大理地区奶牛隐性乳房炎发病规律调查

本调查于2004年7~11月在大理地区奶牛主要养殖区内进行,共选择了10个自然村,随机选取临床健康、乳汁无肉眼可见异常变化的泌乳奶牛106头;应用奶牛体细胞计数法(Little和plastrige法)、加州乳房炎试验(C·M·T)法、溴麝香草酚蓝试验(B·T·B)法进行检测。结果为:奶牛隐性乳房炎阳性率为44·00%~61·73%,平均57·55%;乳区阳性率为23·58%~32·08%,平均29·24%。隐性乳房炎的发病率与奶牛的年龄、胎次、乳区间有一定的关系,但差异不显著(P>0·05);与奶牛泌乳量和季节间的关系密切,呈显著差异(P<0·05);患病乳区数发病率间呈极显著差异(P<0·01),患病乳区数与其发病率间呈显著负相关(P<0·05),但患病乳区以一个为主;C·M·T法阳性反应强度+、++、+++乳区数间呈极显著差异(P<0·01),乳区发病率按反应强度由低至高排列为+>++>+++。     

饲粮中添加碘对奶牛产奶性能、垂体——甲状腺轴分泌机能的影响

选用15头健康成年黑白花奶牛,随机分成三组,按3×3有重复拉丁方设计进行饲养试验,试期三个月,共有三个处理:(A_1)饲粮中添加 K110mg/头·日,(A_2)添加 K120mg/头·日,(A_3)常规饲粮(对照),研究饲粮中添加碘对奶牛产奶性能、垂体——甲状腺轴分泌机能的影响。结果表明:处理 A_1奶牛产奶量和标准乳量分别为23.29±0.51kg/头·日和20.53±0.51kg/头·日,处理 A_2则分别为23.41±0.34kg/头·日和20.58±0.33kg/头·日,均极显著地高于对照 A_3的21.58±0.50kg/头·日和18.70±0.57kg/头·日(P<0.01),A_1、A_2处理之间差异不显著。三处理乳脂率分别为(A_1)3.21±0.077,(A_2)3.20±0.079,(A_3)3.10+0.081,两个补碘处理虽均高于对照,但统计上不够显著。三处理之间乳中干物质含量和非脂干物质含量均未发现显著性差异。A_1、A_2处理血清中 T_4含量均显著高于 A_3(P<0.05),但 A_1、A_2之间无显著差异(P>0.05);血清 T_3含量 A_2极显著地高于 A_3(P<0.01),A_1显著高于 A_3(P<0.05),A_1、A_2之间差异不显著(P>0.05);血清游离甲状腺变化情况与甲状腺素的变化相似。A_1、A_2血清中 TSH 含量均极显著地高于 A_3,但 A_1、A_2之间未发现显著差异(P>0.05)。提示日粮中添加适量碘可以改善奶牛垂体——甲状腺轴的分泌机能从而提高产奶性能,饲粮碘稍微过量对甲状腺机能、产奶性能均无不良影响。     

过瘤胃赖氨酸和过瘤胃蛋氨酸对泌乳早期奶牛生产性能影响的研究

试验选用荷斯坦泌乳早期奶牛100头,随机分为对照组和试验组。两组基础日粮相同,但试验组奶牛在试验前期60d添加过瘤胃赖氨酸(RPLys)24g/头·d、过瘤胃蛋氨酸(RPMet)15g/头·d,试验后期60d添加RPLys48g/头·d、RPMet30g/头·d。结果表明,试验组产奶量平均提高1.25kg,试验前期增幅达2kg(P<0.05),试验中后期差异不显著(P>0.05),试验组和对照组的乳脂率和乳蛋白率差异不显著(P>0.05)。     

