夏洛来母牛生殖性能及利用年限观察

对法系纯繁夏洛来母牛生殖性能的统计表明:初情期平均13.0±1.89月龄,性成熟期平均14.62±2.6月龄,始配年龄21.56±1.23月龄,绝情期15岁左右;发情周期平均20.51±8.49d,卵泡出现至排卵结束约39.26±8.28h;妊娠期平均283.91±8.05d;犊牛初生重43.49±6.85kg;产后发情平均71.18±49.25d;产犊间隔平均452.26±124.59d。母牛淘汰年龄平均94.77±40.84月龄,利用年限平均69.94±40.66月龄,终生产犊4.78±2.95头。     

夏洛来母牛生殖性能及利用观察

对法系纯繁夏洛来母牛生殖性能的统计表明:初情期平均12.94月±1.89月龄,性成熟期平均14.62月±2.6月龄,始配年龄21.65月±1.23月龄,绝情期15岁左右;发情周期平均20.51天±8.49天,卵泡出现至排卵结束约39.26小时±8.28小时;妊娠期平均283.91天±8.05天;犊牛初生重43.49kg±6.85kg;产后发情平均71.18天±49.25天;产犊间隔平均452.26天±124.59天。母牛淘汰年龄平均94.77月±40.84月龄,利用年限平均69.94月±40.66月龄,终生产犊4.78头±2.95头。     

西门塔尔牛改良延边本地黄牛效果分析

为了研究西门塔尔牛对本地黄牛的改良效果。利用西门塔尔牛冻精为本地黄母牛人工授精,测定了3日龄、6月龄和12月龄西本F1公、母牛的体尺、体重、并与相应年龄性别的本地黄牛进行比较。结果发现：西本F1公、母牛各项指标均显著或极显著地高于本地黄牛,表明利用西门塔尔牛冻精杂交改良本地延边黄牛是切实可行的。     

利用西门塔尔牛杂交改良本地黄牛效果观察

为了研究西门塔尔牛对本地黄牛的改良效果,利用西门塔尔牛冻精为本地黄母牛人工授精,测定了初生、6月龄和12月龄西本F1公、母牛的体尺、体重、并与相应年龄性别的本地黄牛进行比较。结果发现:西本F1公、母牛各项指标均显著或极显著地高于本地黄牛,表明利用西门塔尔牛冻精杂交改良本地黄牛是切实可行的。     

甘肃陇南本地黄牛与西门塔尔牛杂交效果研究报告

本试验利用西门塔尔种公牛冻精为甘肃省陇南地区本地黄牛进行人工授精,测量了初生、6月龄和12月龄西本F1公、母牛的体尺、体重,并与相应年龄性别的本地黄牛进行比较分析。结果显示:西本F1公、母牛测定指标均显著或极显著地高于本地黄牛,说明利用西门塔尔牛的合格冻精改良陇南本地黄牛切实可行,具有一定的杂交改良效果。     

西门塔尔牛改良甘肃河西地区本地黄牛效果调查

为了研究西门塔尔牛对本地黄牛的改良效果,利用西门塔尔牛冻精为甘肃省河西地区黄牛人工授精,测定了初生、6月龄和12月龄西本F1公、母牛的体尺、体重,并与相应年龄性别的本地黄牛进行比较。结果显示:西本F1公、母牛各项指标均显著或极显著地高于本地黄牛(P<0.05)。表明利用西门塔尔牛冻精杂交改良本地黄牛是切实可行的,具有很好的改良效果。     

美系短角牛犊牛培育的综合措施

短角牛是世界著名而古老的牛品种之一,云南省于1996年12月从美国引入肉用型种牛106头(公牛14头,母牛92头),通过在中华人民共和国第五动物隔离检疫场60 d的隔离检疫后,于1997年1月在云南省种羊场肉牛纯繁场进行驯化饲养.目前存栏310头,其中能繁母牛152头,后备母牛46头,断奶母犊52头,成年公牛13头,后备公牛8头,断奶公犊39头.     

浙江温岭高峰牛繁殖性能的探讨

<正> 温岭高峰牛属亚热带瘤型牛,是经过长 期的精心管养,选育和提纯复壮而成。具有性成熟早,生长发育快,繁殖力强,遗传性稳定等优良特性。据我们多年的调查和试验观察,温岭高峰牛的繁殖率较高,约相当于全国水平的2倍(全国一般只有40～50％)。据1980年调查,182头可繁母牛,年内产犊149头,产犊率达81.9％;1981年3月调查了151头可繁母牛,怀胎137头,带犊34头,其中带犊怀胎20头,受胎率达97.7％;又据1981年底普查,193头能繁母牛,年内产犊183头,产犊率达94.8％,受胎189头,受胎率达97.9％,年内出售6月龄的犊牛181头,纯繁率达93.8％。     

