当年母羔当年配种对母羊及其所产羔羊生产性能的影响

选择2005年1～2月出生的母羔,10月份参加配种,次年3月份产羔,测定当年母羔10月龄达参配体重比例、发情率、受胎率,来年所产羔羊与成年母羊所产羔羊的初生体重、双羔率、健羔率、死亡率;产羔与未产羔的周岁母羊的生产性能。结果表明,当年母羔10月龄配种体重达到要求参配体重(38kg)比例为70%,两情期发情率为87.3%,受胎率为82.4%。周岁母羊所产羔羊比成年母羊所产羔羊初生重、双羔率分别低0.25g和3%,差异均不显著(P>0.05)。健羔率低6.2%,死亡率高出2.6%,差异显著(P<0.05)。产羔周岁母羊与未产羔周岁母羊相比,剪毛长度短0.44cm,剪毛量、净毛率、净毛量、剪毛后体重低分别低0.53kg、2%、2.06kg、3.1kg,差异均不显著(P>0.05)。     

周岁母羊配种产羔对其生产性能的影响

选择2005年1～2月出生的母羔,10月份参加配种,次年3月份产羔,测定当年母羔10月龄达参配体重比例、发情率、受胎率,来年所产羔羊与成年母羊所产羔羊的初生体重、双羔率、健羔率、死亡率;产羔与未产羔的周岁母羊的生产性能。结果表明:当年母羔10月龄配种体重达到要求参配体重(38kg)比例为70%,两情期发情率为87.3%,受胎率为82.4%。周岁母羊所产羔羊比成年母羊所产羔羊初生重、双羔率分别低0.25g、3%,差异均不显著(p>0.05)。健羔率低6.2%,死亡率高出2.6%,差异显著(p>0.05)。产羔周岁母羊与未产羔周岁母羊相比剪毛长度短0.44cm,剪毛量、净毛率、净毛量、剪毛后体重低分别低0.53kg、2%、2.06kg、3.1kg,差异均不显著(P>0.05)。     

湖羊精液稀释配种效果观察

本试验旨在研究湖羊精液稀释配种对母羊第一情期受胎率和产羔数的影响,通过同期发情方法对120头母羊进行处理,对确认发情的115头母羊分3组,分别作原精、2倍稀释、4倍稀释配种,跟踪第一情期受胎及母羊产羔情况。结果表明:2倍精液稀释配种组的母羊第一情期受胎率与原精配种组无显著差异(P>0.05),4倍精液稀释配种组的母羊第一情期受胎率显著低于前两组(P<0.05);但三组母羊平均产羔数无显著差异(P>0.05)。     

规模舍饲山羊的主要繁殖性能

文章对盐亭汇源牧业有限责任公司种羊场2002～2005年山羊的繁殖生产记录资料和部分质量性状进行了统计分析.结果表明,在舍饲条件下,山羊全年均可发情,但配种季节主要集中在春、秋两季,尤以秋季最为集中;使用人工授精技术的受胎率达到自然发情配种母羊的受胎率;产单羔母羊的妊娠期极显著和显著地长于产双羔和三羔的母羊;不论公、母,单羔的平均初生重极显著高于双羔和三羔;出生双羔公羊的初生重显著高于三羔,双羔和三羔母羊的初生重无显著差异;窝产单羔和双羔时,公、母羔的初生重差异极显著,而窝产三羔时,公、母羔的初生重无显著差异;有胡须母羊的平均窝产羔数比无胡须母羊的平均窝产羔数高8.26%,无角母羊的平均窝产羔数比有角母羊的平均窝产羔数高5.70%,有肉髯母羊的窝产羔数高于肉髯母羊.     

湖羊保种性选育初报

多胎和特殊羔皮花纹是湖羊主要的品种特点之一,为维持和提高这两个性状,分别组建了多羔和羔皮保种性选育核心群,经过3个世代封闭纯繁选育,初步形成了以第2胎为主、4个公羊家系、10头公羊和38头基础母羊组成的多羔系,16头公羊和55头基础母羊组成的羔皮系纯繁选育核心群。多羔系核心群平均同胞数3．2头,公、母羊平均初生重分别为3．13kg和2．71kg;选育群平均产羔头数由第1世代的3．00头增加到第3世代的3．60头,3个世代平均选育进展为0．30头。羔皮系核心群特级羔皮公、母羊比例分别为87．50％和76．36％,一级羔皮公、母羊比例分别为12．50％和23．64％,公、母羊平均初生重分别为3．50kg和2．94kg,群体平均同胞数为2．08头;选育群特级羔皮公、母羊比例分别由第1世代的45．45％和50．00％增加到第3世代的84．62％和72．73％,公母羊平均选育进展分别为19．59％和11．37％。获得了较好的保种选育效果,为湖羊优良种质资源保护贡献了力量。     

