西杂牛产奶性能试验研究

用西门塔尔级进杂交改良本地黄牛,产生西杂一代、二代、三代牛。分别对其1、2、3胎产奶量进行测定,结果表明：各代胎次之间奶量差异不显著（P〉0.05）,但从1胎到3胎上升势头明显,3胎最高;各代305 d平均产奶量差异极显著（P〈0.01）,西杂一代最低、三代最高,产奶天数随着杂交代次提高而逐渐增加;西杂牛产奶收益显著。开展西杂牛挤奶是增加奶源、提高养殖效益的重要举措。     

Variations in the Length of the Y Chromosome and the Seminal Attributes of Karan Fries Bulls

Fresh semen and blood samples from 20 Karan Fries bulls (4–6 years of age), maintained at the Artificial Breeding Complex of the National Dairy Research Institute, Karnal, were collected for one year. All the bulls had 60 chromosomes, comprising 58 acrocentric autosomes and 2 sex chromosomes, with X as the larger and Y as the smaller submetacentric. The mean lengths of Y_p and Y_q; the total length of the Y chromosome and the length ratio were 1.10±0.01 m, 1.83±0.02 m, 2.92±0.02 m and 62.46%±0.18%, respectively. Analysis of the length measurements of the the Y chromosomes in Karan Fries bulls showed that all the measurements, viz., the short arm of the Y chromosome, the long arm of the Y chromosome, the total length of the Y chromosome and the variation in length of Y chromosome, varied significantly among bulls. All the seminal parameters, the volume of semen, mass activity, initial motility, concentration, live sperm count and the total abnormal sperm count, were significantly affected by bulls, whereas season had a significant effect on all the seminal parameters except the total abnormal sperm count. No significant relationship between the ratio of the long arm to the total length of the Y chromosome and seminal attributes was observed.     

Genetic relationships of fertility traits with test‐day milk yield and fat‐to‐protein ratio in tropical smallholder dairy farms

The test‐day milk fat‐to‐protein ratio (TD‐FPR) could serve as a measure of energy balance status and might be used as a criterion to improve metabolic stability and fertility through genetic selection. Therefore, genetic parameters for fertility traits, test‐day milk yield (TD‐MY) and TD‐FPR, as well as, their relationships during different stages of lactation, were estimated on data collected from 25 968 primiparous Thai dairy crossbred cows. Gibbs sampling algorithms were implemented to obtain (co)variance components using both univariate linear and threshold animal models and bivariate linear‐linear and linear‐threshold animal models with random regression. Average TD‐MY and TD‐FPR were 12.60 and 1.15. Heritability estimates for TD‐MY, TD‐FPR and selected fertility traits ranged from 0.31 to 0.58, 0.17 to 0.19 and 0.02 to 0.05, respectively. Genetic correlations among TD‐FPR and TD‐MY, TD‐FPR and fertility traits, and TD‐MY and fertility traits ranged from 0.05 to ‐0.44, from ‐0.98 to 0.98 and ‐0.22 to 0.79, respectively. Selection for lower TD‐FPR would decrease numbers of inseminations per conception and increase conception at first service and pregnancy within 90 days. In addition, cow selection based only on high milk production has strong effects to prolong days to first service, days open and calving interval.     

杂交猪繁殖性能的影响因素分析

本研究利用SPSS软件中的方差分析等模块分析了年份、季节、胎次、性别和杂交方式等因素对杂交猪繁殖性能的影响。结果表明,年份对产活仔数和断奶仔猪数有极显著影响(P＜0.01),而对总产仔数无显著影响(P＞0.05)。季节对产活仔数和断奶仔猪数有极显著影响(P＜0.01),对总产仔数有显著影响(P＜0.05)。胎次对断奶仔猪数和初生重有极显著影响(P＜0.01),对产活仔数和出生窝重有显著影响(P＜0.05)。公猪的初生重显著大于母猪的初生重(P＜0.05)。杂交方式对总产仔数、产活仔数、断奶仔猪数、出生窝重和初生重均无显著影响(P＞0.05)。     

利用皮特兰作父系商品猪肉品质的灰色关联度分析

运用灰色关联度法对含皮特兰血的4个组合杂交猪（皮杜、皮杜B、皮杜大、皮杜长大）的瘦肉率、熟肉率、大理石纹评分、肉色评分、pH值、失水率和嫩度等7个肉质指标按等权关联度进行了综合评定,以评价皮特兰在商品猪生产中的种用价值。结果表明：“皮杜B”肉质最优,其次是“杜长大”和“皮杜长大”,说明以提高瘦肉率为目标利用“皮杜”公猪,“皮杜长大”4系配套组合和“皮杜”公猪与培育品种杂交肉质最佳。     

杂交茄子新品种“呼茄7号”的选育

呼茄7号是以9102—1—3—8为母本,79801—2—2—2为父本配制的一代杂种。该品种中晚熟,始花节位8-9节。果实近圆形,果皮黑紫色,光泽度强,耐弱光,耐老化,果肉较紧实。平均单果重量450g左右,露地每667m^2产量4800kg左右。适宜露地及保护地栽培。     

