However, significant difference （P 〈 0.05） was observed in dry matter （DM） and ether extract （EE） digestibility. Though statistically non-significant, Zanthoxylum at higher dose level tended to show low DMI （14.85 kg） in cows, while promotingmarginally higher milk （14.18 kg） production as compared with lower dose levelwhere DMI and milk production were 16.14 kg and 13.83 kg.This indicated that Zanthoxylum has a potential to improve feed digestion in dairy cows when used as additives.

Effect of Palm Oil By-pass Fat on Milk Composition of Early Lactation Holstein Cows Fed Whole Plant Corn Silage during Dry Season

The objective of this study was to investigate the effect of Palm Oil By-pass Fat （POBF） on milk composition of early lactation Holstein during dry season, 24 postpartum Holstein （1 d-14 d） were selected and align to two groups according to CRD experimental design; each group included 12 Holstein cows. The control received by-pass fat 0 g/h.d, the experimental group received by-pass fat 300 g/h.d. The results shown, DMI and yield of milk did not be affected with supplementation of by-pass fat, however, milk protein increased by 6.71%, milk fat increased by 8.16%, lactose increased by 0.22%, SNF increased by 1.98%, TS increased 4.08%; digestibility of diet protein decreased by 6.62%, digestibility of EE decreased by 7.96%, digestibility of NDF and ADL decreased by 1.36%, 8.97% respectively, digestibility of DM and OM decreased by 4.42, 3.07 percentage units; amount of C4-C17 milk fatty acids showed a decreased tendency, that of CIs-C22 showed an increased tendency, the milk CLA increased significantly （P 〈 0.01）. To sum up, supplementation of by-pass fat for early lactation Holstein is an important measure to balance energy and sustain milk yield and quality.

Practical Application of Diets Rich in Ground Linseed to Enhance Omega-3 Milk Production in Holstein Dairy Farms Located in Northeast Iran

In an attempt to enhance organic omega-3 milk production, a practical study was performing in 7 Holstein dairy farms in Northeast Iran. The experiment was conducted at the ＂ShafashirToos industrial dairy farmers production and distribution cooperative＂ located in Northeast Iran, between June 2010 and December 2010. In Golshid-Mashhad Co., cows were fed with no linseed containing diets （NO-Lin）, while in the other farms （Hanaei Co., Ghasemi Co., Taheri Co., Teliseh Co., Arasp Co. and Navingholshid-Khorasan Co.）, cows were fed diets containing 9% ground linseed （Lin）. Cows were used in a randomized complete block experimental design. Diets were provided as TMR. Concentration of fat, protein and lactose in milk was measured. Milk fat extraction and fatty acid separation were determined. There were no differences in the most of the milk fatty acid profiles of cows in farms that received ground linseed but feeding Lin diets compared with NO-Lin, significantly decreased （P 〈 0.05） C8：0-C16：0 concentration and it increased those of C 18：1 n9trans, C 18：1 n9cis, C 18：2 trans and C 18：3 n3. As a result, farms with Lin diets had better milk fatty acid profiles with doubled in a-Linolenic acid concentration and increased in mono and polyunsaturated fatty acids and decrease in medium chain and saturated fatty acids compared with those of the NO-Lin diet. These results clearly demonstrate the possibility for sustainable production of organic omega-3 milk with levels ofC18：3 FA up to 2.4 times higher than typical levels in dairy fat. The manufacture of omega-3 enriched milk and milk products could supply dietary fatty acids at levels that may henefit health, without the need for unrealistic changes to eating habits.

Hormonal （Thyroxin, Cortisol） and Immunological （Leucocytes） Responses to Cistern Size and Heat Stress in Tunisia

This study was designed to determine the effects of heat stress on plasma leucocytes, Thyroxin （T4） and cortisol concentrations in dairy cows with small and large cistern under hot climate. This experiment was carried out in 2006, in North Tunisia, using a randomized block design per udder cistern size, using 60 Holstein cows. Cows were classified according to udder cistern size by ultrasonography as large-cisterned （44 ±13 cm2; LC） and small-cisterned （21 ± 8 cm2; SC）. The experiment was carried out in two different periods： spring （Apr. 5 （D1）） and summer （July 19 （D2）, Aug. 19 （D3） and Sept. 19 （D4））. On each test day, temperature and relative humidity data were registered hourly and cows＇ blood was sampled from the jugular vein to determine serum concentrates of cortisol and T4. Leucocytes （lyrnphocytes, eosinophils, neutrophils and monocytes） were counted differentially, and percentages of lymphocytes relative to total counted cells were calculated. Mean temperature-humidity index （THI） values were 62 ±2, 79 ±2, 84 ±2, and 77 ±1 in DI, D2, D3, and D4, respectively. Lymphocyte incidence relative to total cell counts and T4 concentrations were affected by test day （P 〈 0.001）. Lymphocytes （%） were significantly less in hotter months. During summer, T4 concentration at D2 （87.4 nmol/L） was higher relative to concentrations at D3 （42.8 nmol/L） and D4 （53.5 nmol/L）. T4 concentrations were higher （P 〈 0.01） in SC cows （67.7 ±0.1 nmol/L） compared to LC cows （52.7 ±0.1 nmol/L）. Cortisol concentration was effected neither by test day nor by cistern size. However, the decrease of lymphocyte concentration during summer compared to spring could be considered as an evidence of the suppression of cows＇ immune system under heat stress.