包膜甜菜碱与有机铬复合物对夏季奶牛产奶性能和血液生化指标的影响

旨在研究包膜甜菜碱和有机铬复合物对夏季奶牛产奶性能和血液生化指标的影响。选择年龄、胎次、泌乳时间和产奶量相近100头泌乳牛,随机分为对照组和试验组,每组50头,对照组饲喂原奶牛场配方日粮,试验组在每天早晨TMR日粮中添加50 g/d包膜甜菜碱和有机铬复合物。结果:与对照组相比,试验组奶牛采食量显著提高(P<0.05),牛奶中体细胞含量显著降低(P<0.05);奶牛乳酸脱氢酶(LDH)含量显著提高(P<0.05);磷酸肌酸激酶(CPK)含量显著降低(P<0.01),谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)含量有上升趋势,丙二醛(MDA)、碱性磷酸酶(ALP)含量有下降趋势,但差异均不显著。试验表明包膜甜菜碱和有机铬具有提高热应激期奶牛采食量、促进代谢和蛋白质合成、缓解奶牛热应激的作用。     

奶牛尿素中毒的病例介绍

(一)发病情况 2005年6月9日,本案畜主的两头奶牛随牛群归牧,回到家20分钟左右出现异常表现,30分钟左右,2头奶牛相继死亡.后经过现场查看、了解以及生前表现和解剖变化,确定2头奶牛的死亡原因是尿素中毒.     

王不留行提取物对泌乳中期奶牛血清生化指标、泌乳相关激素及免疫功能的影响

试验旨在研究王不留行提取物对泌乳中期奶牛血清生化指标、泌乳相关激素及免疫功能的影响。选用胎次(2~4胎)、体重、产奶量均相近的泌乳中期中国荷斯坦奶牛32头,随机分为4组,每组8头,分别饲喂王不留行提取物添加水平为0(对照组)、5.7 g/(头·d)(低剂量组)、19 g/(头·d)(中剂量组)、38 g/(头·d)(高剂量组)的试验日粮。预试期7 d,正试期35 d。结果表明,与对照组相比,各剂量组血清中总蛋白、白蛋白含量均无明显变化(P>0.05),其中在第30天时,血糖含量呈升高趋势,甘油三酯、尿素氮含量呈下降趋势,但差异均不显著(P>0.05);与对照组相比,各剂量组血清中催乳素和生长激素水平有一定程度的提高,其中中、高剂量组在第30天时差异显著(P<0.05);与对照组相比,各剂量组血清中IgA、IgG含量呈升高趋势,而IgM含量呈下降趋势,但差异均不显著(P>0.05)。综上所述,日粮中添加王不留行提取物可改善奶牛机体的能量代谢水平及蛋白质的利用率,促进体内脂类代谢,提高产奶量,建议泌乳中期奶牛日粮中王不留行提取物添加量为19~38 g/(头·d)。     

围产期添加刺五加对奶牛生产性能的影响

本试验以围产期奶牛为研究对象,刺五加水提取物为试验材料,采用完全随机化设计,随机分为2个处理组,每个处理组5个重复,每个重复2头,从奶牛分娩前2周饲喂刺五加水提取物(0、50 mg/kg),研究其对奶牛产奶量及血液生化指标及血清中激素的影响。结果表明:试验组奶牛产乳量大大提高,与对照组相比差异显著(P<0.05);刺五加水提取物添加组中血清血糖、白蛋白及血浆总蛋白含量显著高于对照组(P<0.05),而血清胆固醇、谷丙转氨酶、谷草转氨酶、尿素氮及甘油三酯与对照组差异不显著(P>0.05)。血清中生长激素(GH)和催乳素(PRL)含量显著高于对照组(P<0.05),而胰岛素样生长因子-I(IGF-Ⅰ)含量与对照组差异不显著(P>0.05)。试验结果说明,添加刺五加水提取物可以提高奶牛的产奶量并可改善乳品质,并对奶牛机体健康无不良影响。     

奶牛尿素中毒的病例介绍

（一）发病情况 2005年6月9日，本案畜主的两头奶牛随牛群归牧，回到家20分钟左右出现异常表现，30分钟左右，2头奶牛相继死亡。后经过现场查看、了解以及生前表现和解剖变化，确定2头奶牛的死亡原因是尿素中毒。     

