Lambing Rate Research Articles

Determination of fertility traits of sheep and growth characteristics of Chios crossbred male lambs reared under local breeder conditions

This study was conducted to determine the fertility of Chios x Kıvırcık and Chios x Cine Caparı crossbreed sheep (94 ewes) and the growth characteristics and liveability values of crossbred lambs (62 male kids) under local breeder conditions. The birth and lamb rate and litter size values of Chios x Kıvırcık ewes and Chios x Cine Caparı ewes were detected as 93%, 1.21 and 1.29; 93%, 1.12 and 1.20. respectively. The liveability traits of crossbred lamb for each genotype on the 120th day of age were 81.06% and 84.00%, respectively. The average live weights on birth and 120th day of age were detected as 3.97 kg and 26.89 kg; 3.86 kg and 25.86 kg, respectively. For the same periods, the average of body measurements such as height at withers, rump height, body length and chest girth were detected as 38.08 cm, 38.27 cm, 35.79 cm and 37.76 cm; 59.67 cm, 59.61 cm, 57.18 cm and 74.71 cm respectively for Chios x Kıvırcık lambs and also determined as 37.18 cm, 37.49 cm, 35.36 cm and 36.59 cm; 59.44 cm, 59.30 cm, 56.68 cm and 74.43 cm, respectively for Chios x Cine Caparı lambs. While flocks had an statistically significant effect in generally on all growth periods, except birth; differences between genotypes were statistically significant for the last two measurement periods. It was thought that the animals having higher production levels and also adaptability could be reared in the region with suitable management, breeding and crossbreding systems.

The influence of birth type and sex on rearing of Polish Heath and Żelaźnieńska lambs

<b>The aim of the study was to determine the effect of birth type and sex on lambs survival parameters of polish heath and żelazneńska sheep. The research included data, which was used to determine the prolificacy index, the percentage of live-born lambs and the lambs rearing index up to 100 days of age. A higher prolificacy index (P≤0.01) and a higher percentage (P≤0.01) of reared lambs were determined in the polish heath compared to the żelazneńska sheep. In the herd of the first breed, a greater proportion of twin and more numerous litters than singleton births were noted. Single and twin litters were dominant in the żelazneńskie sheep. The rearing rate of lambs from single litters was at a similar level in both observed breeds. However, in the herd of polish heath sheep, lambs from multiple litters shoved also high rearing rate. Single ram lambs were characterized by higher (P≤0.01) body weight at birth and at 56 days of age compared to twin born and ewe lambs, both in polish heath sheep and żelazneńska sheep. Statistical differences (P≤0.01) in body weight at birth and on 56th day of age were also recorded between twins and triplets in polish heath sheep. The analysis of the distribution of lambs' mortality during the rearing period has shown that the most critical is the first week of life of the born offsprings.</b>

Effect of maternal haemoglobin variants and lamb genotype on pre-weaning growth rate of sheep of Northern Nigerian and their crosses


 
 
 
 Pre-weaning growth trait of sheep of Northern Nigerian (Balami, Uda and Yankasa) subjected to diallel crossing were estimated using 127 lambs. The study was conducted at National Animal Production Research Institute (NAPRI), Zaria, Nigeria. Blood (5ml) samples were collected from ewes and rams that produce the lambs to evaluate the effect of parental haemoglobin (Hb) variant on the pre-weaning growth rate of lambs. Weight and average daily gain (ADG) of lambs were obtained at 2 weeks interval to 12th week. The data obtained were subjected to analysis of variance using General Linear Model Procedure of SAS. Pair-wise difference was used to separate the mean. Frequency of ewes’ Hb genotype in relation to lambs was sorted and tested with Chi Square Procedure of SAS. The result showed that HbAB was the predominant (P<0.01) variant in the studied population, observed in 60% of the ewes and 100% of the sires. Allele A had the highest frequency (62%) in the dam population. The genotypic distribution of Hb variants in the population significantly deviated from Hardy Weinberg equilibrium (χ2 = 50.8, P<0.01). HbAB and HbBB dams gave birth to lambs that were heavier (P<0.01) than lambs from HbAA from birth to 12 weeks of age. Crossbred lambs from Balami rams and Uda ewes (BL x UD) recorded the highest weight (4.47±0.20 kg) at birth while the least weight (1.73±0.20 kg) at birth was obtained from crossbred lambs given birth to by Yankasa rams and Balami ewes (YK X BL). Pure Balami lambs (BL X BL) was outstandingly superior (P<0.05) to lambs from other genotypes starting from the second week of age up to weaning (12th week). BL X BL also recorded the highest (238.09±12.42 g) average daily gain from birth to 2 weeks of age (ADG2). The ADG decreased linearly as the lambs advanced in age from birth to weaning. Balami sheep are capable of expressing their genetic potentials (better growth than others) in the Northern Guinea Savannah zone of Nigeria. Genetic improvement of growth traits of Nigerian sheep using indigenous stock should focus on the exploitation of genetic potentials in terms of faster growth rate of Balami sheep.
 