湖羊保种性选育初报

多胎和特殊羔皮花纹是湖羊主要的品种特点之一,为维持和提高这两个性状,分别组建了多羔和羔皮保种性选育核心群,经过3个世代封闭纯繁选育,初步形成了以第2胎为主、4个公羊家系、10头公羊和38头基础母羊组成的多羔系,16头公羊和55头基础母羊组成的羔皮系纯繁选育核心群。多羔系核心群平均同胞数3．2头,公、母羊平均初生重分别为3．13kg和2．71kg;选育群平均产羔头数由第1世代的3．00头增加到第3世代的3．60头,3个世代平均选育进展为0．30头。羔皮系核心群特级羔皮公、母羊比例分别为87．50％和76．36％,一级羔皮公、母羊比例分别为12．50％和23．64％,公、母羊平均初生重分别为3．50kg和2．94kg,群体平均同胞数为2．08头;选育群特级羔皮公、母羊比例分别由第1世代的45．45％和50．00％增加到第3世代的84．62％和72．73％,公母羊平均选育进展分别为19．59％和11．37％。获得了较好的保种选育效果,为湖羊优良种质资源保护贡献了力量。     

简州大耳羊繁殖性能选育研究及遗传进展分析

对简州大耳羊核心群世代选育母羊繁殖性能进行了系统测定。简州大耳羊发情周期平均为20.66 d,发情持续期为48.52 h,妊娠期平均为148.76 d;初产母羊平均产羔率为153.51%,经产母羊为242.41%;年均产羔1.75胎;公羔平均初生重为3.10 kg,母羔平均初生重为2.95 kg。结果表明简州大耳羊具有多胎、多羔,常年发情产羔,羔羊初生重较大,繁殖性能好的优良特性。通过世代选育,简州大耳羊繁殖性能取得了一定的遗传进展,四世代初产母羊产羔率比零世代提高了3.39%;四世代公羔初生重比零世代提高了9.15%,母羔初生重比零世代提高了7.66%。研究结果揭示了简州大耳羊的发情、配种、产羔等繁殖规律,表明简州大耳羊具有较高的繁殖力,并随胎次的不同而异,而且各世代间稳定性好。     

规模猪场种猪配种、怀孕阶段饲养管理操作技术规程

①每周负责配种30头母猪,确保受胎率达85％以上,分娩率达98％以上,头胎窝平产健壮仔9头以上,初生重1．3kg以上,经产窝平产健壮仔10头以上,初生重1．45kg以上,种猪死亡率控制在3％。     

简阳大耳羊繁殖性能研究

利用简阳大耳羊新品种世代选育过程中的系统资料,对简阳大耳羊繁殖性能进行了系统研究。结果表明:简阳大耳羊发情周期平均20.66 d,发情持续期平均48.52 h,妊娠期平均148.76 d;母羊全年均可繁殖配种、产羔,全年产羔仍然遵循"春配秋产、秋配春产"的规律;四世代初产母羊平均产羔率153.51%,经产母羊242.41%;年均产羔1.75只;四世代公羔平均初生重3.10 kg,母羔平均初生重2.95 kg。表明简阳大耳羊具有多胎、多羔,常年发情产羔,羔羊初生重较大,繁殖性能好的优良特性。     

提高绵羊繁殖率的措施

1适当提高适龄母羊在羊群中的比例让适龄母羊在群中比例占到60%以上,是提高绵羊繁殖率的重要途径。应把老龄母羊逐步淘汰,补充幼龄母羊,使适龄母羊数不断增大。2改善饲养管理改善公母羊的营养状况,抓好绵羊膘不仅能使母羊发情整齐,也能使其排卵数增加,能使弱羊双羔率增加,配种季节多喂青绿多汁饲料,在怀孕期,加强饲养管理,防止死胎,喂好种公羊,能使母羊受胎率提高,羔羊初生重大。产羔率增高。3适时配种绵羊配种不适时,会影响种羊精液质量及发情、排卵,10～11月配种,来年3～4月产羔最好。 4淘汰不孕羊参加配种的全群母羊,配种…     

Evaluation of the ovine callipyge locus: IV. Genotypic effects on reproductive traits

