贵州白香猪不同杂交组合后代生长发育指标的测定

试验选用贵州白香猪作为母本,分别以大约克猪、杜洛克猪、长白猪作为父本进行杂交组合试验,测定了3个杂交组合F1代及对照组香猪的初生重、20日龄重及2～6月龄的生长发育指标。结果表明,初生重为杜×香大×香长×香香猪,长×香组与对照组香猪间差异不显著(P0.05);20日龄重为杜×香大×香长×香香猪。生长发育各指标间差异显著,并且随着月龄增加各试验组间生长发育显著性增大,除2月龄体长为杜×香大×香长×香香猪、3月龄体重,体长、胸围、腹围指标及5月龄体高、体长指标为大×香长×香杜×香香猪外,其余月龄生长发育各指标为大×香杜×香长×香香猪。     

不同断奶日龄对奶公犊生长性能和体尺指标的影响

30头新生荷斯坦奶公犊出生日期和体重相近,随机分成6组,对照组按常规饲喂鲜牛奶,60日龄断奶;各试验组分别于10、20、30、40和50日龄断奶,试验期为60d。结果表明:试验结束时,20日龄断奶组、30日龄断奶组的体重、平均日增重均显著高于对照组,40日龄断奶组、50日龄断奶组与对照组间无明显差异;各试验组犊牛与对照组在体长和体斜长上无显著差异。     

大约克夏猪肥育性状的选育研究

通过群体继代选育法来提高大约克夏猪的肥育性状，通过连续7个世代的选育，每个世代随机抽取24头猪作肥育试验。结果表明：大约克夏猪的断奶体长增长了7．66％，6月龄体长增长百10．19％；断奶体重增长了5．83％，60日龄体重增长了16．84％；育肥猪平均日增重提高了127．50g，科肉比下降了16．47％。     

不同三元杂交组合猪的育肥性能测定

为了充分挖掘地方良种母猪———小梅山猪的潜力 ,提高农民的养猪效益 ,满足市场对商品肉猪瘦肉率的需要 ,我县于1997年承担了国家 97140 10 2Ａ科研项目 ,并于 1998年 8月至 12月在县种猪场对长×皮梅 ,长×大梅商品猪进行育肥性能测定 ,试验结果如下。1　材料与方法1 1　试验动物及其分组试验动物均来自县种猪场。选择健康、三胎以上的皮梅、大梅二元母猪与丹麦长白公猪所产仔猪 ,在 80日龄时分成长×皮梅和长×大梅 2个试验组 ,试验猪经过阉割和猪三联苗免疫。在预试期 1周结束时剔除组内个别体型小的猪 ,使各组试验猪的体重、大小基本一…     

益生素对断乳仔猪生产性能的影响

试验选用体质健康的34日龄乳仔猪，随机分成两组，Ⅰ组（试验组）10头，Ⅱ（对照组）6头；设一重复。Ⅰ组在基因日粮中添加益生素0．4％，Ⅱ组饲喂基础日粮；研究益生素对断乳日龄仔猪生产的影响。结果表明：Ⅰ组仔猪62日龄时的平均体重为18.82kg，腹泻的发生率为10．0％；Ⅱ组仔猪62日龄时的平均体重为19.33kg，腹的发生率为16．7％。Ⅰ组试猪与Ⅱ组试猪相比，体重差异不显著（P＞0．05），日增重及料肉比，亦相近，但腹泻率有所降低。     

不同饲养方式下合作猪的生长性能

通过舍饲养殖,研究不同饲养方式下合作猪的生长性能。结果显示:1～6月龄舍饲组合作猪体重、体高、体长、胸围均极显著高于放牧组(P<0.01);头长和管围差异不显著(P>0.05)。合作猪初生～1月龄、3～6月龄日增重,放牧组显著低于舍饲组(P<0.05);1月龄到3月龄日增重,2组差异不显著(P>0.05)。2组合作猪绝对生长在6月龄为最大,放牧组为103.00 g,舍饲组为150.67 g。2组合作猪相对生长系数随日龄的增加而下降,体重的生长强度随月龄的增加逐渐减小。     

影响沙子岭猪6月龄体重有关性状相关分析及综合选择指数的研究

本文应用通径分析方法,研究了沙子岭猪6月龄体重与体长、胸围、体高、胸宽之间的相关关系,找出了影响6月龄体重的主要性状是胸围,其次是体长和胸宽,而体高对6月龄体重的直接影响最小。本文制订了一个对沙子岭猪6月龄体重进行直接选择,胸围、体长进行间接选择并用的综合选择指数公式:I=0.1599y-0.0694x1-0.0917x2。用这个公式选种,效果将比单纯直接选择要好。     