 
 

Sivas İli Yetiştirici Koşullarındaki Kangal Akkaraman Koyunlarda Dölverimi Özellikleri

Hayvan yetiştiriciliğinde anaç sürüden elde edilen yavru sayısı veya oranı olarak ifade edilebilen dölverimi, başarılı bir yetiştiriciliğin ilk koşuludur. Bu araştırmada, Tarım ve Orman Bakanlığınca Halk Elinde Hayvan Islahı Ülkesel Projesi kapsamında yürütülen çalışmalara dâhil Sivas Merkez ve Yıldızeli ilçelerinde yer alan iki alt projenin (58KAK2012-06 ve 58KAK2012-07), 2013 ila 2018 yılları arası altı yıllık verilerinden yararlanılarak, Kangal Akkaraman ırkı koyunların dölverimi özelliklerinin belirlenmesi amaçlanmıştır. Çalışmada ilk yıl, projeye dahil her iki ilçeden toplam 48 köydeki 70 işletme, altıncı yılda 33 köyde 57 işletmeye düşmüştür. Altı yıllık süreçte, ıslah projesindeki tüm işletmelerdeki toplam 76383 anaç koyundan elde edilen 86116 kuzu kaydı değerlendirilmiştir. Alınan tüm verilere göre ortalama doğum oranı %92.7 olurken yıllar arası farklılıklar istatistiki olarak önemli, ilçeler arası farklılıklar ise önemsiz bulunmuştur. Çalışmada elde edilen veri sayısı çok fazla olduğundan, üçüz doğumlara da rastlanmış ancak çok düşük oranda (ortalama %0,1) kalmasından dolayı ayrıca değerlendirilmeyip, ikiz doğumlara dahil edilmiştir. Elde edilen tüm değerlere göre ortalama ikiz doğum oranı %22 olurken, yıllar arası, ilçeler arası ve koç katım dönemleri arası (ağustos-aralık ayları arası beş ay) farklılıklar önemli bulunmuştur. Yine dölverimi ölçütlerinden sütten kesilen kuzu oranı ya da sütten kesim dönemi yaşama gücüne ait genel ortalama %91,3 olurken, yıllara, ilçelere ve kuzu doğum zamanına (ocak-mayıs ayları arası beş ay) göre farklılıklar istatistiki olarak önemli bulunmuştur. Çalışmada ana yaşı bilinen, sadece 2013 yılına ait bir alt projedeki 4242 koyundan elde edilen 5147 kuzu kaydına göre, koyunların yaşı (1-10 arası) doğum tipi üzerinde etkili bulunurken, yaşama gücü üzerinde istatistiki olarak önemsiz bulunmuştur. Araştırma sonuçlarına göre çalışma bölgesinde ve benzer şartlara sahip işletmelerde karlılığı en üst düzeye çıkarmak için dölverimini artıran faktörlerin dikkate alınması yararlı olacaktır.

Infectious Diseases, Livestock, and Climate: A Vicious Cycle?

Ruminant livestock are a significant contributor to global methane emissions. Infectious diseases have the potential to exacerbate these contributions by elevating methane outputs associated with animal production. With the increasing spread of many infectious diseases, the emergence of a vicious climate–livestock–disease cycle is a looming threat.

Effects of parenteral administration of tylosin and ivermectin on abomasal emptying rate in healthy suckling lambs by use of nuclear scintigraphy

Abomasal hypomotility is one of the important causes of neonatal mortality in small ruminants. Various pharmaceutical agents have been studied to address this problem in large ruminants. The aim of this study was to determine the effect of parenteral administration of tylosin and ivermectin on abomasal emptying rate in neonatal suckling lambs. Abomasal emptying rate was assessed using nuclear scintigraphic method in 10 healthy female Iranian fat tailed Ghezel lambs. Each lamb was tested three times, once as a control (1 ml of saline 0.9%, IM) and twice after the injection of tylosin (17.6 mg/kg, IM) and ivermectin (200 μg/kg, SC) in a crossover study. Based on radiopharmaceutical counts, remnant activity in abomasums at 90 min were 48.3 ± 3.5, 45.6 ± 7.5 and 41.6 ± 2.9% in control, tylosin and ivermectin groups, respectively. Administration of tylosin (p = 0.049) and ivermectin (p = 0.045) to lambs, significantly caused faster abomasal emptying rate compared to control. Evaluating the ROIs revealed that the half emptying time (T1/2) in control, tylosin and ivermectin groups were 67.1 ± 8.6, 62.6 ± 14.2 and 54.3 ± 9.9 min, respectively. These difference between all groups, statistically were significant (p = 0.026). However, the clinical efficacy of abomasal emptying rate facilitating by tylosin or ivermectin administration in lambs remains to be determined.