酵母培养物对奶牛干物质采食量、产奶量及血清指标的影响

试验旨在研究纽润康酿酒酵母培养物对奶牛的干物质采食量、产奶量及血清指标的影响。试验组和对照组各300头奶牛,对照组奶牛饲喂基础日粮,试验组奶牛在基础日粮基础上添加120 g/(头·d)酿酒酵母培养物。结果显示,试验组奶牛产奶量显著提高1.66 g/(头·d),平均干物质采食量显著提高0.72 g/(头·d)。试验组奶牛血清中谷丙转氨酶活性极显著低于对照组(P<0.01),血清免疫球蛋白G (IgG)含量极显著高于对照组(P<0.01)。日粮中添加酵母培养物能够极显著提高超氧化物歧化酶(SOD)活性(P<0.01),显著提高奶牛机体的总抗氧化能力(T-AOC)(P<0.05)。研究表明,日粮中添加酿酒酵母培养物可提高奶牛机体的免疫力和抗氧化能力。     

高剂量锌对奶牛生产性能和血液指标的影响研究

选择泌乳中后期的中国荷斯坦奶牛24头,分为4组,每组6头,对照组饲喂基础日粮(锌水平71 0mg/kg日粮干物质),试验Ⅰ组、Ⅱ组和Ⅲ组在对照组基础上分别添加300、500和800mg/kg的锌(以饲料级硫酸锌的形式)。研究高锌对奶牛生产性能和血液理化性质的影响。结果表明:添加高锌对产奶量无显著影响(P>0 05),不影响乳蛋白含量和乳脂率(P>0 05),但乳锌含量分别提高了66 91%(P<0 01)、104 83%(P<0 01)和115 7%(P<0 01)。添加高锌对血清碱性磷酸酶活性无明显影响(P>0 05),但血清锌水平分别提高了65%(P<0 01)、120 77%(P<0 01)和162 31%(P<0 01);血清白蛋白和血清尿素氮水平与对照组均无明显差异(P>0 05);血红蛋白含量和红细胞比容与对照组相比均无显著差异(P>0 05)。     

The effect of age on erythrocyte magnesium concentrations of dairy cows during late pregnancy and early lactation

Blood samples were taken at weekly intervals from fifty four dairy cows (mainly Friesians and Jerseys) during the periods 8 weeks before and 8 weeks after calving. The cows were divided into two age groups; Group 1 consisting of 26 cows 2 1/2 to 4 years old and Group 2 consisting of 28 cows over 4 years old.The changes in erythrocyte magnesium (EMg) and plasma magnesium (PMg) concentrations before and after calving were expressed as the slope of each blood parameter regressed on weeks. The post-partum EMg concentration slope (increase) was greater (P<0.05) in the older cows than in the young ones. The older cows also had higher (P<0.05) mean EMg concentrations than the young cows. Between cow EMg concentration variations were significant (P<0.05) in both age groups while the weekly EMg concentration variations were only significant (P<0.05) in the older cows after calving. Age did not influence the changes in PMg concentrations before or after calving. Nor did the PMg concentrations vary significantly either between cows or between weeks.     

雏鸭实验性镉中毒的病理学研究

用114只3日龄肉鸭作急性、亚急性镉中毒的病理学观察。急性镉中毒的LD50为289mg/kg体重。灌服1／10、1／20、1／30LD50剂量作亚急性毒性试验，每日服药一次，试验期6周，其发病率分别为11／11、11／11和3／11，死亡率分别为10／11、7／11和3／11。中毒鸭表现为生长缓慢，Hb、RBC和PCV显著降低，死前多呈现呼吸困难。尸体剖检和病理组织学变化主要是纤维素性心外膜炎、心肌变性、间质性心肌炎，纤维素性肝周围炎、肝细胞严重脂变、间质性肝炎，纤维素性肺浆膜炎、支气管肺炎，气囊积液、气囊壁水肿和钙化，卡他性肠炎以及脑充血、出血等。透射电镜观察，心肌纤维、肝细胞和肾曲管上皮细胞内线粒体严重肿胀，嵴断裂、溶解。肝细胞还可见糖元颗粒明显减少，脂滴增多等。测得亚急性组织肝脏和肾脏的镉含量，试验组与对照组之间有极显著差异（P＜0．01）。试验组口服镉含量高的与镉含量低的之间亦有显著或极显著差异（P＜0．05或P＜0．01）。     

Influence of body condition score on carcass characteristics and subprimal yield from cull beef cows.