DM423菌粉制剂饲喂育肥猪试验

畜禽日粮在各种营养平衡的前题下,利用生物发酵技术可进一步提高饲料报酬。菌种的代谢特点是发酵各个环节中的关键。通过本次试验,寻求一种质优价廉的微生物添加应用于生产实践。 一、材料及方法 1、试验猪及分组:选择体重、日龄相近,成窝健康的长荣及药荣杂交仔猪45头,按品种、性别、体重配对分别分为3组,每组15头,随机定为对照组(不添加DM423),试验一组(添加0.02％DM423),试验二组(添     

不同品种的后备种猪、头胎种猪和二胎种猪体尺指标相关性研究

试验旨在研究不同品种美系后备母猪、头胎母猪和二胎母猪体尺指标参数,为后备猪的选留、头胎猪和二胎猪的饲养管理提供依据。试验选择200日龄左右的大白、长白和杜洛克后备猪1 258、372和236头;头胎(头胎产仔结束测定)大白、长白和杜洛克种猪405、127和70头;二胎(二胎产仔结束测定)大白、长白和杜洛克种猪180、62和21头,进行种猪体尺指标体长、体高、胸围和管围的测定。试验结果表明:在测定日龄相近的情况下,后备猪长白和杜洛克体尺指标接近,体重、体高、胸围和管围杜洛克略高于长白;体长长白高于杜洛克。头胎和二胎结束后大白、长白和杜洛克种猪的体尺指标都比后备期有大幅度提高。在头胎结束时,杜洛克种猪体高、胸围和管围是最大的,分别为(75.69±4.0) cm、(133.31±5.96) cm和(21.70±1.30) cm,长白的体长是最长的为(139.98±7.67) cm;在二胎结束时,同样得到了与头胎结束一致的体尺测定结果。杜洛克种猪体高、胸围和管围是最大的,分别为(78.42±3.36) cm、(139.28±6.36) cm和(22.23±1.7) cm,长白的体长是最长的为(150.11±7.81) cm。试验结果表明,不同品种后备猪体尺指标之间存在差异,不同品种具有各自优势项目,可以把体尺指标作为后备猪、头胎猪和二胎猪选育的依据之一。     

新美系猪生长肥育性能测定分析

为测定新美系猪生长肥育性能,试验选择生长发育正常、体重33.77 kg左右、系谱档案完整的新美系长白、大白、杜洛克和巴克夏母猪各12头,按品系分4栏饲养。预试期7 d,正试期83 d。试验期间,各品系猪饲喂相同营养水平饲粮(前期消化能13.58 MJ/kg,粗蛋白质16.07%;后期消化能13.40 MJ/kg,粗蛋白质14.66%),饲养试验结束时用B超测定试猪活体背膘厚。结果表明,试验全期,日增重,大白猪最高为780.12 g,巴克夏猪最低为702.93 g,大白猪日增重比巴克夏猪日增重显著高10.98%;料重比,大白猪最低为2.54,巴克夏猪最高为2.96;达100 kg体重日龄,长白猪、杜洛克猪和巴克夏猪分别比大白猪(164.02 d)多1.05 d、2.4 d和4.03 d,但各品系之间无显著性差异(P0.05);达100 kg体重背膘厚杜洛克猪最低为10.72 mm,巴克夏猪最高为12.44 mm,但各品系之间无显著性差异(P0.05)。综上所述,在该试验条件下,新美系长白猪和大白猪的生长肥育性能较好,杜洛克猪次之,巴克夏猪较差。     

Effects of divergent selection for leg weakness on angularity of joints in Duroc swine

Sixty Duroc pigs, representing offspring of three lines from the fifth generation of divergent selection for leg weakness, were examined to determine correlated responses in joint angularity. The lines were low, control, and high, with the latter having superior front leg structure. At approximately 100 kg, 10 pigs of each sex and line were scored for front and rear leg structure and movement. The shoulder, elbow, carpal and hock joints were measured for resting angles and range of motion. The model to analyze the data included the effects of line, sire, sex and side and covariable for weight. High-line pigs had significantly smaller (P less than .05) resting angles of the elbow joint than did control- or low-line pigs. The low-line pigs, however, had significantly smaller resting angles at the carpal joint (P less than .01) and greater resting angles at the hock joint (P less than .05) than did control- or high-line pigs. The low-line pigs had fewer degrees extension at the elbow joint and fewer degrees flexion at the carpal joint than did control- or high-line pigs. High-line pigs had fewer degrees of flexion of the elbow joint than did control-or low-line pigs. Resting angles and range of motion for the elbow and carpal joints were less on the left side than on the right side. Males had greater degrees of extension and total degrees of movement at the elbow joint than did females. Selection for different degrees of leg weakness resulted in accompanying alterations in angularity of joints.     