Multiple omics analysis reveals that high fiber diets promote gluconeogenesis and inhibit glycolysis in muscle

BackgroundMeat quality is a complex trait affected by genotypic and environmental factors. In a previous study, it was found that feedstuffs have various effects on the growth rate and meat quality of lambs. However, the underlying mechanisms are still not entirely clear.ResultsIn this study, to investigate the mechanisms that impact meat quality in twin sheep fed either with high fiber low protein (HFLP) forage (Ceratoides) or low fiber high protein (LFHP) forage (alfalfa) diets, multi omics techniques were utilized for integration analysis based on the feed nutritional value and the sheep microbiome, transcriptome, metabolome, and fatty acid profile. Results showed that the production performance and the muscle components of lambs were significantly affected by feeds. The essential fatty acid (linoleic acid and arachidonic acid) content of the muscle, based on gas chromatography-mass spectrometry analysis, was increased when lambs were fed with HFLP. The microbes in the lambs’ rumen fed a HFLP diet were more diverse than those of the LFHP fed group. Besides, the ratio of Bacteroidetes and Firmicutes in the rumen of the sheep fed a LFHP diet was 2.6 times higher than that of the HFLP fed group. Transcriptome analysis of the muscle revealed that the genes related to glucose metabolic processes and fatty acid biosynthesis were significantly differentially expressed between the two groups. Potential cross talk was found between the sfour omics data layers, which helps to understand the mechanism by which feedstuffs affect meat quality of lambs.ConclusionFeed systems may affect the epigenetic regulation of genes involved in the glucose metabolic pathway. HFLP feeds could induce gluconeogenesis to maintain glucose levels in blood, resulting in decreased fat content in muscle. The multiple omics analysis showed that the microbiota structure is significantly correlated with the metabolome and gene expression in muscle. This study laid a theoretical foundation for controlling the nutrient intake of sheep; it suggested that its fatty acid spectrum modifications and the removal of meat quality detrimental material could guide sheep feeding for functional mutton.

The effect of a perennial wheat and lucerne biculture diet on feed intake, growth rate and carcass characteristics of Australian lambs

A pen feeding study was conducted using 10 month old Poll Dorset × Merino ewe lambs to test the effect of perennial wheat forage on growth rates and carcass characteristics in comparison to annual wheat forage. Individual lambs (n = 48) were fed one of four diets, namely perennial wheat (PW), annual wheat (W), perennial wheat + lucerne (alfalfa) (PW + L) or annual wheat + lucerne (W + L). Lambs were monitored for 28 days during which daily forage quality, forage mineral content, feed intake and weekly liveweight change were recorded. At the completion of the feeding period all lambs were slaughtered in a commercial abattoir. At 24 h post-slaughter the left hand side longissimus lumborum muscle (LL) was removed and assessed for quality attributes. Feed intake increased over the 28 days with W fed lambs eating a greater amount compared to PW fed lambs. The addition of lucerne to the cereal forage (PW + L and W + L) increased feed intake (P < 0.001) of the lambs. However, there were no independent dietary effects on liveweight, carcass weight, carcass traits, including yield parameters, pH declines or fresh colorimetrics. Both the W and PW diets had potassium (K) concentrations greater than 3%. Sodium (Na) deficiency was greater in the PW diet. This indicated that lambs fed these diets would be exposed to impaired calcium (Ca) metabolism and reduced magnesium (Mg) absorption. The addition of lucerne to both cereal forages increased the intake of Ca and Mg and lowered the tetany index. Preferential selection of lucerne was observed in lambs fed the PW + L diet compared to those fed W + L. However, the Na deficiency was not resolved by the addition of lucerne and the dietary cation-anion difference (DCAD) remained high for all diets. Low Na content and consequential effects of a high K:Na + Mg ratio may have limited the expression of higher growth rates (range 55–110 g per day) from the different diets offered. The high DCAD implies calcium homeostasis would be challenged by all diets. This study establishes the value of perennial wheat as a novel forage source as there were no unfavorable effects on lamb carcass parameters, however the mineral imbalances in the forage would need to be managed in the same way as they are presently managed in grazing systems using dual-purpose annual wheat.

