烤烟青贮饲料饲喂哺乳母猪试验效果的研究

试验选用第二胎基础母猪３０头，按产期和体重相近原则随机等量分为３组，每组１０头。对照组母猪哺乳期喂基础饲料，试验１组用１０％的烤烟青贮饲料代替精料，试验２组与试验１组营养水平基本相同，烤烟青贮饲料喂量为２０％。试验结果表明：各组仔猪２０日龄窝重、３５日龄窝重及哺乳期仔猪成活率等均无显著差异（Ｐ＞００５）；母猪泌乳失重各组差异不显著（Ｐ＞００５）。以试验１组饲料报酬较高，断奶窝重较大，表明在哺乳期母猪饲料中添加１０％的烤烟青贮饲料是可行的。     

仔猪21日龄与28日龄断乳的研究

采用“同窝分组”法，在相同饲养条件下对１０窝１１０头仔猪进行了２１日龄断乳（１组）和２８日龄断乳（Ⅱ组）对比试验，测其各阶段发育，饲料利用率及效益，其结果：Ｉ组仔猪断乳后一周（２８日龄）体重（５．８５千克）和日增重（１７６克），分别比Ⅱ组低２２％和９２％，未增重者占１６．６％，减重者占３６．６％。Ⅱ组仔猪断乳后一周（３５日龄）未增和减重者各占６．７％。４２日龄时两组体重已很接近（Ｐ＞０．０５）。仔猪２１—４２日龄期间各用采食量：Ｉ组分别为０．７６、２．１５和３．７２千克，Ⅱ组分别为０．３２、１．２０和３．１９千克，仔猪在断乳后第２、３周来食量Ⅰ组明显高于Ⅱ组，表明Ⅰ组已进入生长补偿期。４２日．龄左右两组仔猪体重和采食量已无明显差异（Ｐ＞０．０５）。７—６０日龄采食量，Ｉ、Ⅱ组分别为２３．６和２２．２千克（Ｐ＞０．０５）。饲料转化比分别为１．３３和１．１９（Ｐ＞０．０５）。但每头仔猪饲料总成本，Ｉ组比Ⅱ组降低７％。     

乳泉Ⅰ号添加剂提高母猪哺乳性能的研究

选用８６头哺乳母猪，随机分为２组，对照组喂基础日粮，试验组于产后１０日内在基础日粮中添加２．５％的中药复合添加剂（乳泉Ⅰ号）。结果表明，试验组仔猪２０日龄窝重和３５日龄断奶窝重分别较对照组提高２５．５９％和２５．９０％（Ｐ＜０．０１）；仔猪断奶个体重提高１８．５６％（Ｐ＜０．０１）；哺乳期平均日增重提高２２．７６％（Ｐ＜０．０１），哺乳期仔猪成活率提高８．０％（Ｐ＜０．０１）。     

乳泉I号添加剂提高母猪哺乳性能的研究

选用８６头哺乳母猪，随机分为２组，对照组喂基础日粮，试验组于产后１０日内在基础日粮中添加２．５％的中药复合添加剂（乳泉Ｉ号）。结果表明，试验组仔猪２０日龄窝重和３５日龄断奶窝重分别较对照组提高２５、５９％和２５．９０％（Ｐ＜０．０１）；仔猪断奶个体重提高１８．５６％（Ｐ＜０．０１）；哺乳期平均日增重提高２２、７６％（Ｐ＜０．０１）；哺乳期仔猪成活率提高８．０％（Ｐ＜０．０１）。     

哺乳期饲喂金霉素对母猪繁殖性能的影响

用４０头母猪进行哺乳期饲喂金霉素试验，以确定哺乳期饲喂金霉素（ＣＴＣ）对母猪繁殖性能的影响。结果显示：哺乳期饲喂ＣＴＣ母猪哺乳２１天失重降低２９．５１％，产仔一断奶失重降低１３．７５％。哺乳期母猪饲喂ＣＴＣ可提高随后首次发情受孕率（Ｐ＜０．０１）和总受孕率（Ｐ＜０．０５）。与对照组相比，哺乳期喂ＣＴＣ出生总仔猪数／窝、出生时存活仔猪数／窝、２１日龄和断奶时仔猪数／窝都略有提高（Ｐ＞０．０５）。断奶时仔猪体重也略有提高。对母猪断奶至发情的间隔天数无影响。     