Mature beef cows (n = 83) were slaughtered to measure the influence of body condition score (BCS) on carcass characteristics and subprimal yields. All cows were weighed and assigned BCS, based on a 9-point scale, 24 h before slaughter. Cows were slaughtered, and, after a 48-h chilling period, quality and yield grade data were collected on the left side of each carcass. The right side was quartered, fabricated into primal cuts, and weighed. Each primal cut was further processed into boneless subprimal cuts, minor cuts, lean trim, fat, and bone. Cuts were progressively trimmed to 6.4 and 0 mm of external and visible seam fat. Weights were recorded at all stages of fabrication, and subprimal yields were calculated as a percentage of the chilled carcass weight. Live weight, carcass weight, dressing percentage, fat thickness, longissimus muscle area, muscle:bone ratio, and numerical yield grade increased linearly (P = .0001) and predicted cutability and actual muscle-to-fat ratio decreased linearly (P = .0001) as BCS increased from 2 to 8. Carcasses from BCS-8 cows had the most (P<.05) marbling. The percentage of carcasses grading U.S. Utility, or higher, was 16.7, 20.0, 63.6, 43.3, 73.3, 100.0, and 100.0% for cows assigned a BCS of 2, 3, 4, 5, 6, 7, and 8, respectively. At 6.4 mm of fat trim, carcasses from BCS-5 cows had higher (P<.05) shoulder clod yields than carcasses from cows having a BCS of 6, 7, and 8. Carcasses of BCS-2 cows had lower (P<.05) strip loin yields than carcasses from BCS-3, 4, 5, 6, and 7 cows. Top sirloin butt yields were higher (P<.05) for carcasses of BCS-2, 3, 4, and 5 cows than those of BCS-6, 7, or 8 cows. Carcasses from BCS-7 and 8 cows had lower (P<.05) tenderloin and inside round yields than carcasses of BCS-5, or less, cows. At both fat-trim levels, carcasses from BCS-5 cows had higher (P<.05) eye of round yields than cows assigned BCS of 2, 7, or 8. When subprimal cuts were trimmed to 6.4 mm of visible fat, carcasses from BCS-5 cows had higher (P<.05) total lean product yields than cows assigned a BCS of 2, 4, 7, and 8. Regardless of fat trim, total fat yields increased (P = .0001) and total bone yields decreased (P = .0001) linearly as BCS increased from 2 to 8. Although carcasses from BCS-5 and 6 cows had the highest yields of lean product, cattle producers and packers may benefit most by marketing and(or) purchasing BCS-6 cows because a higher percentage of their carcasses had quality characteristics deemed desirable for fabrication into boneless subprimal cuts.     

Characteristics of Metacarpal Bones from Cows of Different Ages and Weights

Metacarpals from 59 Angus/Gelbvieh rotationally crossed cows were studied to determine whether bone loss occurs in beef cows between 33 and 153 mo of age. Bone loss or a change in bone composition could affect lean meat yield and proportions of carcass components such as ash. With the exception of 18 single-calf cows that were fed a high concentrate diet after their calves were weaned at 120 d of age, all cows with suckling calves grazed the same pastures. Calves from pasture-fed cows were weaned 46 d before the cows were slaughtered on October 23. Although carcasses from 153-mo-old, pasture-fed cows were heavier (P<0.01) than those from 33-mo-old, pasture-fed cows, no differences (P>0.05) in metacarpal weight, length, cortex shaft area, moisture in cortex, or ash in cortex were observed. Weight and length of metacarpals from 33-mo-old pasture-fed cows with 226.8-kg carcasses were similar (P>0.05) to those from 33-mo-old concentrate-fed cows with 409.3-kg carcasses. Metacarpals from the concentrate-fed, single-calf cows were then compared with those from 129-mo-old cows. Again, no differences (P>0.05) in weight or length of the bones were present. Low correlation coefficients obtained by pooling data for all 59 cows confirmed that no differences (P>0.05) in weight or length of bones existed among animals varying greatly in weight or age. Because complete calcification of the epiphyseal growth plates on the metacarpals occurs prior to 33 mo of age, no change in length was expected. However, our findings that no change in metacarpal weight or bone cortex composition occurred with large changes in age or weight are of interest. Within Angus/Gelbvieh crossed cows, the lean:bone ratio is based entirely on changes in muscle mass because bone mass remains constant. In addition to muscle mass, changes in fat content influence bone percentage in the carcass.     