The Effect of Oral Administration of Turmeric (Curcuma longa) Aqueous Extract on Abomasal Emptying Rate in Neonatal Lambs

زمینۀ مطالعه: کاهش حرکات شیردان نقش مهمی در بیماریزایی برخی اختلالات شیردانی همچون نفخ شیردان ایفاء می‌کند که درمان آن با داروهای سنتتیک عوارضی مانند اسهال و مقاومت آنتی‌بیوتیکی دارد و تجویز داروهای گیاهی راهکار مناسبی برای کاهش این عوارض جانبی است. هدف: تعیین اثر تجویز خوراکی عصاره آبی زرد چوبه برسرعت تخلیه شیردان در بره‌های نوزاد. روش‌کار: این مطالعه بر روی 12 بره ماده پنج روزه نژاد سنگسری انجام گرفت (میانگین وزن 3کیلوگرم). همه بره‌ها به ترتیب پنج درمان خوراکی شامل سالین (30میلی‌لیتر)، اریترومایسین (400میلی‌گرم)، زردچوبه 200 میلی‌گرم بر کیلوگرم، زردچوبه 250میلی‌گرم بر کیلوگرم و زردچوبه 300 میلی‌گرم بر کیلوگرم را دریافت کردند. در دقایق صفر30،60،،120، 150، 180 و 240 پس از هر درمان نمونه پلاسما از بره‌ها اخذ گردید و با استفاده از تست جذب استامینوفن سرعت تخلیه شیردان تعیین شد. نتایج: درمان با اریترومایسین و سه دز متفاوت عصاره آبی زردچوبه (200، 250 و 300 میلی‌گرم بر کیلوگرم) نسبت به درمان کنترل منفی سبب افزایش معنی‌دار سرعت تخلیه شیردان گردید (05/0>P). اثر تحریکی اریترومایسین در تخلیه شیردان به صورت معنی‌داری از عصاره آبی زردچوبه بیشتر بود (05/0>P). هیچ گونه عارضه جانبی‌ بالینی به دنبال تجویز اریترومایسین و زردچوبه در بره‌ها مشاهده نشد. نتیجه‌گیری نهایی: این پژوهش نشان داد که عصاره‌ی آبی زردچوبه اثر تحریکی بر تخلیه شیردان بره دارد اما به مطالعات بیشتری درزمینه‌ی اثر اجزای این گیاه بر تخلیه شیردان نیاز است.

Effect of grazing different forage systems prior to and during mating on the liveweight, condition score, conception and reproductive rate of maternal-composite ewe lambs

Context Economic modelling identified that mating of ewe lambs for lambing at 1 year of age has the potential to increase the profitability of sheep-production systems in south-western Victoria. In order to optimise reproductive rates, ewe lambs should weigh at least 35–40 kg, have a condition score (CS) of 3.0 at mating, and be gaining weight (100–150 g/day) during mating. However, typical perennial ryegrass (Lolium perenne L.) pastures in south-west Victoria do not support the attainment of these targets without additional supplementation. Aim Our research aimed to determine how grazing summer-active pastures or brassica (Brassica napus L.) forages affects the liveweight, CS, conception and reproductive rate of ewe lambs when offered before and during mating compared with a system using perennial ryegrass plus supplement. Methods A field experiment was conducted at Hamilton, Victoria, Australia, in 2014 and 2016 testing seven forage treatments replicated four times in a complete block design. The treatments were: canola (B. napus, two treatments of different cultivars), forage brassica, lucerne (Medicago sativa L.), chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.) and perennial ryegrass. Key results Ewe lambs grazing canola or forage brassica had higher (P &lt; 0.05) liveweight gains during the pre-mating and mating periods than those grazing the perennial ryegrass treatment (148 vs 75 g/day in 2014, s.e.m. 17; 139 vs 54 g/day in 2016, s.e.m. 17). In 2014, spring-sown dual-purpose canola, lucerne and chicory resulted in higher (P &lt; 0.05) reproductive rates (144–151%) than the perennial ryegrass treatment (103%); forage brassica and plantain gave intermediate results (128% and 129%). Conclusion Brassica forages (including spring-sown canola), lucerne and chicory can support the attainment of key liveweight and CS targets for successful mating of ewe lambs in autumn. Implications Spring-sown canola is therefore a viable alternative forage for use by livestock producers in southern Australia and presents an opportunity to incorporate an alternative income stream in mixed-farming systems.