A resource population of ewes derived from Dorset and Romanov grandparents was generated over 5 yr to provide genotypic and phenotypic data to estimate effects of each callipyge genotype on component traits of reproduction. Effects on ovulation rate were estimated from data recorded by examination of ovaries from serially slaughtered ewe lambs (n = 174) born in 1994 and 1995. Productivity and longevity through 5 yr of age were recorded on a total of 265 F2 ewes produced in 1996 through 1998. Number of lambs born, birth weights, and weaning weights of lambs were calculated for each ewe. Weaning weight was recorded for each lamb and adjusted for age to 56 and 32 d for dam- and nursery-reared lambs, respectively. Longevity was determined as a binary trait based on the presence or absence of the ewe in the breeding flock at 5 yr of age. Ewes generated 937 records for breeding weight and 925 records for conception rate, which was determined on ewes exposed and still present at the start of each lambing season. Seven hundred seventeen records were analyzed for traits based on the number of ewes lambing. Genotypes for the causative callipyge mutation were determined using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry assay. Each ewe was classified into 1 of 4 genotypes; NMatNPat, NMatCPat, CMatNPat, or CMatCPat, where N represents wild type and C represents the mutant allele. The mean ovulation rate of the ewe lambs genotyped NMatNPat was greater (P < 0.02) than that exhibited by NMatCPat; however, the estimated difference of 0.25 ovum in the ewe lambs did not affect the number born. The live weight of NMatCPat ewes at breeding was 2.5 kg less than that of other genotypes (P < 0.01). The callipyge genotype class did not significantly affect conception rates, fecundity, maternal ability, or ewe longevity. Maintaining a ewe flock to produce homozygous mutant rams for use in terminal sire mating systems presents no unusual problems from a reproduction standpoint.     

产羔期、补饲水平对考力代羊生产和繁殖性能影响的研究

为了研究草地一绵羊系统中草畜供求间的动态平衡，寻求在人工草地放牧条件下适宜的产羔时期及在此时期给产羔母羊的合理补饲水平，１９９０～１９９３年，在贵州省威宁县灼甫联户示范牧场进行了两期产羔期及补饲水平对绵羊生产性能影响的试验。产羔期的改变，导致了母羊及羔羊体重的不同变化趋势。结果显示出母羊体重对其生产、繁殖性能的重要性。春羔母羊配种前体重较之冬羔母羊提高９．７５ｋｇ，两者产羔率分别为１３９．２％和１１６．１％。春羔母羊较高的双羔率导致了春羔母羊较之冬羔母羊更低的繁殖成活率（分别为９１．２％和１０４．７％）。断奶时，春羔较之冬羔体重高５．２５ｋｇ，但断奶以后这种优势即消失了。补饲水平的差异对母羊及羔羊体重有一定的影响，但在牧草丰富的条件下表现得并不很强烈。     

Effects of supplementary feeding around lambing time on the productivity of Javanese thin-tail ewes

The extent to which ewe reproduction could be improved by supplementary feeding around lambing time was investigated with four groups each of 16 ewes which were run continuously with fertile rams until they had lambed three times. One group was fed at a maintenance level throughout and the other three groups were given supplementary feed during the last four week of each pregnancy only, or during the last four weeks of pregnancy plus the first six weeks after each lambing, or during the last four weeks of pregnancy plus the first 12 weeks after each lambing. The average body weight of lambs weaned at 13 weeks of age increased (P less than 0.001) progressively from 6.0 to 9.1 kg with increasing duration of supplementary feeding. There were however no significant differences between treatment groups in mean interval between successive lambings (202 days), ovulation rate (2.26), litter size (1.58), lamb birth weight (1.8 kg), preweaning lamb mortality (37%) or number of lambs weaned per lambing (0.99).     

放牧藏羊冷季营养调控试验报告

藏系绵羊在产羔后分为4组,进行为期90天的补饲试验,结果:试验1组只均日补饲优质青干草0.5 kg,母羊和羔羊的增重分别为1.57kg和5.29kg;试验2组只均日补饲精料0.25kg,母羊和羔羊的增重分别为2.36 kg和7.9kg;试验3组只均日补饲精料0.5kg,母羊和羔羊的增重分别为4.25 kg和10.02kg;试验4组只均日补饲营养添砖0.15kg,母羊和羔羊的增重分别为1.7kg和6.51kg。4个试验组均达到了母羊保膘和羔羊成活的目的。其中,第3组母羊和羔羊的增重最高,饲料成本也最高;第1组母羊和羔羊的增重最少,但补饲成本最低。     