弗莱维赫牛改良西杂牛生长性能的对比试验

1材料与方法1.1试验牛的选择与分组在规模养牛户中选择母牛年龄、胎次和膘情相接近,饲养管理条件基本相同的经产本地西杂牛600头,随机分为2组,每组300头,1组用弗莱维赫牛冻精授配,即弗莱维赫(♂)×本地西杂(♀)杂交组合为实验组;另1组采用西门塔尔牛级进杂交本地西杂牛(对照组)。产犊后,2组均以出生为顺序,选公、母犊各40头作为出生6月龄、12月龄、18月龄     

张掖肉牛世代选育繁殖性能研究

【目的】研究张掖近20年来选育的肉牛新品种各世代公、母牛繁殖性能,为种群扩繁和高效推广利用提供科学依据。【方法】利用张掖肉牛新品种选育技术资料,对4个世代的选育张掖肉牛配种、产犊记录进行分类汇总、统计分析,数据用Excel 2010进行初步整理。【结果】张掖肉牛母牛初配年龄为 15～18月龄, 初配体重为380～420公斤, 产犊月龄为 21～24月龄。横交选育的不同世代母牛表现出较好的繁殖性能, 平均犊牛成活率 97.9 %, 繁殖成活率 81.74 %。     

凉州区肉牛繁殖技术试验示范与推广研究

[目的]为筛选出适合凉州区肉牛繁殖的新模式。[方法]选择夏洛莱（XL）、利木辛（LM）、安格斯（AG）成年种公牛生产冻精,在西门塔尔和本地黄牛杂交一代（西本F1）成年母牛上实施人工授精,对杂交犊牛分月龄进行外貌体尺测定。[结果]XL冻精与西本F1代的后代体重、体高、体斜长、胸围、管围等生长指标均高于LM和AG后代指标。试验2方法是选择XL、LM、AG成年母牛生产冻胚,在成年母牛上实施胚胎移植,犊牛出生后进行外貌体尺测定。结果是：夏洛莱胚胎移植后代牛初生重、6月龄、12月龄体重、体高、体斜长、胸围、管围均高于利木辛与安格斯牛杂交后代（P〈0.01）。试验3方法是选择西杂F1和F2代母牛,用引进的XM（西门塔尔）牛X性控冻精实施人工授精,犊牛出生后统计相关数据。结果是：三组共授配母牛138头,情期妊娠75头,情期平均受胎率为54.1%,平均母犊率为90.3%。[结论]夏洛莱品种改良西杂一代牛后代生长发育比其余品种好;实施胚胎移植后,夏洛莱品种胚胎移植后代牛比其余品种在凉州区生长适应性强,适宜在该环境条件下生长;西门塔尔牛性控冻精的配种试验是成功的,是生产母犊的较好方法。     

Antibodies to bovine leukemia virus in a leukosis dairy herd and suggestions for control of the infection.

A closed herd of 765 Holstein-Friesian dairy cattle with a history of multiple cases of leukosis was tested for antibodies to bovine leukemia virus by the bovine leukemia-glycoprotein immunodiffusion test. A total of 355 animals (46.4%) were antibody positive. Prevalence was 60% in the 373 milking cows and 100% in the breeding bulls. Antibodies were present in 59% of newborn calves. Prevalence of antibodies was higher in older animals and cows in second lactation had a higher prevalence than cows in first lactation (72% vs 43%). Proposed control measures in this herd aim at preventing infection of calves, heifers and lactating cows by: 1) separating them into groups negative and positive for bovine leukemia virus antibodies, 2) not allowing calves to receive colstrum or milk from infected cows and 3) by using seronegative bulls for natural breeding tested at three month intervals. Calves should be tested after six months of age. Before this time calves of positive mothers should be treated as being positive.     

德国弗莱维赫(Fleckvieh)牛和本地牛杂交F1代母牛生长发育性状测定及分析

[目的]为了研究德国弗莱维赫(Fleckvieh)牛与本地母牛杂交F_1代育成母牛生长发育性状和生长发育规律,为培育北大荒乳肉兼用牛品种,开展选育提高奠定基础。[方法]采用各批次测定体重校正到统一月龄,测定了其初生、4月龄(断奶)、12月龄及18月龄4个阶段的体重、体尺,并对各阶段表型值比较分析。[结果]德国弗莱维赫(Fleckvieh)牛与本地母牛杂交F_1代母牛平均日增重、胸围和体斜长性状,在初生至4月龄断奶阶段生长发育最快;从4月龄断奶至18月龄,与纯种德国弗莱维赫种公牛与澳系(澳大利亚)西门塔尔母牛杂交后代相比,在体重和体尺上有一定差异。[结论]需要不断地改良,以提高后代的生长发育性状,进一步提高生产性能。     