Effect of dietary sodium bicarbonate on leg structure in Duroc swine that differ genetically for leg weakness

Two trials were conducted to evaluate the effect of dietary replacement of .30% sodium chloride (NaCl) with a sodium-equivalent amount of sodium bicarbonate (NaHCO3) on leg weakness in swine. Three lines of Duroc swine established by six generations of divergent selection for front leg structure were used. In the first trial, a total of 80 low-line (increased leg weakness), 75 high-line (decreased leg weakness), 80 control-line (intermediate leg weakness) and 80 high x low pigs were used. Pigs were assigned within litter to an experimental or control diet and tested from approximately 37 to 104 kg live weight. The experimental diet contained .43% NaHCO3, replacing .30% NaCl in the control diet. Pigs had ad libitum access to feed. In the second trial, 48 high- and 48 low-line pigs were fed the same diets from 29 to 104 kg. At the completion of each trial, pigs were scored for various leg traits. The model used for statistical analyses included the effects of replicate, genetic line, dietary treatment and the dietary treatment x genetic line interaction. Trials were analyzed separately. Results indicated that there was no significant improvement in clinical signs of leg weakness due to dietary supplementation with NaHCO3 for front leg structure and movement, rear leg movement or rear toe size. Rear hock angle was improved in Trial 1 (P less than .05) but was reduced in Trial 2 (P less than .10).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of divergent selection for limb weakness on bone and muscle cross-sectional areas in Duroc swine

The relationship of muscle and bone structure to limb weakness was examined in 60 Duroc pigs from 3 lines divergently selected for thoracic limb weakness. The lines were designated high, control, or low, with the low line having inferior thoracic limb structure. At approximately 100 kg, 10 pigs of each line and gender were scored for thoracic limb structure and movement. Right and left thoracic limbs were collected at slaughter. A computerized morphometric image analysis system was used to determine cross-sectional areas of muscles, bones, and soft tissues at levels through the brachium, antebrachium, metacarpus, and digits. The statistical model that was used to analyze the data included the effects of line, sire, gender, and side (left vs right), with weight as a covariate. Total bone area was similar for all 3 lines of pigs at all cross-sectional levels, but significant differences in muscle and other soft tissue areas were observed, including significantly greater extensor area for the antebrachium (P less than 0.001) in low-line pigs than in control- and high-line pigs, smaller total area (P less than 0.05) of the metacarpus in low-line pigs than in control and high-line pigs, and less total area of the medial digit (P less than 0.01) in low-line pigs than in control- or high-line pigs. Total area of bone and soft tissue for each cross-sectional region was significantly greater (P less than 0.05) in boars than in gilts. Side differences also were observed in total cross-sectional areas of bone and soft tissue of the antebrachium, metacarpus, and digits.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rate of claw horn growth and wear in biotin-supplemented and non-supplemented pigs

The growth and wear rate of claw horn was measured in 42 commercial hybrid pigs. Half received a ration supplemented with 1 mg d-biotin/kg food daily, while the others acted as controls. The start weights of three replicates of 10 pigs averaged 25 kg and their mean finishing weight was 85 kg. Twelve pigs averaged 18 kg at the start and 118 kg at the end of the experiment. No differences in horn growth and wear rates were found between the biotin-supplemented pigs and the controls, or between the front and hind claws, although horn growth and wear both decreased with age. Claw horn grew at an average of 10 mm/28 days in the pigs taken from 25 to 85 kg bodyweight and at 11 mm/28 days in the pigs taken from 18 to 118 kg. The mean rate of wear of claw horn was 6 mm/28 days.     