肉鸡实验性镉中毒的病理学研究

用3日龄雏鸡150只，作急性和亚急性镉中毒病理学观察，急性毒性的LD50为84．48mg/kg体重。1／10，1／20，1／30，1／40LD50和基础组作亚急性实验，实验期6周，死亡和存活鸡之比分别为4／12，3／12，3／12，3／12和0／12。死亡鸡的主要病变为肺充血、出血及炎症，肝变性及肝周炎，心肌变性及心外膜炎以及肠道卡他等。电镜检查亚急性存活病例，主要肝、心、肾细胞内的线粒体减少及萎缩，肝内质网增生、断裂，肾小球基底膜节段性增厚。亚急性试验鸡的肝和肌肉中镉含量极显著差异高于对照组（P＜0．01），而肝中铁含量试验组则极显著低于对照组(P＜0．01）。     

Parathion poisoning in cattle (author's transl)]

In a herd of dairy cattle half of the cows showed symptoms of acute poisoning. Blood- and hair samples were taken from seven of the cows, of which two did not show any clinical symptoms. The cholinesterase activities were in all the blood samples decreased to about 10 per cent of normal and parathion was found in all hair samples. The cholinesterase activities rose gradually during a 31/2 month period to the lower part of the normal range. Parathion was found in samples from the inner walls of the cowstable, and it was concluded that the poisoning was probably due to parathion spraying in the stable, while a suspicion of winddrift as a source of poisoning was rejected as less probable.     

Benchmarking sensory off-flavor score,off-flavor descriptor and fatty acid profiles for muscles from commercially available beef and dairy cull cow carcasses

The first objective of this research was to benchmark off-flavors from 9 muscles and fatty acid profiles from the longissimus muscle from commercially identified fed and non-fed cull beef and dairy cows and A-maturity, USDA Select steers (n=15 each). The second objective of this study was to determine the relationship between fatty acids and off-flavor score in the longissimus muscle. There was a trend (P=0.06) for a muscle by carcass group interaction for sensory off-flavor detection. Muscles from non-fed beef cows had the greatest incidence of off-flavor detection while muscles from A-maturity, Select steers had the lowest incidence of off-flavors. No relationship (P > 0.10, R² < 0.08) was found to exist between the fatty acid profile of the longissimus muscle and sensory off-flavor detection. Commercially identifying cull cows as fed or non-fed prior to harvest may be a beneficial method to reduce off-flavors in muscles that may be used beyond ground products.     

Parturition invokes changes in peripheral blood mononuclear cell populations in Holstein dairy cows naturally infected with Mycobacterium avium subsp. paratuberculosis