Heifer rearing conditions affect length of productive life in Swedish dairy cows

Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The applied Weibull proportional hazards model included time-independent effects of breed, housing from 3 to 7 months of age, number of housing changes before calving, grazing before 1st calving, herd median age at 1st calving, age at 1st calving, cow housing, herd lactational incidence risk of veterinary-reported clinical mastitis, and the random effect of herd. Time-dependent effects were year, month, the interaction year by month, parity, number of breedings, pregnancy status, the interaction parity by pregnancy status, herd mean milk-production level, relative milk yield within breed-parity, and veterinary-reported clinical mastitis. The lactation was divided into six stages in which pregnancy status was assumed to be known by the farmer and culling could occur. Median productive life time in culled cows was 780 d and 14% of the records were censored due to terminated data collection. An individual calving age of 28.2–30.9 months was associated with the highest culling risk, 1.2-fold higher than calving at ≤25.3 months, whereas the risk decreased almost linearly with a higher herd median age at 1st calving. Housing in slatted pens with >7 calves from 3 to 7 months was associated with a 1.7-fold increase in risk, relative to litter pens. If a cow had changed housing system 4 times before 1st calving it increased the risk of culling 1.4 times, relative to two housing changes. These results show that rearing factors affect the productive life time of dairy cows in Swedish family operations.     

BREEDING FOR RESISTANCE TO BOOPHILUS MICROPLUS IN AUSTRALIAN ILLAWARRA SHORTHORN AND BRAHMAN X AUSTRALIAN ILLAWARRA SHORTHORN CATTLE

SUMMARY Breeding for resistance to the cattle tick Boophilus microplus was undertaken in a herd of Australian Illawarra Shorthorn (AIS) cattle from 1961 to 1978 and in a herd of Braham x AIS cattle from 1970 to 1979. Breeder cows and their progeny were assessed for tick resistance during October to January. Resistance levels were determined as the average percentage mortality of female ticks from two artificial infestations with cohorts of c 20,000 larvae. Resistance increased from 89.2% to 99% in the AIS breeding herd, as a result of the yearly introductions of more resistant individuals and culling of less resistant ones. Concurrently resistance in the AIS progeny increased from 93.7% to 97.7%, thus demonstrating that the selection and breeding of the cows and bulls resulted in genetic improvement in the resistance of the progeny. Milk production tests on heifers from the selected AIS herd during 1975 to 79 indicated that selection for tick resistance did not select against milk production. Resistance of the Brahman x AIS increased from 98.4% to 99.3% in the breeding herd and from 97.6% to 99.6% in the progeny. Female calves of both breeds were more resistant than males.     

夏洛来公牛繁殖性能及利用年限观察

对夏洛来公牛繁殖性能的分析表明：初采精以２０月龄为宜。采精利用以３～５岁龄精液产量、质量最好,６岁后呈下降趋势。一年中春季精液量多质佳,冬季次之,夏秋二季较差。公牛淘汰年龄９３．４月龄,利用年限７０．１月龄。终生均产冻精８９０００余粒。制约繁殖性能的因素包括：年龄、季节、热应激、疾病等。     

Effects of crossbreed pregnancies on the abortion risk of Neospora caninum-infected dairy cows

Previous studies have shown that the use of beef bull semen significantly reduces the rate of abortions due to Neospora caninum in artificially inseminated (AI) seropositive dairy cows. In addition, certain beef breeds could be more resistant to N. caninum infection and abortion than others. The aim of the present study was to determine whether different crossbreed pregnancies, those derived from Limousin, Charolais, Piedmontese or Belgian Blue semen, carry different risks of abortion in Neospora-infected dairy cows. The effects of possible interactions between maternal levels of N. caninum antibodies and the different breed crosses were also evaluated. The study was performed on five commercial Holstein–Friesian dairy herds in Northeast Spain with previously confirmed diagnoses of N. caninum infection in aborted foetuses. The study population was comprised of 1115 pregnancies: 633 pregnancies recorded after AI using Holstein–Friesian semen from 18 bulls and 482 after AI using beef semen from 27 bulls (304 inseminations using semen from Limousin bulls, 191 from Belgian Blue bulls, 89 from Piedmontese bulls and 49 from Charolais bulls). Abortion rates were 32.2% (155/482) and 15.2% (96/633) for seropositive cows inseminated with Holstein–Friesian and beef breed semen, respectively. Logistic regression analysis revealed the herd and the interaction between maternal N. caninum antibody titre and the different crossbreeds as significant factors affecting the abortion rate. Lowest abortion rates, similar to that shown by seronegative animals in the analysed herds (3.2%, 239/7432), were observed in dams AI using Limousin semen that had low (<30 relative index (RI) units) N. caninum antibody titres (2.1% abortion, 3/145) and these cows were used as reference. Compared to the cows used as reference, cows with low N. caninum antibody titres (<30 RI units) showed a similar risk of abortion when inseminated with Piedmontese or Charolais bull semen, but higher risk of abortion when inseminated with Holstein (17.9 times) or Belgian Blue (7.2 times) bull semen. All cows with high N. caninum antibody titres (≥30 RI units) had a higher risk of abortion, ranging from 8.9 times (cows inseminated with Limousine semen) to 37.8 times (cows inseminated with Piedmontese semen), compared to the cows used as reference. In conclusion, different crossbreed pregnancies carried different abortion risks in Neospora-infected dairy cows. The use of beef bull semen dramatically reduced the risk of abortion in dairy cows, especially if Limousin breed semen was used. Moreover, this reduction was found to be dependent on the N. caninum antibody titre such that the lowest incidence of abortions was recorded in Limousin semen inseminated cows with low antibody titres. Insemination of Neospora-seropositive cows with beef bull semen could both reduce the risk of abortion and avoid breeding replacements for infected cattle.     