Effect of season and lactation on postpartum fertility of Polypay, Dorset, St. Croix and Targhee ewes

The objective of this study was to compare rebreeding activities of spring- vs fall-lambing Polypay, Dorset, St. Croix and Targhee ewes that either suckled their lambs for 40 d or had lambs weaned at birth. Seasonal effects of male fertility were reduced by utilizing an excess number of fertile rams in the spring. Plasma concentrations of progesterone were monitored to assess days to the first normal ovulation, days to conception and estrous vs anestrous activity. Breed, season and lactation affected the rebreeding performance. Dorset ewes had similar conception rates between spring and fall but a shorter interval from lambing to first ovulation in the fall. Polypay and Targhee ewes were the opposite; they had higher conception rates in fall than in spring matings with no seasonal influence on postpartum interval. Postpartum ewes in the fall had higher conception rates, and fewer of these ewes became anestrous or had estrous cycles of abnormal duration than of those ewes lambing in the spring. Ewes that suckled for 40 d in the spring had delayed estrous activity, but when these ewes became estrual they had higher conception rates than ewes whose lambs were weaned at birth. Lactation had no inhibitory affect on the postpartum interval of fall lambing ewes. These data suggest that the response of different breeds to various components of postpartum fertility varies with season and management of the flock.     

Results of a crossbreeding experiment with sheep for different systems of fat lamb production. I. Reproductive traits

A crossbreeding experiment with sheep was carried out at two of the University's experimental stations between 1969 and 1973. On farm I ewes of five groups of different first crosses were tested against the indigenous purebred Merinoland sheep for five lambing periods. The ewes were kept under an accelerated lambing programme, the lambs were reared artificially. On farm II the same domestic breed was tested against three first cross lines with spring lambing and ewes suckling their lambs for 5 to 8 weeks. Each test group consisted of at least 50 ewes made up of 10 halfsib groups. 10 rams of each of four exotic fat lamb sire lines were hand-mated to the ewes. In addition, purebred and special control matings were carried out. All ewes in the experiment were of the same age.The data were analyzed by least squares procedures for different reproductive traits (gestation length, litter size for lambs born and reared, litter weight, score for lambing difficulties) and by simple one-way classifications for various others (lambs born and reared per ewe and year, lambing frequency, body weight, fleece weight, wool income).Since no significant interactions among main effects were detected for any trait, the presentation of the results emphasizes the general combining ability of the sire and dam lines. No significant differences were found between sire lines on both farms in all traits except gestation length. For the most important reproductive traits the differences between the dam lines were highly significant, the Finnish Landrace crosses being the best in both lambing frequency and number of lambs per litter. The superiority of these crosses cannot be maintained for the number of lambs reared and slaughtered, if, like in farm II, facilities are not available to rear lambs of large litters without high losses.     

Effects of sarcoptic mange on the reproductive performance of ewes and transmission of Sarcoptes scabiei to newborn lambs

In each of two experiments, the reproductive performance of ewes naturally infested with sarcoptic mange and of uninfested ewes was assessed in in-season natural breeding conditions (experiment I) or in out-of-season controlled breeding conditions (experiment II). A statistically significant difference was observed in the total lambs born per ewe (infested ewes, 1.2; controls, 1.6), in the liveborn lambs per ewe (infested ewes, 1.2; controls, 1.5) and in the lamb body weight per ewe (infested ewes, 3.33kg; controls, 4.53kg) under natural breeding conditions, as well as in the lamb body weight per ewe (infested ewes, 3.37kg; controls, 4.14kg) among ewes under controlled breeding conditions. No adverse effects were observed in the other reproductive indices, cycling rate, mating rate, return-to-oestrus rate, abortion rate, lambing rate and stillbirth rate. Sarcoptic mange was observed in the offspring of infested ewes after 30 days and in the offspring of uninfested controls 60 days after their birth.     