Biological responses of hair sheep to a permanent shade during a short heat stress exposure in an arid region

Abstract Summer heat stress (HS) in warm climates decreases feedlot performance and, in extreme cases, causes death in fattening lambs. A traditional strategy to mitigate effects of HS has been the installation of galvanized sheet metal shades that partially or totally cover the corrals; however, the impact of total shading on thermoregulation and growth in hair lambs has been little studied. Twenty Dorper × Pelibuey ewe lambs were assigned to two treatments (n = 10; non-shaded vs. shaded) for two weeks to evaluate the effects of providing total shading with galvanized sheet metal in the fattening corral on physiological variables, blood analyte concentrations and growth performance under HS conditions in an arid region. Rectal temperature and respiratory rate in shaded ewe lambs were higher at 0600 h and lower at 1200 and 1800 h compared to non-shaded ewe lambs. Shaded ewe lambs had lower serum levels of glucose, cholesterol, triglycerides, K+ and Cl−, but higher serum urea levels, compared to non-shaded ewe lambs. Additionally, most of the mean values of hematological variables were higher in shaded ewe lambs versus non-shaded. Shaded ewe lambs had higher feed intake but similar growth rate and water intake than its counterpart. In conclusion, under summer HS conditions in an arid region, the thermoregulatory capacity of hair ewe lambs is improved during the daytime but compromised in the nighttime by completely shading the feedlots with galvanized sheet metal. Additionally, the lack of protection against solar radiation negatively affected feed intake and energy metabolism.

Survival analysis and reproductive performance of Dorper x Tumele sheep

Productivity and profitability of sheep farming are highly influenced by lamb survival and ewe reproductive performance. Thus, this study was conducted to evaluate the survival and reproductive performance of crossbred sheep. Data collected from 2009 to 2018 from Sirinka sheep breeding stations were utilized for this study. Survival analysis was conducted by using Survival Kit 6.12 software with the Weibull model and the general linear model of SAS 9.0 was used to analyze reproductive traits. The overall mean survival rate of Dorper x Tumele crossbred lambs at 3, 6 and 12 months of age were 86.0, 76.6, and 67.9%, respectively. About 46.8% of mortality from the total death was observed during the first 120 days of life. Gastrointestinal parasites, pneumonia and septicemia were the major causes of lamb mortality. Birth weight, birth type, sex and year of lambing were the most important risk factors for survival of crossbred lambs. The overall least-squares means for litter size at birth, litter size at weaning, total litter weight at birth and total litter weight at weaning were 1.10 lambs, 0.94 lambs, 3.28 kg and 15.5 kg, respectively. Birth type, sex and year of lambing were the most determinants of ewe productive traits. Tumele and their crossbred sheep had good mothering ability necessary to successfully raise lambs to weaning. The current crossbreeding program which aims to improving growth performance had a positive influence on the survival rate of lambs. Improvement of environmental in the flock, special care for small lambs and indirect selection based on birth weight would lead to further survival improvement.

Milk yield and composition from ewes fed diets containing narasin and their lambs' performance.

The changes promoted by feed additives in ruminal fermentation, especially increasing the availability of propionate, can improve the energy balance of an animal, which is of great importance in the lactation period. This trial aimed to evaluate the inclusion of narasin in the diet of lactating ewes on milk yield, composition, dry matter intake (DMI), and plasma metabolites of the ewes and growth rate of lambs. Thirty-two lactating ewes (59.0 ± 2.42 kg) were assigned to a randomized complete block design. The experimental diets contained 500 g/kg of dry matter (DM) of coast cross (Cynodon dactylon (L.) Pers) hay and 500 g/kg DM of concentrate, and the treatments were: N0—no narasin inclusion; N13—inclusion of 13 mg of narasin/kg DM. Once a week, from week 2 to 10 of lactation, ewes were separated from their lambs, injected with oxytocin, and milked mechanically to empty the udder. After 3 h, the milk production was recorded, using the same procedure, and sampled to evaluate the composition. The blood samples were taken weekly, 4 h after feeding. The average daily gain (ADG) and starter DMI of the lambs were evaluated weekly from week 2 to 12 of age. The inclusion of narasin did not affect (P = 0.93) DMI of ewes; however, it increased milk production (P < 0.01) and feed efficiency (P = 0.02; FE). Ewes fed N13 had a greater milk fat (P < 0.01), protein (P < 0.01), lactose (P = 0.04), and total solids production (P < 0.01). Narasin inclusion in ewe’s diet increased plasma glucose concentration (P = 0.05) at weeks 8, 9 and 10; however, there was no effect on plasma urea concentration (P = 0.96). The lambs of N0 ewes had a greater starter DMI (P < 0.01) at weeks 7, 8, 9, and 10; however, the ADG and body weight at weaning and after weaning were similar between treatments (P > 0.05). The results showed that the inclusion of 13 mg of narasin/kg DM improved the milk production and FE of the ewes without altering the composition of the milk. The lower initial consumption of concentrate by N13 lambs before weaning was caused by the higher production of milk. The results obtained in the present study demonstrate the possible productive gain with the inclusion of narasin in diets for lactating ewes.

