波尔山羊与睢宁白山羊杂交羔羊生长性能研究

研究波尔山羊与睢宁白山羊F1 代、F2 代的生长发育情况 ,结果从出生到 3个月不同日龄羔羊的体重体尺均高于纯种睢宁白山羊 ,杂交优势显著 ,F1 代体重的杂种优势率为 18 96 % ,杂种后代生长性能比睢宁白山羊好     

肉用西门塔尔牛改良云南黄牛的效果初报

对云南黄牛、西门塔尔与云南黄牛的杂交牛（西本杂）体尺体重进行了测定,结果西本牛与本地牛体尺体重都有了显著提高（P＜0．01）。西本杂牛的初生、6、12、18、24月龄体重比同龄本地牛分别高出82％、18％、69％、50％、78％。     

The Effects of Trypanosomosis on Sperm Morphology in Zebu×Friesian Crossbred Bulls

Detailed studies of sperm morphological abnormalities were carried out on 12 Zebu x Friesian crossbred bulls used in a study of the effects of trypanosomosis. Four bulls were infected with T. vivax, another four with T. congolense, while four served as controls. The infected bulls developed chronic trypanosomosis. All the bulls initially had very low sperm morphological abnormalities that were within acceptable limits for fertile animals. After infection there was a rapid and progressive increase in all sperm abnormalities. Spermatozoa of infected bulls were highly deformed with multiple morphological defects. Mean percentage pre-infection baseline values prior to infection for acrosomal, sperm-head, detached heads, proximal cytoplasmic droplets, distal cytoplasmic droplets, sperm-tail, midpiece and total sperm morphological defects ranged between 0.1 +/- 0.1 for acrosomal and 8.3 +/- 3.2 for total morphological abnormalities in the semen of the bulls. All the infected bulls developed sperm morphological abnormalities of more than a mean of 40.0% from the 4th week after infection until the end of the investigation and were considered unfit for breeding. At 7 weeks post-infection (PI) until the end of the study (12 weeks PI), the controls had a mean of less than 5% sperm morphological defects, while the infected bulls had 100%. Mean percentage values of sperm morphological defects throughout the duration of the investigation for control bulls were low and within the normal range for fertile bulls. These values differed significantly (p<0.001) from the elevated values of the infected bulls. The results show that trypanosomosis due to T. vivax or T. congolense infection can render Zebu x Friesian crossbred bulls unfit for breeding within a very short time. The resultant infertility could be of economic importance in trypanosomosis-endemic sub-Saharan Africa where Zebu x Friesian crossbred bulls are kept.     

Factors Affecting Fertility According to the Postpartum Period in Crossbred Dual-Purpose Suckling Cows in the Tropics

To determine the relationship between first service conception rate (FSC) and the postpartum period (PP), 6160 calvings from 2250 crossbred dual-purpose cows were analysed. The effects of breed predominance (BT: Bos taurus and BI: Bos indicus), season of service (dry, intermediate and humid), parity (1 or 2 and more), agroecological region (Sub-humid and Dry Tropical Forest) and milk production were studied. The postpartum period was grouped according to the calving–first service interval as G1 ≤ 60 days (n = 1889); G2 > 60 ≤ 90 days (n = 1436); G3 > 90 ≤ 120 days (n = 1030); and G4 > 120 days (n = 1805). Data were analysed by chi-squared test. The overall mean for FSC was 58.2% and was lower in G1 (p < 0.01). All PP showed a breed effect on FSC, with mean values of 61.6% and 53.3% for BI and BT, respectively. Season of service also affected FSC, which was significantly lower during the humid period: 51.2% versus 57.4% and 61.5% for the intermediate and dry periods (p < 0.01), respectively. Parity and environmental effects were not observed on FSC. Levels of milk yield did influence the FSC, which decreased from 66.7% and 61.0% for milk yields of < 1500 kg and between 1501 and 2000 kg to 46.0% in milk yields > 2000 kg (p < 0.01).     

Reproductive Disorders of Crossbred Dairy Cows in the Central Highlands of Ethiopia and Their Effect on Reproductive Performance

The study was conducted to estimate the proportion of reproductive disorders and to determine factors affecting reproductive performance of crossbred dairy cows under four different production systems in the central highlands of Ethiopia. The principal postpartum reproductive disorders were retained fetal membranes (14.7%) and uterine infection (15.5%). Anoestrus was the major postpartum reproductive problem in the mixed crop–livestock production system (38.6%) and was significantly associated with this production system. Apart from anoestrus, the occurrence of reproductive disorders was not significantly associated with a production system. Most of the reproductive disorders occurred as a complex rather than as a single abnormality. Two or more abnormal conditions were seen in 11.4% of the cases. Each reproductive trait measured was affected adversely by reproductive disorders. Cows with reproductive disorders in each production system, lactation group and suckling and non-suckling group had longer intervals from calving to first service and to conception (p < 0.001) and required more services per conception (p < 0.001). Pregnancy rate and conception to first service were 84.7% and 51.7%, respectively, for cows without reproductive health problems; and 64.2% and 15.1%, respectively, for cows with reproductive disorders (p < 0.001). Overall, intervals from calving to first service were shorter (p < 0.05) than in younger cows. Intervals from calving to first service and to conception were longer in suckling than in non-suckling cows (p > 0.05). Cows with a good body condition score (>3.5) at calving had shorter calving to first service and conception intervals than cows in poor condition (p < 0.001). The results showed that reproductive abnormalities, coupled with poor body condition, are important factors that contributed to reproductive inefficiency. An appropriate reproductive health management, a reliable artificial insemination service and supplementary feeding could be the management options to reduce or alleviate some of the problems.     

