Onset of puberty and duration of the breeding season in Suffolk, Rambouillet, Finnish Landrace, Dorset and Finn-Dorset ewe lambs

Sixty ewe lambs, 12 each of Suffolk, Dorset, Finnish Landrace, Finn-Dorset and Rambouillet born in January and February were used in a study of puberty and duration of the first breeding season. Ovulation was monitored via progesterone assay of weekly blood samples beginning in July, and estrus via daily checking with vasectomized rams. All 60 ewes ovulated but three, one Dorset and two Rambouillet failed to show estrus although each had five to seven ovulatory cycles. Several ewes showed small progesterone rises, 300 to 500 pg/ml, before first ovulation and six (10%) failed to initiate regular cyclicity following the first ovulation as defined by progesterone greater than 500 pg/ml. Mean number of ovulatory events before the first behavioral estrus ranged from 1.25 for Finnish Landrace to 2.20 for Rambouillet ewe lambs (P less than .1). Rambouillets were older (277 d; P less than .05) at first estrus than Finns (258 d) and Finn-Dorsets (260 d), but differences in age at first ovulation were not significant: Finn-Dorset, 233 d; Dorset, 234 d; Finn, 235 d; Rambouillet, 240 d; Suffolk, 245 d. Most cycles were of normal length, with 91.4% between 14 and 20 d. Repeatability of cycle length within breed group was .38. Suffolks had significantly shorter cycles (16.1 d) than the other four groups (17.0 to 17.4 d). Finnish Landrace and Finn-Dorset ewes continued to cycle much longer than the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

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)     

Reproductive performance of Suffolk and Suffolk-cross ewes and ewe lambs exposed to vasectomized rams before breeding

Multiparous Suffolk and Suffolk-cross ewes were randomly allotted to treatments within breed and year to measure effects of ram exposure, during transition from anestrus to breeding activity, on reproductive performance. Treatments were: 1) ewes joined with two mature vasectomized Rambouillet rams for 15 d before breeding (DC), 2) ewes maintained across a net wire fence from two vasectomized rams for 15 d before breeding (FC) and 3) ewes maintained approximately 400 m away from rams (NC). At the end of the 15 d, all ewes were placed in one pasture and mated to three fertile Suffolk rams during a 34-d breeding season. A total of 96 Suffolk and 177 Suffolk-cross ewes was utilized during the 3-yr experiment. A greater (P less than .05) prebreeding ovulation percentage was observed in DC and FC than in NC ewes. Mating and lambing occurred approximately 6 d earlier for DC or FC ewes than for NC ewes. A similarly designed experiment was conducted using Suffolk and Suffolk-cross ewe lambs allotted to treatments within breed and year to measure effects of ram exposure during the natural breeding season, but prior to breeding. Treatment differences were not detected (P greater than .05) for date of first observed estrus, date of lambing, percentage of ewes lambing in the first 17 d of the lambing season, number of lambs born per ewe lamb exposed or number of lambs born per ewe lamb giving birth.     

Straightbred comparison of a composite population and the Suffolk breed for performance traits of sheep

A terminal sire Composite population was formed by mating Columbia rams to Hampshire-Suffolk crossbred ewes. Subsequent generations were produced by inter se mating. The objective was to compare Composite sheep to purebred Suffolks for numerous performance traits. Young ewes lambing at 1 yr of age were evaluated separately from mature ewes (2, 3, 4, and 5 yr old) of each population. Composite and Suffolk populations did not differ significantly in components of litter weaning weight per young ewe joined. Mature Composite ewes produced more wool than Suffolk ewes. Fertility of mature ewes did not differ significantly between populations. The greater prolificacy (P less than .01) of mature Suffolk ewes was offset by a lower survival to weaning (P less than .01), particularly for twin-born lambs. Consequently, mature Composite and Suffolk ewes did not differ for number weaned and litter weaning weight per ewe joined. The average birth weight of lambs born to young and mature Composite ewes was greater (P less than .02) than the average birth weight of Suffolk lambs. The average weaning weight of lambs born to young Composite ewes was greater (P less than .05) than that of lambs born to young Suffolk ewes. Breed differences were not detected for preweaning daily gains, weaning weights, and postweaning daily gains of ewe lambs born to mature ewes. Likewise, weights of ewes at 125 d of age and weights of mature ewes at breeding did not differ significantly between breeds.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of colostrum in glomerulonephritis of Finnish Landrace lambs: effect of cross-fostering newly born Finnish Landrace and Cheviot lambs.