断奶仔猪赖氨酸需求参数的研究

试验选取体重约８千克的杜×大×长三元杂交断奶仔猪（公母各半）７２头，随机分为６组，每组２个重复，每个重复６头猪，分别喂以含赖氨酸（Ｌｙｓ）水平为０．８５，０．９５，１．０５，１．１０，１．１５，１．２０％的饲粮。通过测定饲粮Ｌｙｓ水平对断奶仔猪生产性能和血清氮浓度的影响，探讨断奶仔猪Ｌｙｓ的需求参数。结果表明，随着饲粮中Ｌｙｓ水平的提高，仔猪的平均日增重增加，饲料转化率显著改善（Ｐ＜０．０５），并且在１．１５％的Ｌｙｓ组生产性能达到最佳，进一步提高Ｌｙｓ水平，生产性能反而下降。各组采食量差异不显著（Ｐ＞０．０５）。当饲粮Ｌｙｓ水平由０．８５％升至１．１５％，血清氮浓度无显著差异（Ｐ＞０．０５），但１．２％组极显著地高于其他各组（Ｐ＜０．０１），反映该组猪对蛋白质利用较差，这与该组猪生产性能差相符。以上结论提示，８～１９千克断奶仔猪Ｌｙｓ需求参数为饲粮的１．１５％，按ＡＥＣ（１９８９）有关饲料Ｌｙｓ可消化率数据，折算其相应真可消化和表观可消化Ｌｙｓ为１．０３２％和０．９６７％。     

寡聚糖对仔猪生长性能影响的研究

通过对哺乳仔猪和断奶仔猪饲料中,添加不同量的寡聚饲喂试验。结果表明：在仔猪哺乳期,添加１％寡聚糖能显著降低仔猪腹泻率（Ｐ〈０．０５）,但对仔猪日增重和采食量无显著影响;仔猪断奶后,添加０．１％寡聚糖能显著提高仔猪日增重和饲料报酬（Ｐ〈０．０５）,。减少腹泻率提高饲喂效果。建议在断奶仔猪饲料中添加０．１％寡聚糖,可获较好饲喂效果和效益。     

低聚果糖对仔猪生长性能的影响

６６头体重２０ｋｇ左右的仔猪分成２组，每组３个重复，每个重复１１头，分别饲喂含抗生素和低聚果糖日粮，研究其对仔猪生长性能的影响。结果表明，与抗生素组相比，添加０．１５％低聚果糖组日增重提高４．７１％（Ｐ〉０．０５），采食量提高５．８６％（Ｐ〉０．０５），饲料转化率降低１．２％（Ｐ〉０．０５），生物学综合评定值提高１．８％。由此可见，低聚果糖可替代抗生素应用于仔猪饲饲粮中。     

饲粮中脱毒菜籽饼水平对生长猪的影响

将长白×荣昌杂交一代仔猪（２０ｋｇ左右）７５头随机分成５组，每组１５头。在饲粮中加入占总量的０％、１０％、１５％、１８％和２０％的脱毒菜籽饼，并使供试５种饲粮的营养水平基本相同。经６０天试验，平均日增重，第１、２、３组与第５组差异极显著（Ｐ＜０．０１），第４组与第５组差异显著（Ｐ＜０．０５），第１－４组间差异不显著（Ｐ＞０．０５）。饲料报酬，第１组与第５组差异显著（Ｐ＜０．０５），其他各组间差异不显著（Ｐ＞０．０５）；每千克增重需饲料成本，以第４组最低，第５组最高。     

蛋氨酸铁螯合物在猪日粮中的应用效果

本文对蛋氨酸铁螯合物的研制作一简单介绍,并对母猪和生长猪进行了饲喂试验,试验结果：蛋氨酸铁组比硫酸亚铁组仔猪初生重高５０克／头（Ｐ＞０．０５）,断奶重高０．６公斤（Ｐ＜０．０５）,产仔死亡率降低８．６％（Ｐ＜０．０５）,断奶成活率提高６．２％（Ｐ＜０．０５）,生长猪日增重提高９．５６％（Ｐ＜０．０５）,采食量提高１．８８％（Ｐ＞０．０５）,饲料报酬提高７．０９％（Ｐ＜０．０５）,生长猪血红蛋白含量增加２．３７克／１００毫升（Ｐ＜０．０５）。     