娟姗牛与西杂牛杂交后代生长发育观测

[目的]旨在繁育适于牦牛杂交改良的乳肉兼用父本.[方法]在海拔相对较低的半农半牧区,用娟姗牛与西杂牛杂交,观察杂交后代的生长发育和配种情况.[结果]娟姗牛与西杂牛的杂交后代在甘南州高海拔地区具有较好的适应性,表现出明显的杂交优势,能与甘南牦牛自然交配.     

杜蒙杂交母羊的繁殖规律研究

旨在研究杜蒙杂交母羊的繁殖规律。对内蒙古自治区乌兰察布市四子王旗范围内养殖的杜蒙杂交母羊（n=668）的首次发情时间、妊娠期、产羔率、产双羔率等指标数据进行整理;采用公羊试情方法,观察并记录杜蒙杂交母羊（n=302）的发情周期和发情持续时间。对上述指标数据进行分析,探究该地区杜蒙杂交母羊的繁殖规律。结果表明：杜蒙杂交母羊平均首次发情时间为8.5月龄（最早7.0月龄、最晚10.7月龄）,平均发情周期为16.0 d（最短13.5 d、最长18.5 d）,平均发情持续时间为24.0 h（最短20.0 h、最长27.5 h）,平均妊娠期为146.0 d（最短143.0 d、最长149.0 d）,产羔率为119.7%,产双羔率为19.7%。研究结果为掌握杜蒙杂交母羊自然发情规律,以及准确把握最佳配种时间提供了依据。     

后非洲猪瘟时期洋三元（DLY）商品母猪作种用的可行性分析及建议

自从2018年非洲猪瘟在中国暴发以来,为了尽快恢复产能,我国很多猪场在生产上开始采用洋三元商品母猪留作种用。通过收集某大型猪场的二元（（LY）母猪和洋三元（DLY）商品母猪的生产记录,统计两者在生产成绩上的差异,并综合其他文献来分析洋三元商品母猪留作种用的优缺点,给出改进的措施,为后非洲猪瘟时期养猪生产提供参考。     

饲喂代乳料对早期断奶羔羊生长发育的影响

选择36只25日龄的欧拉藏羊与小尾寒羊杂交羔羊,随机分为3组,进行早期断奶试验。2个试验组分别饲喂不同配方的代乳料,对照组自然哺乳。结果表明,(1)30～45日龄,试验组羔羊生长速度低于对照组;45～60日龄,试验组羔羊的日增质量显著高于对照组;60～90日龄,试验组羔羊的日增质量极显著高于对照组(P<0.01)。在整个试验阶段,试验1组和试验2组的日增质量分别比对照组提高了52.82%和59.52%,差异显著(P<0.05)。(2)试验期内,试验组羔羊主要体尺略高于对照组,差异不显著。(3)试验组羔羊成活率达到95%以上,断奶母羊提前发情10 d左右。(4)试验1,2组羔羊断奶时每只均利润比对照组分别提高41.15%,45.31%,差异显著(P<0.05)。     

Influence of feeding Tinospora cordifolia peripartum on lactation parameters in crossbred cows

For studying the effect of dietary supplementation of guduchi (Tinospora cordifolia) peripartum on lactation an investigation was conducted on 15 pregnant Karan Fries crossbred cows which were divided into two groups: treatment group of eight cows which were supplemented with guduchi at 60 g/day for 45 days prepartum and 120 g/day for 45 days postpartum; control group of seven pregnant cows which were not supplemented with guduchi. Jugular blood samples were collected from all cows during the periparturient period for analysis of various blood cell and plasma parameters. A significantly higher total leukocyte count, lymphocyte count, neutrophil count and neutrophil/lymphocyte ratio was recorded in the guduchi supplemented treatment group in comparison to untreated control cows throughout the experimental period. The increase of milk production over 305 days of lactation due to guduchi supplementation was significant (p < 0.05). A significant (p < 0.05) reduction in somatic cell count was also observed during the experimental period. Milk composition (fat, protein, lactose and SNF) was similar (p > 0.05) for both the groups. Plasma non esterified fatty acid (NEFA) concentrations were significantly higher (p < 0.01) in cows supplemented with guduchi throughout the course of study. Plasma concentration of growth hormone in the treated cows was also significantly higher beginning on the day of parturition up to 3 weeks postpartum (p < 0.05) in comparison to unsupplemented group.