Newly-born Finnish Landrace and Cheviot lambs were cross-fostered to determine the role of colostrum in the development of mesangiocapillary glomerulonephritis of the Finnish Landrace breed. Severe glomerulonephritis occurred in four Finnish Landrace lambs reared by their own dams. One of six siblings of affected lambs, all reared by Cheviot foster mothers, developed a milder focal form of the disease. No glomerulonephritis occurred in three Cheviot lambs reared by Finnish Landrace foster mothers whose own naturally reared lambs died of the disease. An artificially reared colostrum-free Finnish Landrace lamb became severely affected, though its naturally reared sibling had no renal disease in sequential biopsies. It is concluded that colostrum has no primary role in the development of the disease.     

白萨福克羔羊和特克塞尔羔羊早期生长发育的比较研究

试验对白萨福克羊(White Suffolk)和特克塞尔羊(Texel)两个肉羊品种的羔羊在6月龄以前的生长发育进行了比较研究。结果表明:白萨福克羔羊和特克塞尔羔羊初生重大,除白萨福克母羔外,其余羔羊初生重都在5 kg以上,其中白萨福克公羔的初生重最大;4月龄时,白萨福克公羔体重达到32.88 kg,显著高于特克塞尔公羔(P<0.05),极显著地高于特克塞尔母羔(P<0.01);6月龄时白萨福克公羔体重达到42.60 kg。白萨福克羔羊2月龄时的绝对生长速度最大,公羔日增重达到256.15 g,母羔达到236.67 g;特克塞尔羊从出生到1月龄,绝对生长和相对生长比白萨福克羊要高一些,但是白萨福克羊保持快速生长发育的持续期较特克塞尔羊相对较长。白萨福克羔羊从母乳到饲草饲料过渡较好,断奶后适应性要好于特克塞尔羔羊,从4月龄到6月龄的体重、体尺高于特克塞尔羔羊。在整个测定阶段,白萨福克公羔和母羔的体躯均比特克塞尔公羔和母羔的体躯长,白萨福克公羔体高比特克塞尔公羔的体高要高。     

Extent of linkage disequilibrium and effective population size in Finnish Landrace and Finnish Yorkshire pig breeds

The extent of linkage disequilibrium (LD) and effective population size in Finnish Landrace and Finnish Yorkshire pig populations were studied using a whole genome SNP panel (Illumina PorcineSNP60 BeadChip) and pedigree data. Genotypic data included 86 Finnish Landrace and 32 Finnish Yorkshire boars. Pedigree data included 608,138 Finnish Landrace 554,237 and Finnish Yorkshire pigs, and on average 15 ancestral generations were known for the reference animals, born in 2005 to 2009. The breeding animals of the 2 populations have been kept separate in the breeding programs. Based on the pedigree data, the current effective population size for Finnish Landrace is 91 and for Finnish Yorkshire 61. Linkage disequilibrium measures (D' and r(2)) were estimated for over 1.5 million pairs of SNP. Average r(2) for SNP 30 kb apart was 0.47 and 0.49 and for SNP 5 Mb apart 0.09 and 0.12 for Finnish Landrace and Finnish Yorkshire, respectively. Average LD (r(2)) between adjacent SNP in the Illumina PorcineSNP60 BeadChip was 0.43 (57% of the adjacent SNP pairs had r(2) > 0.2) for Finnish Landrace and 0.46 (60% of the adjacent SNP pairs had r(2) > 0.2) for Finnish Yorkshire, and average r(2) > 0.2 extended to 1.0 and 1.5 Mb for Finnish Landrace and Finnish Yorkshire, respectively. Effective population size estimates based on the decay of r(2) with distance were similar to those based on the pedigree data: 80 and 55 for Finnish Landrace and Finnish Yorkshire, respectively. Thus, the results indicate that the effective population size of Finnish Yorkshire is smaller than of Finnish Landrace and has a clear effect on the extent of LD. The current effective population size of both breeds is above the recommended minimum of 50 but may get smaller than that in the near future, if no action is taken to balance the inbreeding rate and selection response. Because a moderate level of LD extends over a long distance, selection based on whole genome SNP markers (genomic selection) is expected to be efficient for both breeds.     