Investigating various performance traits of Karakul sheep

Karakul sheep in Turkey is an endangered breed according to the total number of ewes. Two herds of Karakul sheep in Tokat Province, reared similar environmental conditions, kept in situ in vivo conservation as a gene resource. This study aimed to determine various performance traits of Karakul sheep reared in breeder conditions as a gene resource. Least squares means for lambing rate (LR), litter size (LS) and lamb production (LP) were found 95.8±0.60%, 1.04±0.01 and 100.0±0.80%, respectively. It was determined that farm and age had significant effect on LR and LP, while farm and year had significant impact on LS. Survival rate in lambs were found 95.2 and 94.1%, respectively on 90th and 180th days. Means of least squares for live weights of lambs at birth and on 90th and 180th days were identified as 3.35±0.02, 21.52±0.27 and 30.34±0.32 kg, respectively. Live weight after shearing and greasy fleece weight values were 40.73±0.12 and 2.04±0.01 kg for females and 62.65±0.53 and 3.48±0.06 kg for males. Lactation milk yield (LMY) was 104.85±3.73 kg in ewes and lactation duration was 159.01±1.70 days. LMY was affected by the lactation number and farm while lactation duration was affected by lactation number. Results revealed that various performance traits of Karakul sheep conserved in breeder conditions were similar to or better than those previously reported for this breed. Also, the breed is similar to medium size native sheep breeds in terms of growth and mature live weight.

Reproductive Performance Following Transcervical Insemination with Frozen Thawed Semen in Ewes Submitted to Surgical Incision of Cervical Folds (SICF): Comparison with Laparoscopic Artificial Insemination.

Simple SummaryThe anatomical barriers of the female reproductive tract and the low quality of the frozen thawed semen of rams are limiting factors in spreading superior genotypes in the ovine species. Artificial insemination (AI) is therefore mostly performed by laparoscopy. The surgical incision of cervical folds (SICF) has been demonstrated to allow transcervical intrauterine semen deposition. Here we present data regarding pregnancy (PR) and lambing (LR) rates obtained by transcervical AI following SICF, compared to those obtained by laparoscopic AI using frozen thawed semen. The results showed that in 89.7% of ewes submitted to SICF intrauterine, the deposition of semen was allowed. Moreover, in both experimental groups, the PR and LR were similar. These observations suggest that SICF could represent a valid preliminary procedure to allow transcervical AI in animals of superior genotypes contributing to genetic improvement.Transcervical artificial insemination (AI) after the surgical incision of cervical folds (SICF) could represent a valid alternative to laparoscopic AI when frozen thawed semen is used. The aim of this experiment was to compare pregnancy (PR) and lambing rates (LR) of ewes submitted either to transcervical AI after SICF or to laparoscopic AI using frozen thawed semen. Pregnant at term ewes (n = 80) were allocated in two experimental groups. After lambing, one group (n = 39) was submitted to SICF. The remaining ewes that were regularly lambed were allocated to the group of laparoscopic AI (n = 40). Six months later, oestrous cycle of both experimental groups was synchronised and all ewes were artificially inseminated with frozen thawed semen. Ewes submitted to SICF underwent transcervical insemination and intrauterine deposition of semen was recorded. The remaining animals were submitted to laparoscopic AI. Pregnancy and LR were recorded. Intrauterine deposition of semen was possible in 89.7% pf ewes submitted to SICF. This group showed similar PR and LR compared to the laparoscopic group (respectively: PR, 71.8% vs. 70% and LR, 64.1% vs. 65%; p > 0.05). Transcervical AI after SICF may represent a valid alternative to laparoscopy in AI protocols requiring the use of frozen thawed semen.

PSXII-1 Effects of early weaning on feed intake, growth performance, and diarrhea rate of Hu lambs