Genetic and phenotypic parameters for sow productivity

Data from 609 purebred Yorkshire, Hampshire and Duroc litters were utilized to obtain genetic and environmental parameter estimates for litter number and weight traits at birth, 21 d (first creep) and 42 d (weaning) considered as traits of the sow. Differences among paternal half-sib sets of sows were analyzed. Heritability estimates from this study were .26 +/- .12, .28 +/- .12 and .30 +/- .12 for litter size at birth, 21 and 42 d and .54 +/- .13, .17 +/- .11 and .15 +/- .11 for litter weights at those times, respectively. These estimates indicated that the dam's genetic contribution to litter weight was higher for prenatal growth than during nursing. The heritabilities for litter size were encouraging for within breed selection. Genetic correlations among litter sizes and genetic correlations among litter weights at birth, 21 and 42 d were large and positive. Large, positive genetic correlations also were found between litter size and weight at each of the three times. Negative correlations between litter size and average pig weight at both birth and 21 d and between litter size at birth and average pig weight at 21 d indicated that larger litters were associated genetically with smaller pigs. Phenotypic and environmental correlations generally indicated the same associations.     

影响杜洛克猪新品系60日龄窝重繁殖性状因素的相关性分析

利用通径分析、决定系数分析及多元逐步回归分析等方法找到了影响杜洛克猪新品系60 d窝重的主要繁殖性状是60 d活仔数、20 d活仔数、60 d个体重及20 d个体重,而初生重、初生窝重和产活仔数影响较小。60 d窝重的最优回归方程为：Y=2.1836X⁴-15.6442X⁵-11.4572X⁶+18.129X⁷+6.9936X⁸-44.6259。     

猪窝产活仔数与初生窝重、21日龄窝重的相关分析

测定84头新关系杜洛克母猪的窝产活仔数、分娩胎次、初生窝重、21日龄窝重,分别按照窝产活仔数分组进行方差分析和性状间的相关回归分析,探讨分娩胎次对猪繁殖性状的影响。结果表明：窝产活仔数、初生窝重、21日龄窝重组间差异均呈极显著（P〈0．01）,初生窝重在窝产活仔猪数为9头和10头,7、8、9头差异不显著,其余各组之间差异显著或极显著。21日龄窝重在窝产活仔数为7、8、9、10、13头之间差异均不显著。对窝产活仔数与分娩胎次、初生窝重、21日龄窝重进行相关分析,分娩胎次与21日龄窝重指标不相关,其余各组指标均达到极显著（P〈0．01）水平。综合分析表明猪窝产活仔数在10～12头可取得最佳经济效益．     

Genetic correlations for litter weight weaned with growth, prolificacy, and wool traits in Columbia, Polypay, Rambouillet, and Targhee sheep

Total litter weight weaned at 120 d postpartum per ewe lambing is often believed to be a measure of range ewe productivity. Genetic correlations for litter weight weaned at 120 d with prolificacy, growth, and wool traits for Columbia, Polypay, Rambouillet, and Targhee sheep were estimated using REML with animal models. Observations per breed ranged from 5,140 to 7,083 for litter weight weaned, from 5,140 to 7,095 for prolificacy traits, from 7,750 to 9,530 for growth traits, and from 4,603 to 18,443 for wool traits. Heritability estimates for litter weight weaned were low and ranged from 0.02 to 0.11. Fraction of variance due to permanent environmental effects averaged 0.05 and, due to effects of mates, averaged 0.01. Estimates of genetic correlations with litter weight weaned varied from breed to breed. The ranges were as follows: 0.42 to 0.65 with litter size born, 0.80 to 0.99 with litter size weaned, -0.22 to 0.28 with birth weight, -0.07 to 0.23 with average daily gain to weaning, -0.56 to 0.19 with fleece weight, -0.15 to 0.02 with fleece grade, and -0.11 to 0.08 with staple length. Results suggest that, if selection were practiced on litter weight weaned, the average correlated responses would be expected to be favorable or neutral for prolificacy, growth, and wool traits although responses might vary from breed to breed.     