Effect of Delayed Insemination on Holstein Cows＇ Reproductive Performance

Holstein cows＇ fertility has decreased in the last decade, creating a need for new management methods to improve the reproductive performance which in this case was defined by pregnancy rates and number of artificial inseminations （AI） per pregnancy. Previous studies showed that deliberately delaying rebreeding until after peak lactation can improve reproductive performance compared with the traditional rebreeding in early lactation. The objective was to compare the reproductive performance of cows in consecutive lactations of different lengths. The reproductive performance （pregnancy rate and number of insemination to pregnancy） of 62 Holstein cows involved in a 16 months extended lactation trial was recorded and compared with the reproductive performance of the previous and following 10 months lactation of the same cows. It was hypothesized that a late rebreeding （at eight months, 16 months lactation） will improve the reproductive performance compared with an early rebreeding （at two months, 10 months lactation） in the previous lactation, and it will have no negative effect on the reproductive performance in the following lactation with an early rebreeding. The results showed that the pregnancy rates were similar for the 16 months lactation and the previous and following 10 months lactations, while the number of AI to pregnancy was increased in the 10 months lactation, following by the 16 months lactation. The use of the double AI technique did not improve pregnancy rates compared with a single AI per estrus, and induced confusion, as how to report the herd reproductive performance. To conclude, the reproductive performance was similar between the heifers, primiparous and multiparous cows, and between 10 months and 16 months lactations.

The Main Causes of Calf Mortality in Dairy Farms in Poland

Calf mortality is one of important problems of calf rearing in dairy farms worldwide. Besides, several noninfectious factors, such as management around birth, colostrum management, calf housing, feeding system, hygiene and pathogens, play an important role in calf rearing. The aim of the study was to show the most common causes of mortality of calves up to 90 d of their lives. Some data are available concering calf rearing management on small and medium size dairy farm typical for Polish regions. The research was conducted in seven selected herds of Polish Holstein-Friesian cows located in South of Poland. Data on calves mortality covered the period of three years from 2004 to 2007 and were collected using medical documentation and medical inquire in the farms. All evidence was enrolled untill three months of age of calves. There were 1,800 calves tested. The influence of such factors as maintaining system （free stalls barn and stalls barns）, feeding systems and herd size on falls of calves was examined. Overall, mortality throughout the three months of study period was diarrhea, which increased the risk of death among calves younger than 90 d of age. Also, respiratory system disorders were the common cause of loss of calves. The calf mortality rate during 90 d in all herds registered in free stall barns was 61% and in stalls barns was only 29%. Effect of pneumonia in free stall barns was 18% and in stall barns was 29%. In all groups, calf mortality rates increased with increasing herd size.

Effects of Rumen-protected Methionine on Rumen Fermentation, lactation Performance and Plasma Characteristics in Dairy Cows

The objective was to evaluate effects of rumen-protected methionine （RP-Met） supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty-four multiparous （2.2 - 0.40 parity） Holstein dairy cows, averaged 620 ± 12.3 kg of BW, 68 ± 2.5 day in milk and daily milk production averaged 26.0 ±0.3 kg/cow were used in a replicated 4 × 4 Latin square experiment. The treatments were： control （without RP-Met）, LRP-Met, MRP-Met and HRP-Met with 20, 40 and 60 g RP-Met per cow per day, respectively. RP-Met was hand-mixed into the top one-third of the daily ration. Experimental periods were 30 days with 15 d of adaptation and 15 d of sampling. Dry matter （DM） intake and milk yields were not affected （P 〉 0.05） with increasing RP-Met supplementation. Yields of 4%FCM, ECM, milk fat and milk protein were higher （P 〈 0.03） for RP-Met supplementation than control and were quadratically （P 〈 0.05） changed due to the higher percentage of milk fat and protein for RP-Met supplementation than control （P 〈 0.03）. Ruminal pH tended to be lower （P = 0.071） for RP-Met supplementation than control, whereas total VFA concentration tended to be higher （P = 0.086） for RP-Met supplementation than control. Ratio of acetate to propionate decreased linearly （P = 0.001） from 4.01 to 3.57 as RP-Met supplementation increased due to the increase in propionate production. Digestibilities of DM, OM, CP, NDF and ADF in the total tract were higher （P 〈 0.05） for RP-Met supplementation than control and were quadratically （P 〈 0.05） increased with increasing RP-Met supplementation. Plasma concentrations of glucose not affected （P 〉 0.05） with RP-Met supplementation, Plasma concentrations of non-esterified fatty acids （NEFA） were significantly lower （P = 0.017） for RP-Met supplementation than control and were linearly （P = 0.011） changed. Plasma concentrations of beta-hydroxybutyrate tended to be lower （P = 0.068） for RP-Met supplementation than control and were linearly （P = 0.001） changed. The present results indicate that supplementation of diet with RP-Met improved the content of milk fat and protein, rumen fermentation and feed digestion, decreased plasma concentrations of NEFA. It was suggested that the RP-Met stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum RP-Met dose was about 25 g RP-Met per cow per day.

Comparative Study of the Flavor Compounds in two Different Milk with SPME-GCMS

The flavor is very important in the dairy industry because it decides on the acceptance of milk and other dairy products. And the flavor compounds in two different milk were analyzed with SPME-GCMS. At present, the milking mode includes automatic milking and manual milking in cat- tle farm. Milk samples, collected from six healthy early/mid-lactation Holstein cows, were analyzed by static headspace （SH） and solid phase microextraction （SPME） combined with gas-chromatogra- phy and mass spectrometry （GCMS） in this paper. The result showed that the aroma compounds in milk （automatic milking） were more than that of milk （manual milking）, but the off-flavor com- pounds in milk （automatic milking） were less than that of milk （manual milking）. So to preserve the good flavor, the milk should be extruded with the automate milking.