陶赛特羊、萨福克羊与藏羊杂交改良试验研究

陶赛特羊原产于澳大利亚和新西兰,具有早熟、生长发育快、胴体品质好、适应性强、繁殖率高和耐粗饲等特点,是肉羊生产的理想品种之一.     

Heritage Finnish Landrace chickens are genetically diverse and geographically structured

ABSTRACT

The Finnish Landrace breed of chickens (in Finnish suomalainen maatiaiskana) traces its origins to almost 1,000 years ago. Today, remnant populations of phenotypically distinct lineages are maintained by a network of volunteer hobbyists in Finland, managed by Natural Resources Institute Finland (Luke). Guided by a prior Major Histocompatibility Complex B-locus haplotype study, we sought now to characterize genetically Finnish Landrace chickens using denser genomic sampling. A new panel of 101 selectively neutral SNP sites was used to interrogate genetic variation in 192 individuals sampled from 13 putatively distinctive population units. Individuals partitioned into K?=?11 genetic clusters characterized by high levels of genetic diversity, strong patterns of genetic structure and low levels of inbreeding. Evidence of an undocumented genetic lineage was also discovered. Facilitated by an inexpensive SNP assay, this study shows that the genetic integrity of the Finnish Landrace persists and represents a rich resource of natural (adaptive) genomic variation.     

Experimental infection of fetal and newborn Suffolk sheep with scrapie virus

Fetal (n = 21) and newborn (n = 7) Suffolk sheep were inoculated with scrapie virus isolated from other Suffolk sheep. Twenty fetuses, 76 to 109 days of gestational age, were inoculated IM in the neck through the uterine wall and were examined for virus 47 to 322 days later by mouse inoculation. Scrapie virus was not detected before 254 days of age; only traces of virus were detected in 3 of 7 lambs examined thereafter (2 at 254 days of age and 1 at 322 days of age). Virus was limited to the supra-pharyngeal, prescapular, and mesenteric lymph nodes. Seven lambs were inoculated into the palatine tonsils with scrapie virus as newborns (3 to 12 days old) and were examined for virus when they were 147 to 210 days old. Virus was not detected in the lymphoreticular tissues or terminal portion of ileum of any lamb. Failure to find scrapie virus in these lambs and in most lambs inoculated as fetuses might indicate few had became infected. However, if most lambs and fetuses had become infected, the long zero phase of the infection could have accounted for failure to find scrapie virus in many of them examined too soon after inoculation. The limited findings of this study indicate that efforts to demonstrate prenatal or neonatal transmission of scrapie by detecting virus are hampered by the slowness of its replication.     

Effectiveness of photoperiod stimulation on reproductive performance of sheep housed continuously indoors on an accelerated breeding schedule.

Over five breeding periods, the reproductive performance (fertility, prolificacy and fecundity) of three strains of sheep housed continuously indoors was measured. The sheep were maintained as two separate flocks, A and B, with similar genetic background on an eight month accelerated breeding schedule under one of three lighting regimes, abrupt, contracted or constant, to induce ovarian activity. Overall fertility to one estrus was 59%. For flock A, fertility was greatest under the contracted lighting regime and lowest under the constant lighting regime; the opposite was true for flock B. Among the three strains, fertility was lowest for the Dam 2 strain in flock A. Prolificacy averaged 1.8 lambs per ewe lambing and was similar under each of the three lighting regimes. Fecundity (averaging 106%), the number of lambs born per 100 ewes exposed to rams, generally followed the pattern of fertility.     