Estimates of genetic parameters and genetic change for reproduction,weight, and wool characteristics of Targhee sheep

Genetic parameters from both single-trait and bivariate analyses for prolificacy, weight, and wool traits were estimated using REML with animal models for Targhee sheep from data collected from 1950 to 1998 at the U.S. Sheep Experiment Station, Dubois, ID. Breeding values from both single-trait and seven-trait analyses calculated with the parameters estimated from the single-trait and bivariate analyses were compared across years of birth with respect to genetic trends. The numbers of observations were 38,625 for litter size at birth and litter size at weaning, 33,994 for birth weight, 32,715 for weaning weight, 36,807 for fleece weight and fleece grade, and 3,341 for staple length. Direct heritability estimates from single-trait analyses were 0.10 for litter size at birth, 0.07 for litter size at weaning, 0.25 for birth weight, 0.22 for weaning weight, 0.54 for fleece weight, 0.41 for fleece grade, and 0.65 for staple length. Estimate of direct genetic correlation between litter size at birth and weaning was 0.77 and between birth and weaning weights was 0.52. The estimate of genetic correlation between fleece weight and staple length was positive (0.54), but was negative between fleece weight and fleece grade (-0.47) and between staple length and fleece grade (-0.69). Estimates of genetic correlations were near zero between birth weight and litter size traits and small and positive between weaning weight and litter size traits. Fleece weight was slightly and negatively correlated with both litter size traits. Fleece grade was slightly and positively correlated with both litter size traits. Estimates of correlations between staple length and litter size at birth (-0.14) and litter size at weaning (0.05) were small. Estimates of correlations between weight traits and fleece weight were positive and low to moderate. Estimates of correlations between weight traits and fleece grade were negative and small, whereas estimates between weight traits and staple length were positive and small. Estimated breeding values averaged by year of birth from both the single- and seven-trait analyses for the prolificacy and weight traits increased over time, whereas those for fleece weight decreased slightly and those for the other wool traits were unchanged. Estimated changes in breeding values over time did not differ substantially for the single-trait and seven-trait analyses, except for traits highly correlated with another trait that was responding to selection.     

Estimates of genetic parameters and genetic change for reproduction,weight, and wool characteristics of Columbia sheep

Genetic parameters from both single-trait and bivariate analyses for prolificacy, weight and wool traits were estimated using REML with animal models for Columbia sheep from data collected from 1950 to 1998 at the U.S. Sheep Experiment Station (USSES), Dubois, ID. Breeding values from both single-trait and seven-trait analyses calculated using the parameters estimated from the single-trait and bivariate analyses were compared with respect to genetic trends. Number of observations were 31,401 for litter size at birth and litter size at weaning, 24,741 for birth weight, 23,903 for weaning weight, 29,572 for fleece weight and fleece grade, and 2,449 for staple length. Direct heritability estimates from single-trait analyses were 0.09 for litter size at birth, 0.06 for litter size at weaning, 0.27 for birth weight, 0.16 for weaning weight, 0.53 for fleece weight, 0.41 for fleece grade, and 0.55 for staple length. Estimate of direct genetic correlation between littersize at birth and weaning was 0.84 and between birth and weaning weights was 0.56. Estimate of genetic correlation between fleece weight and staple length was positive (0.55) but negative between fleece weight and fleece grade (-0.47) and between staple length and fleece grade (-0.70). Estimates of genetic correlations were positive but small between birth weight and litter size traits and moderate and positive between weaning weight and litter size traits. Fleece weight was lowly and negatively correlated with both litter size traits. Fleece grade was lowly and positively correlated with both litter size traits, while staple length was lowly and negatively correlated with the litter size traits. Estimates of correlations between weight traits and fleece weight were positive and low to moderate. Estimates of correlations between weight traits and fleece grade were negative and small. Estimates of correlations between staple length and birth weight (0.05) and weaning weight were small (-0.04). Estimated breeding values averaged by year of birth from both the single-trait and multiple-trait analyses for the prolificacy and weight traits increased over time, but were unchanged for the wool traits. Estimated changes in breeding values over time did not differ substantially for single-trait and multiple-trait analyses, except for traits highly correlated with another trait that was responding to selection.     

尾部连续采血法对香猪母猪繁殖性能的影响

本项研究选用畜牧试验站内12头成年、后备香猪母猪各6头,在配种前1～2天及配种后6天的上午9:00～11:00点间,间隔10分钟,进行尾部采血,收集血样12次,观察采血对母猪情期受胎率、仔猪初生重。75天断乳重及产仔数的影响。结果表明:尾部连续采血法对母猪繁殖机能及仔猪发育无不良影响。此法简单,易学,宜于在生产中普遍应用。     