Johne's disease (JD) is characterized by a protracted period of subclinical infection. Infected cows may remain in the subclinical state until stressors such as parturition and lactation invoke more clinical signs of disease. The objective of this study was to evaluate changes in the percentages of CD4(+), CD8(+), and gammadelta T-cells, B-cells, monocytes, as well as the expression of the activation marker, CD5, on these cell subpopulations in the peripheral blood of dairy cows naturally infected with Mycobacterium avium subsp. paratuberculosis (MAP) during the periparturient period. Peripheral blood mononuclear cells (PBMCs) were collected from 3 wk pre- to 4 wk post-calving and freshly isolated or cultured for 7d. Day 7 cultures were infected with live MAP at a 10:1 MOI (bacteria to adherent PBMC), and cultures were incubated for an additional 24h. Fluorescent antibody labeling of lymphocyte subsets and monocytes was conducted and analyzed with flow cytometry. Freshly isolated PBMCs from subclinical cows expressed a greater (P<0.05) percentage of CD8(+) and gammadelta T-cells compared with clinical cows. The percentage of CD4(+) T-cells increased (P<0.08) in clinical cows as parturition approached. During the postpartum period, clinical cows had greater (P<0.05) CD4:CD8 ratios compared with subclinical and control cows. After 8d, uninfected PBMCs from clinical cows had greater (P<0.05) percentages of CD14(+) cells compared with subclinical cows. When infected with live MAP, there was no effect of infection group or parturition on cell subpopulations. In fresh PBMCs, clinical cows expressed lower percentages of CD4(+)CD5(bright) and CD8(+)CD5(bright) compared with control cows, but greater percentages of CD5(dim) cells for all lymphocyte subsets. These results suggest changes in the percentages of lymphocyte subsets, monocytes, and CD5 markers are modulated by both infection status and the periparturient period.     

Altered leukocyte responsiveness in dairy cows with naturally occurring chronic Staphylococcus aureus mastitis

Changes in inflammatory parameters, leukocyte surface markers, functional responses and cytokine mRNA expression of leukocytes of dairy cows with naturally occurring chronic Staphylococcus aureus (S. aureus) mastitis and healthy cows were determined to elucidate the leukocyte responses to S. aureus infection of the mammary gland. Increased values in inflammatory parameters and matrix metalloproteinase activities in milk revealed the characteristics of cows with chronic mastitis. Expression of L-selectin and CD18 molecules on neutrophils and proportion of CD8 cells in milk from cows with S. aureus mastitis were significantly (P<0.05) increased compared with those found in healthy cows. The FcR-stimulated CL response of blood neutrophils was significantly (P<0.05) decreased in cows with S. aureus mastitis. Significantly (P<0.05) decreased mitogenic responses of lymphocytes were found in cows with S. aureus mastitis; however, the values were not restored to those of healthy cows when stimulated with both mitogens and the cytokine IL-1β. The mRNA expression of TNF-α, IL-1β and IL-8 on milk leukocytes from cows with S. aureus was found to be increased compared with that of healthy cows. The changes of immune responses found in cows with S. aureus mastitis appear to be influenced by the severity and duration of inflammation in infected quarters. The down-regulation of the leukocyte functions found in cows with S. aureus mastitis appears to be associated with the progress of the chronic stage of S. aureus mastitis.     

Fertility of dairy cows in Northern Ireland

A comprehensive database was established on the milk production and reproductive performance of dairy cows in 19 selected herds in Northern Ireland, varying in size, management system and genetic merit. Data were obtained for 2471 cows, 1775 of which calved in a second year, and 693 were culled from the herd for specific reasons. The estimated mean rate of heat detection (assessed by the interheat interval during the main breeding season) in all the herds was 71 per cent, with a range from 53 to 92 per cent The average conception rate to first insemination was 37.1 per cent (range 21 to 66 per cent). The average calving interval for the retained cows was 407.2 days (range 359 to 448 days). Twenty-eight per cent of the cows that calved were culled, with infertility being the largest single reason (26.8 per cent of the cows culled). There were major differences in reproductive performance between the herds, but heat detection rate, conception rate and calving interval did not appear to be affeded by a herd's genetic merit. The herds with shorter calving intervals were characterised by better heat detection efficiency (83 v 61 per cent, P<0.01), a shorter interval from calving to first insemination (74 v 97 days; P<0.05), a higher conception rate to first insemination (45 v 34 per cent, P>0.10) and a lower removal rate (23 v 37 per cent, P<0.01). Furthermore, the cows in these herds had lower body condition scores (BCS) in the dry period (3.0 v 3.3; P<0.05) but lost less body condition in early lactation (0.3 v 0.6 BCS units, P<0.05). These results show that dairy herd fertility in Northern Ireland is generally low and similar to that previously reported for England and the USA, but that in some herds changes in herd management practices improved the cows' fertility.