蒙贝利亚牛与荷斯坦牛在北方地区生长发育差异性比较

本研究对11头蒙贝利亚母牛和9头蒙贝利亚公牛的生长发育进行了跟踪测定,并与同期荷斯坦母牛的生长发育、产奶性能进行了对比分析。结果表明,蒙贝利亚母牛与荷斯坦母牛初生重无显著差异;4～18月龄,蒙贝利亚母牛体重均明显高于荷斯坦母牛同期体重,差异极显著（P〈0．01）。蒙贝利亚母牛与荷斯坦母牛日增重变化规律相似,lOB龄平均日增重最大,17月龄平均日增重最小。蒙贝利亚母牛各阶段体高、体长与荷斯坦母牛无显著差异,14月龄体高可达127cm,达到配种体高。蒙贝利亚母牛头胎305d产奶量为7241kg,对照组荷斯坦母牛头胎305d产奶量为9589kg,二者差异极显著（P〈0．01）。蒙贝利亚公牛初生重较大,至24月龄体重接近荷斯坦公牛同期体重。12~24月龄,荷斯坦公牛体高、体斜长、胸围均明显高于蒙贝利亚公牛,差异板显著（P〈0．01）;蒙贝利亚公牛初生重48kg,蒙贝利亚母牛初生重42kg,二者差异显著（P〈0．05）。蒙贝利亚公牛各阶段睾丸周径均显著高于荷斯坦公牛,差异极显著（P〈0．01）。     

夏南正回交后代、反回交后代及南阳牛的体重、体尺对比研究——河南省泌阳县"南阳牛导入夏洛来杂交育种"项目技术报告(二报)

本研究把夏南杂交的正回交后代、反回交后代及南阳牛的体重、体尺作了比较分析。结果表明，初生、6、12、18及24月龄，正、反回交后代公、母牛平均体重均高于同龄同性别南阳牛，差异均极显著，正回交公牛与反回交公牛相比，平均初生重差异不显著；6、12、18月龄反回交公牛平均体重明显高于正回交公牛，差异均极显著，24月平均体重差异不显著；正回交母牛与反回交母牛相比，反回交母牛平均初生体重高于正回交母,两者差异显著，但6、12、18及24月龄平均体重差异不显著。     

Reproductive Performance and Reconception of Nellore Cows According to Their Pure‐ or Cross‐Bred Calves

The objective of the present research was to evaluate the effect of a calf's genetic group on the productive and reproductive efficiency of its Nellore dam. Fixed‐time artificial insemination was applied to 800 cows using semen extracted from Nellore, Simmental and Angus Red bulls. Four hundred eleven cows calved, producing 119 Nellore, 103 ½Simmental–½Nellore and 189 ½Nellore–½Angus Red calves. The second mating period, which paired Nellore cows with Simmental bulls, was initiated 10 days after parturitions began and lasted for 5 months. Based on the two successive parturitions, the cumulative parturition rate for calving periods of 3, 4 and 5 months was calculated. Although no significant difference was observed for birth weight among the genetic groups, cross‐bred calves weighed, on average, 10% more than did pure‐bred calves at the age of 205 days. Nellore dams experienced a gestation period that was 7 days longer than did the cross‐bred dams, and the former showed a higher parturition rate at 90 and 120 days of the calving season, but not at 150 days (calving rates of 80.6, 76.4 and 76.2% for mothers of Nellore, ½Nellore–½Angus Red and ½Nellore–½Simmental, respectively, p > 0.05). At 90 and 120 days, Nellore dams produced more kg of calf per mated dam. In conclusion, in a short breeding season, Nellore dams nursing pure‐bred Nellore calves were found to have a higher biological efficiency compared with Nellore dams nursing cross‐bred calves.