The effect of divergent selection for uterine capacity on fetal and placental development at term in rabbits: maternal and embryonic genetic effects

The aim of this work was to study the effects of the genotype of the dam, the embryo, or their interactions on prenatal growth by performing double-reciprocal embryo transfers between two lines of rabbits divergently selected for uterine capacity. Females from high (n = 53) and low (n = 48) lines were slaughtered at 72 h of gestation, and recovered embryos were transferred to the oviducts of recipient does from the high (n = 23) and low (n = 19) lines. Each recipient doe received eight embryos from the high line into one oviduct and eight embryos from the low line into the other. Recipient does were slaughtered on d 28 of gestation. The percentages of live fetuses at 28 d of gestation were 89.2 and 74% for high and low recipient lines, respectively. Length and weight of the empty uterine horn and weight of the full uterine horn were not affected by either the recipient or by donor line. Fetal weight was affected by the recipient line but not by the donor line. Fetuses gestated in high recipient does were 7% heavier (P < 0.10) than those in the low recipient does. There was a donor and a donor x recipient interaction effect on fetal placental weight. Fetal placental weight was heavier (7%, P < 0.01) for embryos from the low line. Embryos from the high line gestated in low-line uteri showed a lower fetal placenta weight than did low-line embryos gestated in high-line uteri and low-line uteri (P < 0.05). Linear regression coefficients of fetal weight at term on fetal placental weights differed (P < 0.05) for the high and low donors (4.33 +/- 0.28 and 3.41 +/- 0.29 respectively). A significant effect of the donor genotype on individual placental length was observed (P < 0.05), which might have resulted from a smaller individual placental length of low-line embryos gestated high-line uteri (P < 0.10). Neither donor nor recipient lines affected maternal placental weight or available space for fetuses. Fetuses and their fetal placentae were heavier when receiving more than four blood vessels than when receiving less than three blood vessels (13 and 17% respectively, P < 0.05). Neither recipient nor donor genotype affected the number of blood vessels arriving at each live fetus. Thus, fetal weight depends on the maternal genotype, whereas fetal placental weight depends on the embryo genotype in these two lines of rabbits divergently selected for uterine capacity.     

Body and claw measurements and pressure distribution under the claws in calves of different cattle breeds

In 58 female calves of the three breeds German Holstein (GH), German Brown (GB) and German Red (GR) the body weight and height were determined at the age of 79 to 188 days. At the right front limb and the left hind limb the following claw measurements were taken: dorsal border length, diagonal length, heel length and height, angle of the dorsal border and hardness of the claw horn. Furthermore, the punctual pressure under the medial and the lateral claw of the right front limb and the left hind limb were determined using an electronic measuring system. The GH calves weighing 136.8 kg were heavier than GB, which was the tallest breed with 106.2 cm height at the sacral bone. GR calves were the smallest (99.1 cm) and weighed 121.1 kg. The length of the diagonal and the angle of the dorsal border were smaller at the hind limb of all breeds which resulted in a smaller area of ground surface for the claw of this limb. The GR calves had the longest and flattest claws. The GB showed the highest pressures per cm2 at the front limb with 25.6 N/cm2 under both claws as well as at the hind limb with 26.7 N/cm2. The AR had the smallest pressure load with 20.8 N/cm2 at the front limb and 20.2 N/cm2 at the hind limb. The animals showed a larger relative weight load and area of ground surface on the medial claws of the front and hind limbs than on the lateral claws. The highest pressures were found underneath the rear part of the medial claw in all breeds. GB calves showed the highest average pressures (33.3 N/cm2 at the front limb) while GR calves had the lowest (26.3 N/cm2 at the hind limb). GR calves had the highest claw hardness at all measuring positions.     

Body and claw measurements as well as pressure distribution under the claws in heifers of different cattle breeds

In 56 heifers of the three breeds German Holstein (GH), German Brown (GB) und German Red (GR) the body weight and height were determined at the age of 350 to 550 days in intervals of 6 to 8 weeks. At the right front limb and the left hind limb the claw measurements dorsal wall length, diagonal length, heel length and height, the angle of the dorsal wall and the hardness of the claw were taken. Furthermore, the punctual pressure under the medial and the lateral claw of the right front limb and the left hind limb were determined using an electronic measuring system. The GH heifers weighing 387.3 kg on an average and having a mean height of 132.3 cm at the sacral bone in the course of the present study were the heaviest and tallest breed at the age of 12 to 18 months. GB had a weight of 366.2 kg and 106.2 cm height at the sacral bone. The GR were the smallest breed (126.0 cm) and weighed 337.7 kg. The heel at the front limb was on the average 1 cm shorter than at the hind limb and it was 0.5 cm lower. The angle of the dorsal border was 4-5 degrees higher at the hind limb. The GR had the flattest claws. The animals showed a larger average weight load on the medial claws than on the lateral claws especially of the front limbs. The highest pressures per cm2 were found underneath the rear part of the medial claw in all breeds. At the front limb, the GB showed significantly higher average pressures per cm2 under the front sectors of the claws than GH and GR, while the other values did not differ significantly between the breeds. The GH tended to have lower average pressures per cm2 underneath the claws of the hind limb, but this was only significant at the front medial sector of the claw.     