不同激素组合对萨福克绵羊超数排卵的影响

家畜胚胎移植过程中,供体、受体的同期发情处理以及超数排卵会对胚胎移植的效果产生显著影响。以萨福克绵羊为供体,小尾寒羊为受体,比较加拿大产的Folltropin-V与国产FSH组合用药对萨福克绵羊同期发情和超数排卵的效果。结果表明:采用加拿大产Folltropin-V的平均黄体数为1072枚,平均可用胚胎数为657枚;而国产FSH混合用药的平均黄体数为1018枚,平均可用胚胎数为647枚,两者效果未见显著差异。     

情宝与外源激素对长白母猪繁殖性能的影响

为研究中药催情药以及外源性生殖激素对母猪繁殖性能的影响,试验利用中药催情药情宝以及外源生殖激素氯前列烯醇（PG）和促排卵素三号（LRH-A3）,对某猪场的48头纯种长白母猪进行催情试验。结果表明,情宝＋氯前列烯醇＋LRH-A3的催情效果最佳,其次是情宝＋LRH-A3以及情宝＋氯前列烯醇,而氯前列烯醇＋LRH-A3的效果最小。     

Reproductive efficiency of Iceland sheep

Iceland sheep are found to be relatively early maturing and the level of reproductive efficiency in the flock is raised by breeding from ewe lambs. Ram lambs are normally used for mating. Ewe prolificacy is progressively being increased by genetic selection for a higher lambing rate in conjunction with improvements in feeding. Lamb mortality is kept at a relatively low level by close supervision at lambing and disease control.     

萨福克羊与青海毛肉兼用细毛羊杂交试验

以著名肉羊品种萨福克为父本,以青海毛肉兼用细毛羊为母本,进行杂交对比试验,结果表明:试验组初生重、6月龄体重、周岁胸宽、后躯宽、体斜长、和5月龄胴体重、净肉重、肉骨比分别比对照组提高了2.57%、19.74%、9.20%、6.24%、和10.30%、45.6%、16.56%,杂交效果非常明显。     

萨福克羊与宁夏土种绵羊杂一代育肥试验

试验结果表明，萨杂F1羊的初生重，3月龄和6月龄的体重均显著高于土种羊（P＜0．01），经育肥的8－9月龄阉羊屠宰测定表明，F1的宰前活重，胴体重和净肉重分别为35．80kg,18.34kg和14．40kg，均显著高于土种羊（P＜0．01），屠宰率为51．23％，胴体净肉率为78．52％，眼肌面积15．20cm2，骨肉比为1．0：5．17，均优于土种羊，每只杂种羊比土种羊增收75．40元。     

Serum and cerebrospinal fluid concentrations of immunoglobulin G in Suffolk sheep with scrapie

Determinations were made by laser nephelometry of serum and CSF immunoglobulin (Ig) G concentrations in Suffolk sheep with naturally occurring scrapie. The serum IgG concentrations in 3 sheep with confirmed or suspected scrapie were between 2,140 and 3,290 mg of IgG/100 ml, and the CSF values were between less than 10 and 75 mg of IgG/100 ml. In 8 clinically healthy (control) sheep, serum IgG concentrations were 2,647 to 7,380 mg/100 ml and CSF IgG concentrations were between 0 (undetectable) and 162 mg/100 ml. A sheep with pulmonary adenomatosis had 1,445 mg of IgG/100 ml of serum. The results indicated that neither serum nor CSF IgG concentrations were increased in sheep with naturally occurring infection with scrapie and that the severity of the disease did not correspond with the IgG concentration.     

丹系长白猪繁殖性状表型参数与选择指数的研究

通过对丹系长白猪繁殖性状的统计分析，比较各相关指数，找出性状间相关程度，对初生窝仔猪数，20日龄窝重及断奶窝仔猪数求出相应选择指数，为猪育种工作提供依据。