Lambing performance of Morlam and Dorset ewes under accelerated lambing systems

Two accelerated lambing systems, Morlam using Morlam sheep (USDA, Beltsville 1966 to 1975) and Camal using Dorset ewes (Cornell 1978 to 1981), were evaluated for first lambing ages, interlambing intervals and conception probabilities. Morlam ewes were continuously exposed to rams over the year, while Camal Dorset ewes were exposed every other month. Morlam lambs were mated as early as 367 d of age and Camal Dorset lambs as early as 340 d. Early lambing was associated with higher rates of perinatal mortality (P greater than .05) and smaller litter size (P less than .01). Lambing years among Morlam ewes and season of birth of Camal Dorset ewes influenced (P less than .01) their first lambing ages. Lambing intervals averaged 293 and 303 d among Morlam and Camal Dorset ewes, respectively. Age at first lambing and season in which the previous lambing occurred with influential factors (P less than .01) on lambing intervals of Morlam ewes; longer intervals resulted when ewe lambs were mated at early ages (less than 12 mo), and when the previous lambing occurred in winter. Estimates of conditional probabilities of conception by month given the occurrence of estrus, reflected seasonal changes in both systems. The overall probability of conception for the Morlam system (P = .16) was relatively higher than that for the Camal Dorset system (P = .14); numbers of lambings per ewe per yr were 1.28 and 1.21, respectively. Estimates of heritability for age at first lambing, lambing interval and conception probability were .31, .06 and .30, respectively.     

A comparison of Dorset and Finnish Landrace crossbred ewes

Data from 644 exposures and 552 lambings were used to analyze reproductive traits of 1/2-Finnish Landrace, 1/2-Dorset ewes (1/2 Finn); 1/4-Finnish Landrace, 3/4-Dorset ewes, (1/4 Finn) and Dorset ewes. Ewes were exposed to Hampshire or Suffolk rams for spring lambing from 1973 to 1978. The analytical model included fixed effects of ewe birth year (EBY), ewe breed (BR), lambing year within EBY and EBY X BR interaction and random effects of ewe within EBY and BR. Conception rate differed (P less than .01) for 1/2-Finn (.94), 1/4-Finn (.88) and Dorset (.80) ewes. Litter size was highest (P less than .01) for 1/2-Finns (1.97), followed by 1/4-Finns (1.74) and Dorsets (1.44). The 1/2-Finn ewes ranked first for number and weight of lambs weaned, and for number and weight marketed as feeder lambs. Birth weights were heavier (P less than .001) for lambs with Dorset dams (3.88 kg) than for lambs with 1/4-Finn (3.24 kg) or 1/2-Finn (3.08 kg) dams. Preweaning average daily gains and adjusted 90-d weights were also larger (P less than .001) for lambs with Dorset dams (.26 kg/d and 28.3 kg, respectively) than for lambs with 1/4-Finn (.24 kg/d and 25.4 kg) or 1/2-Finn (.24 kg/d and 25.1 kg) dams. However, Dorset ewes lambed an average of 10.5 d later than Finn-cross ewes, and actual weaning weights (unadjusted for age) did not differ significantly among lambs from Dorset (27.2 kg), 1/4-Finn (26.9 kg) and 1/2-Finn ewes (26.7 kg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of Ewe Performance in 795 Selected Sheep Flocks in South-Eastern Norway

A study of ewe performance was undertaken in 795 sheep flocks based on data from the Norwegian Sheep Recording System. Herd level data included in the annual report for 1998 were used as the basis for the study. Average flock size was 75.3 ewes. The material was considered as representative of the better and more motivated sheep farmers in the mountain valley regions in south-eastern Norway. The average number of lambs born per ewe, inclusive (and exclusive) of barren ewes, was 1.89 (2.02), and of autumn lambs (those surviving from birth in the spring to autumn) 1.60 (1.66). The average autumn weight of the lambs corrected to 145 days of age was 42.4 kg, giving an overall performance of 67.9 kg lambs live weight per ewe. When including artificially reared lambs, overall performance was 70.4 kg per ewe. Artificial rearing of lambs, mostly triplets which had been removed from the ewe, was practised on 395 of the farms. In the 74 flocks with a rate of artificial rearing of more than 10% of all lambs, overall performance per ewe was 13.3 kg higher than in flocks with no artificial rearing. Total lamb mortality from birth to autumn recording, including stillborn lambs, was 12.44%. Mortality had a skewed distribution, some flocks having very high mortality figures. The arithmetic means (and medians) for mortality were as follows: 2.75 (2.29)% stillbirths, 2.93 (2.30)% died during the indoor feeding period, 0.88 (0.00)% at spring pasture, and 6.16 (4.40)% at summer pasture. In regression models using Proc Genmod in SAS^®, it was found that average number of autumn lambs per ewe was negatively associated with the rate of barren ewes, late lambing date (flock average day in year when lambing took place), and total lamb mortality. The corrected autumn weight of the lambs was positively associated with the average number of lambs born per ewe and non-fertility rate, and negatively associated with flock size and total lamb mortality. The Dala breed had a positive effect on number of autumn lambs per ewe, and Spæl breed a negative effect on corrected autumn live weight of the lambs.