新太湖猪选育过程中近交技术的应用及效应分析

利用新太湖猪选育过程中（１９８６～１９９４）６个世代母猪的分娩产仔记录,后备猪生长发育测定资料,分析了近交对繁殖性能和生长发育性状的影响。相关分析表明,近交与产仔数、产活仔数的相关系数分别为－０．１６２５、－０．１５４６。与１８０日龄活重、体高、胸围、及８０ｋｇ时背膘厚度的相关系数分别为－０．１３５,－０．２１１,－０．２１８,－０．２０４。回归分析表明,近交系数每上升１０％,产仔数下降０．３９头,１８０日龄活重下降１．５ｋｇ,背膘厚下降０．０７４８ｃｍ。产仔记录分析表明,母猪近交系数在２０％以下时,产仔数比非近交组下降０．２７头,差异不显著（Ｐ＞０．０５）;近交系数在２０％以上时,下降１．３５头,差异不显著（Ｐ＞０．０５）。生长发育性状表明,近交系数在３０％以上时,１２０日龄活重、１８０日龄活重等性状都显著下降。８０ｋｇ活体背膘厚当个体近交系数上升到２０％以上时,与非近交组相比下降０．１６ｃｍ,差异显著（Ｐ＜０．０５）。     

Heterosis and recombination effects on pig reproductive traits

The objective was to estimate breed, heterosis, and recombination effects on pig reproductive traits in two different four-breed composite populations. Breeds included Yorkshire, Landrace, Large White, and Chester White in Exp. 1 and Duroc, Hampshire, Pietrain, and Spot in Exp. 2. Data were recorded on purebred pigs, two-breed cross pigs, and pigs from generations F1 through F6, where F1 pigs were the first generation of a four-breed cross. Litter traits were considered a trait of the gilt. There were 868 first parity litters in Exp. 1 and 865 in Exp. 2. Direct heterosis significantly increased sow weight at 110 d of gestation and litter weight at 14 and 28 d (weaning) in both experiments. Direct heterosis significantly increased number of nipples, weight at puberty, lactation weight loss, litter size, and litter birth weight in Exp. 2. Gestation length in Exp. 1 and age at puberty in Exp. 1 and Exp. 2 were significantly decreased by direct heterosis. Maternal heterosis significantly increased age at puberty in Exp. 2 and decreased sow weight at 110 d of gestation in Exp. 1. Recombination significantly increased sow weight at 110 d of gestation and tended to increase total number born and litter birth weight in Exp. 1. Recombination significantly decreased age at puberty in Exp. 2. Litter heterosis significantly increased number of pigs at 14 and 28 d; litter weights at birth, 14, and 28 d; and tended to increase lactation weight loss in Exp. 1. Litter heterosis decreased litter size in Exp. 2. Maternal heterosis and recombination effects had a sampling correlation of -0.97 in Exp. 1 and -0.91 in Exp. 2 for number of fully formed pigs. Therefore, maternal heterosis and recombination effects were summed, and their net effect was tested. This net effect tended to increase number of nipples, lactation weight loss, and litter birth weight and significantly increased number of fully formed pigs in Exp. 1. Direct, maternal, and litter heterosis and recombination effects significantly influenced reproductive traits.     

Flushing and altrenogest affect litter traits in gilts

Gilts (n = 267) were allotted to flushing (1.55 kg/d additional grain sorghum), altrenogest (15 mg.gilt-1.d-1) and control treatments in a 2 x 2 factorial arrangement. Altrenogest was fed for 14 d. Flushing began on d 9 of the altrenogest treatment and continued until first observed estrus; 209 gilts (78%) were detected in estrus. The interval from the last day of altrenogest feeding to estrus was shorter (P less than .05) with the altrenogest + flushing treatment (6.6 +/- .2 d) than with flushing alone (7.6 + .3 d). Ovulation rates (no. of corpora lutea) were higher (P less than .05) in all flushed gilts (14.5 +/- .4 vs 13.4 +/- .4), whether or not they received altrenogest. Flushing also increased the total number of pigs farrowed (.9 pigs/litter; P = .06) and total litter weight (1.43 kg/litter; P = .01), independent of altrenogest treatment. Number of pigs born alive and weight of live pigs were higher for gilts treated with altrenogest + flushing and inseminated at their pubertal estrus than for gilts in all other treatment combinations. In contrast, gilts receiving only altrenogest had greater live litter weight and more live pigs born when inseminated at a postpubertal estrus than when inseminated at pubertal estrus. We conclude that flushing increased litter size and litter weight, particularly for gilts that were inseminated at their pubertal estrus. Increased litter size resulted from increased ovulation rates, which, in nonflushed gilts, limited litter size at first farrowing.