Abstract The objective of this study was to evaluate the effects of early weaning on growth performance, feed intake and diarrhea rate of Hu lambs, and establish the experimental model of early weaning stress in lambs. A total of 60 neonatal male Hu lambs were randomly allotted into 10 pens and 6 lambs in each pen with their ewes. Five pens of lambs were weaned at 21days of age as early weaning group (EW group), and the other 5 pens of lambs were remained with their ewes as control group (CON group). Body weight (BW) were recorded at birth (d0) and at d7, 14, 21, 22, 24, 26, 28, 35,42 and 49 after birth. Solid feed intake of lambs in each pen was recorded and diarrhea incidence was also monitored on daily basis. Data was analyzed using the MIXED model of SAS, and statistical significance was determined at P &amp;lt; 0.05. There was no difference in BW at birth and d21 between the two groups of lambs (P &amp;gt; 0.05). However, BW and average daily gain (ADG) of the lambs in EW group were significantly lower than those in CON group (P &amp;lt; 0.01) since weaning. Solid feed intake of the lambs in EW group were obviously higher than that in CON group (P &amp;lt; 0.01). In addition, the diarrhea rate was significantly higher than that in CON group from d21 to d35 (P &amp;lt; 0.01). The results indicated that lambs weaned at d21 showed strong stress response by significantly decreasing in BW and ADG, and had more feed intake but higher diarrhea rate. Future study is warranted to determine the changes in gut microbiota and barrier function to assess the mechanism of early weaning on health status and growth performance of lambs, and to investigate nutritional intervention methods to alleviate weaning stress.

PSX-35 The relationship between the survival rate of lambs and the amount of cubs in the litter

Abstract Safety and polycarpous in sheep farming is one of the most important factors determining the economic efficiency of the industry. The increase in the number of lambs in the litter is accompanied by undesirable phenomena, such as weight loss and linear measurements of the fetus and, as a result, this affects their survival. The aim of the research was to study the relationship of the polycarpous of sheep with the safety of lambs. A litter of Romanov breed sheep (n = 28) and their hybrids with argali (n = 57) was studied. For statistical data analysis used SPSS V.15.0. To determine the relationship between the number of lambs in the litter and their safety, contingency tables and the chi-squared test were used. Ewes were inseminated during the breeding season (October – November). The 210 lambs were obtained from 85 ewes. The safety of lambs up to 4 months of age averaged 63%. However, this figure, depending on the number of lambs in the litter, was significantly different. The safety of the lambs from ewes that have been the only ones was 100% before the retention, where there were twins - the safety was 85%. More than 48% of lambs from litter with three cubs were perished in the first months of life. Up to 4 months of age in a litter of 5 lambs survived 33% of those born (n = 5). The numbers of cubs in the litter were affected to the safety of the lambs, which can be argued from the obtained results. This is also evidenced by the obtained difference between the expected and actual mortality rates in litters and the significant chi-squared value. The study was supported by the RSF within Project no.18-16-00079.

Identification of novel genes associated with litter size of indigenous sheep population in Xinjiang, China using specific-locus amplified fragment sequencing technology.

BackgroundThere are abundant sheep breed resources in the Xinjiang region of China attributing to its diverse ecological system, which include several high-litter size sheep populations. Previous studies have confirmed that the major high prolificacy gene cannot be used to detect high litter size. Our research team found a resource group in Pishan County, southern Xinjiang. It showed high fertility with an average litter size of two to four in one birth, excellent breast development, and a high survival rate of lambs. In the present study, we used this resource as an ideal sample for studying the genetic mechanisms of high prolificacy in sheep.MethodsIndigenous sheep populations from Xinjiang, with different litter sizes, were selected for the research, and specific-locus amplified fragment sequencing (SLAF-seq) technology was used to comprehensively screen single nucleotide polymorphisms (SNPs) from the whole genome that may cause differences in litter size. Novel genes associated with litter size of sheep were detected using genome-wide association studies (GWAS), providing new clues revealing the regulation mechanism of sheep fecundity. Candidate genes related to ovulation and litter size were selected for verification using Kompetitive Allele Specific polymerase chain reaction (KASP) cluster analysis.ResultsWe identified 685,300 SNPs using the SLAF-seq technique for subsequent genome-wide analysis. Subsequently, 155 SNPs were detected at the genome-wide level. Fourteen genes related to sheep reproduction were notated: COIL, SLK, FSHR, Plxna3, Ddx24, CXCL12, Pla2g7, ATP5F1A, KERA, GUCY1A1, LOC101107541, LOC101107119, LOC101107809, and BRAF. Based on literature reports, 30 loci of seven genes and candidate genes (CXCL12, FSHR, SLK, GUCY1A1, COIL, LOC101107541, and LOC101107119) related to ovulation and litter size were selected for verification using KASP cluster analysis. Among them, nine loci of three genes were successfully genotyped. Three loci of FSHR (GenBank ID: 443299, g. 75320741G>A site), GUCY1A1 (GenBank ID: 101110000, g. 43266624C>T site), and COIL (GenBank ID: 101123134, g. 7321466C>G site) were found to be significantly or extremely significantly associated with litter size. These three loci are expected to be used as molecular markers to determine differences in litter size in sheep.