Osteochondrosis/osteoarthrosis and claw disorders in sows, associated with leg weakness

The objective of this study was to investigate the associations between different leg weakness symptoms and osteochondrosis/osteoarthrosis and claw disorders in sows together with the influence of age on these findings. One hundred and seventeen sows in one herd were followed from 6 months of age until culling and judged for leg weakness once in every gestation using a scale from 1 (normal) to 4 (severe changes). At slaughter changes in joints, growth plates and claws were scored on a scale from 1 (normal) to 5 (very severe changes). Osteoarthrotic changes were strongly associated with osteochondral changes in humeral and femoral condyles. The clinical signs of osteochondrosis and osteoarthrosis were found to be: buck-kneed forelegs, turn out of fore and hind legs, upright pasterns on hind legs, stiff locomotion, lameness and tendency to slip. The clinical signs of claw lesions were found to be: buck-kneed forelegs, upright pasterns, steep hock joints, turn out of hind legs, standing under position on hind legs, stiff movements, swaying hindquarters, goose-stepping hind legs, tendency to slip and lameness. Overgrown claws were strongly associated with leg weakness indicating the need for claw trimming in sow populations.     

Relationship between Mycoplasma hyosynoviae infection and front limb weakness in Duroc swine

A relationship between degree of Mycoplasma hyosynoviae infection and front limb soundness was examined in 254 Duroc swine. These pigs represented 3 lines of pigs (structurally sound, control, and unsound) from a population divergently selected for 4 generations for front limb soundness. Analysis of sera collected every 4 weeks between 6 and 26 weeks of age yielded complement-fixing antibody titers that were believed to be indicative of the degree of natural infection with M hyosynoviae. Analysis of several variables defined by using titer values failed to reveal significant differences among the 3 selected lines, but trends indicated higher mean and peak titer values for pigs from the unsound line. Correlations between titer variables and front limb soundness variables within genetic groups were low and not significantly different from zero. Correlations between all titer variables were calculated; the correlation between mean titer and peak titer was 0.81 (P less than 0.01), and between mean titer and age at detection of first titer, was -0.56 (P less than 0.01). Pooled heritability estimates were 0.51 +/- 0.28 for mean titer and 0.28 +/- 0.25 for peak titer.     

Effects of Duroc, Meishan, Fengjing, and Minzhu boars on productivity of mates and growth of first-cross progeny.

Meishan, Fengjing, Minzhu, and Duroc boars were mated by AI to crossbred gilts to compare the sire breeds for effects on productivity of their mates and performance of their progeny. Gilts were derived from a four-way cross of Chester White, Landrace, Large White, and Yorkshire. At weaning, litters sired by Meishan boars averaged 1.69 and 1.32 more pigs than those sired by Duroc and Minzhu boars, respectively (P less than .05). Pigs sired by Meishan and Fengjing boars averaged 1.2 to 1.8 more nipples than pigs sired by Duroc and Minzhu boars (P less than .05). Minzhu-sired pigs had a lower (P less than .05) survival rate to 14 and 28 d of age than did those sired by Meishan, Fengjing, and Duroc. Fengjing-sired pigs were heavier than Minzhu-sired pigs at birth and heavier than Minzhu- and Duroc-sired pigs at 14, 28, and 56 d of age (P less than .05). At 70 d of age, Meishan-sired pigs were heaviest, followed in order by Fengjing-, Duroc-, and Minzhu-sired pigs. At 98 d of age, Meishan-sired pigs were significantly heavier than all other breed groups and Duroc-sired pigs were significantly heavier than Minzhu-sired pigs. At 126 and 154 d of age, Duroc-sired pigs were heaviest, followed in order by Meishan-, Fengjing-, and Minzhu-sired pigs; all differences were significant. Average backfat thickness of gilts at 99.7 kg was least for Duroc-sired gilts and highest for Meishan-sired gilts. Sire breed groups did not differ significantly in feed efficiency from 70 to 98 d of age. Duroc-sired pigs were the most efficient (P less than .05) from 98 to 126 and 126 to 154 d of age. Results indicate that use of these Chinese breeds in crossbreeding programs will decrease performance traits. This decrease would have to be offset by increases in reproductive efficiency of Chinese sows, use of repartitioning agents, or other management techniques if Chinese pigs are to improve overall production efficiency of a crossbreeding program.