Genetic parameters and purebred–crossbred genetic correlations for growth,meat quality,and carcass traits in pigs

Growth, meat quality, and carcass traits are of economic importance in swine breeding. Understanding their genetic basis in purebred (PB) and commercial crossbred (CB) pigs is necessary for a successful breeding program because, although the breeding goal is to improve CB performance, phenotype collection and selection are usually carried out in PB populations housed in biosecure nucleus herds. Thus, the selection is indirect, and the accuracy of selection depends on the genetic correlation between PB and CB performance (rpc). The objectives of this study were to 1) estimate genetic parameters for growth, meat quality, and carcass traits in a PB sire line and related commercial CB pigs and 2) estimate the corresponding genetic correlations between purebred and crossbred performance (rpc). Both objectives were investigated by using pedigree information only (PBLUP) and by combining pedigree and genomic information in a single-step genomic BLUP (ssGBLUP) procedure. Growth rate showed moderate estimates of heritability for both PB and CB based on PBLUP, while estimates were higher in CB based on ssGBLUP. Heritability estimates for meat quality traits were diverse and slightly different based on PB and CB data with both methods. Carcass traits had higher heritability estimates based on PB compared with CB data based on PBLUP and slightly higher estimates for CB data based on ssGBLUP. A wide range of estimates of genetic correlations were obtained among traits within the PB and CB data. In the PB population, estimates of heritabilities and genetic correlations were similar based on PBLUP and ssGBLUP for all traits, while based on the CB data, ssGBLUP resulted in different estimates of genetic parameters with lower SEs. With some exceptions, estimates of rpc were moderate to high. The SE on the rpc estimates was generally large when based on PBLUP due to limited sample size, especially for CBs. In contrast, estimates of rpc based on ssGBLUP were not only more precise but also more consistent among pairs of traits, considering their genetic correlations within the PB and CB data. The wide range of estimates of rpc (less than 0.70 for 7 out of 13 traits) indicates that the use of CB phenotypes recorded on commercial farms, along with genomic information, for selection in the PB population has potential to increase the genetic progress of CB performance.     

不同赖氨酸水平的低蛋白质饲粮对70－125 kg二元母猪生长性能、血清指标的影响

本试验选用96头体况相似、平均体重为69.01±4.43 kg的长大二元母猪,随机分成4个组,每个组4个重复。根据饲料原料可消化赖氨酸(DLys)和理想蛋白质氨基酸平衡模式(IAAP)配制低蛋白质试验饲粮(等能、等氨基酸平衡模式),测定不同饲粮赖氨酸水平对70－100 kg阶段和100－125 kg阶段二元母猪生长性能、血清指标的影响。结果表明,70－100 kg阶段,2组平均日增重(ADG)最高(908.33 g),料重比(F/G)最低(2.77)；2组血清尿素氮(UN)浓度显著低于1组和4组(P<0.05),与3组差异不显著(P>0.05),血清胰岛素(INS)、类胰岛素生长因子－Ⅰ(IGF-Ⅰ)浓度呈现随饲粮DLys水平的升高先升高后降低的变化趋势(P>0.05)；血清赖氨酸(Lys)和苏氨酸(Thr)浓度4组显著高于1组(P<0.05),其它血清氨基酸浓度呈现随饲粮DLys水平的升高先降低后升高的变化趋势(P>0.05),以2组较低。100－125 kg阶段,2组ADG最高(863.14 g),F/G 2组最低(3.08)；血清UN浓度3组显著低于1组和4组(P<0.05),与2组间差异不显著(P>0.05),血清INS浓度3组显著高于1组(P<0.05),与2组和4组间差异不显著(P>0.05)；血清IGF-Ⅰ浓度呈现随饲粮DLys水平的升高先升高后降低的变化趋势(P>0.05)；血清Lys浓度1、2组显著低于3、4组(P<0.05),其它组血清氨基酸浓度基本呈现随着饲粮DLys水平的升高先降低后升高的变化趋势(P>0.05),以2组较低。因此,在本试验条件下,二元母猪70－100 kg阶段和100－125 kg阶段饲粮DLys适宜日摄入量分别为16.57 g/d和15.96 g/d,即饲粮赖氨酸水平分别为0.66%和0.60%,能获得较好的生长性能。     

西藏工布江达县牦牛、黄牛、甲咂牛红细胞数及其直径研究

首次报道了西藏高原海拔3600m、雅鲁藏布江河谷工布江达县生态环境下的牦牛、黄牛、甲咂牛红细胞数、直径及其大小比例。含印度瘤牛血的甲咂牛红细胞总数,明显高于牦牛和黄牛。红细胞平均直径,牦牛为5.68μm,黄牛为5.75μm,甲咂牛为5.54μm,种内差异不显著,但这两种牛与甲咂牛之间差异极显著。