Effect of the Booroola fecundity (FecB) gene on the reproductive performance of ewes under assisted reproduction

Reproductive traits are important factors in sheep production. The Booroola fecundity (FecB) gene—the first major gene for prolificacy identified in sheep—has a positive effect on ovulation rates and litter size under natural reproductive conditions. However, the effect of the FecB gene on reproductive performance under assisted reproduction, which uses many artificial hormones, remains unclear. In the present study, we evaluated the effect of FecB (BMPR-1B mutation) on reproductive performance under assisted reproduction, and examined offspring body weight at birth and weaning and survival rate at weaning. There were no differences among three genotype groups (homozygous carrier, BB; heterozygous carrier, B+; non-carrier, ++) in terms of estrus detection rate, time to estrus onset, or estrus duration following estrus synchronization (P > 0.05). The pregnancy rates at 60 d were similar among three genotype groups after artificial insemination (P > 0.05). However, the B allele had an additive effect on litter size (one copy resulted in an increase of 0.88 lambs and two copies produced an additional 0.41 lambs; P < 0.01), and increased lambing and fecundity rates (P < 0.01). After multiple ovulation, the average numbers of recovered embryos per ewe were 9.16 ± 0.79, 8.20 ± 0.77, and 8.44 ± 0.61 in the BB, B+, and ++ ewes, respectively (P > 0.05). There were no differences in the fertilization rate or numbers of grade 1–2 embryos among different groups (P > 0.05). The birth and weaning weights of lambs from BB and B+ ewes were lower than those of lambs born from ++ ewes (P < 0.01) owing to the high fecundity. The survival rate of lambs at weaning did not differ among groups (P > 0.05). Our results indicated that the presence of the B allele had an additive effect on litter size after artificial insemination, but it did not influence the parameters of estrus synchronization and multiple ovulation. Furthermore, the higher prolificacy in ewes carrying the B allele was associated with a reduction in offspring body weight at birth and weaning.

Effect of Age and Weaning on Growth Performance, Rumen Fermentation, and Serum Parameters in Lambs Fed Starter with Limited Ewe-Lamb Interaction.

Simple SummaryEarly weaning is a common practice in the modern lamb industry, which shortens the breeding cycle of ewes and improves the flock productivity by increasing the frequency of lambing. Recently, it was suggested that weaning age (21 or 35 days of age) and milk replacer feeding level had limited effect on apparent digestibility of nutrients in lambs. However, artificial rearing may increase the cost due to the use of milk replacer, labor, and feeding facilities. In this study, we compared the difference in growth performance of lambs weaned at 21 days (early weaning) and 49 days (conventional weaning) of age. All lambs were initially reared with ewes and supplemented with starter at 7 days of age. The results showed that diarrhea rate was increased when lambs were weaned at 21 days of age while average daily gain was decreased. Early weaning reduced average daily gain without compromising lambs’ overall immunity. In conclusion, early weaning (21 days of age) may have a negative impact on lambs’ performance based on a short-term study.Sixty neonatal Hu lambs were weaned at either 21 (n = 30) (early weaning, EW) or 49 days (n = 30) of age (control, CON). The starter intake and body weight (BW) of lambs was recorded weekly from birth to 63 days of age. Diarrhea rate of lambs was measured from birth to 35 days. Six randomly selected lambs from each treatment were slaughtered at 26, 35, and 63 days of age, respectively. Ruminal pH, NH3-N, and volatile fatty acid (VFA) concentration, as well as serum parameters including immunity, antioxidant status, and inflammatory parameters from randomly selected lambs from each treatment were measured. There was no difference in BW at birth and day 21 between the two groups of lambs (p > 0.05). However, BW of the lambs in the EW group was significantly lower than those in the CON group (p < 0.01) from 28 to 49 days of age. Average daily gain (ADG) of the lambs in the EW group was significantly lower than those in the CON group (p < 0.01) at three weeks after early weaning. Starter intake of the lambs in the EW group was obviously higher than that in the CON group (p < 0.01) from day 28 to 49. In addition, the diarrhea rate was significantly higher than that in the CON group from day 5 to 14 after weaning (p < 0.01). The EW group had heavier carcasses (p < 0.01) and rumen relative to whole stomach weights (p < 0.01). Rumen pH was increased by age (p < 0.01) and was not affected by early weaning (p > 0.05). Early weaning decreased abomasum relative to whole stomach weight (p < 0.01) and increased total VFA concentrations (p < 0.01) at day 26. There was no difference in lambs’ immunity and stress indicators (p > 0.05). The results indicated that lambs weaned at 21 days of age had decreased ADG and higher diarrhea rate, although the overall immunity was not compromised. Long-term study is needed to further validate the feasibility of early weaning strategy in lambs.