Survival Rate Of Lambs Research Articles

Impact of change in body condition score in mid-late pregnancy in ewes fed a mixed diet on lamb survival and performance

The objective of this study was to evaluate the effect that body condition score of pregnant ewes fed on turnip and swede crops during mid-late gestation had on offspring survival and performance. Data were collected from 755 multiparous mixed-age ewes carrying 1–4 fetuses. Ewes grazed a turnip crop for 1 month prior to pregnancy scanning with supplementary ryegrass/clover baleage (~75 days gestation) followed by a swede crop with supplementary Lucerne baleage for 1 month following pregnancy scanning (to ~120 days gestation). Ewe body condition score (BCS) at mating, pregnancy scanning and pre-lambing, along with lamb survival and growth rates to weaning were recorded. Lamb survival from pregnancy scanning to tailing differed by litter size (P<0.001) with lower survival in litters with 3 or more lambs compared to singles and twins which did not differ. Improving BCS from pregnancy scanning to 120 days gestation had a positive effect on lamb survival irrespective of litter size and ewe age (P<0.001). Lamb survival in ewes ≥5 years of age, irrespective of litter size, was lower (P<0.001) compared to 2 or 3–4-year-old ewes, which in turn did not differ from each other. The key finding of the study was that loss in BCS from pregnancy scanning to 120 days gestation, negatively impacted on lamb survival, especially in ewes carrying 3 or more fetuses and in ewes >5 years of age irrespective of the number of fetuses carried. Furthermore, there was high variation in BCS change observed in both early and mid-pregnancy.

Maternal Supplementation with Dietary Betaine during Gestation to Improve Twin Lamb Survival.

Simple SummaryHigh incidences of twin lamb mortality constrain the reproductive efficiency and productivity of Merino sheep flocks. This study determined whether supplementing the diets of pregnant, twin-bearing ewes with 2 or 4 g/day of betaine would improve lamb viability and survival to weaning. Feeding ewes 2 g/day of betaine for the duration of pregnancy decreased lamb survival but increased lamb body weight at weaning. Whereas, lamb vigour and early post-natal survival were improved following ewe supplementation with 4 g/day of betaine during the second half of pregnancy. Maternal supplementation with 4 g/day of betaine during the second half of pregnancy may, therefore, be a useful strategy to improve twin lamb survival.Betaine increases the synthesis of creatine, an energy-rich amino acid that increases adenosine triphosphate (ATP) and has neuroprotective properties which may improve post-natal lamb survival. This study determined whether maternal betaine supplementation during gestation would improve body weight, thermoregulation, time to stand and suck, colostrum intake and survival to weaning of twin lambs. Twin-bearing Merino ewes received dietary betaine at either 0 g/day (Control, CTL), 2 g/day from ram introduction to parturition (Early betaine, EB) or 4 g/day from Day 80 of gestation to parturition (Late betaine, LB). Ewes were housed individually during parturition and measures were collected at 4, 24 and 72 h and Day 7 post-partum, and at marking (53.2 ± 0.2 days of age) and weaning (99.3 ± 0.2 days of age). The EB treatment resulted in heavier lambs at weaning compared with CTL and LB lambs (p < 0.05). Time to stand and suck from birth was longer in EB lambs (p < 0.05), whereas, the interval from birth to first suck was shorter for LB lambs (p < 0.05). Lamb survival rate was the highest for LB lambs at 72 h and Day 7 (p < 0.05), and lowest for EB lambs on Day 7 (p < 0.05). These data indicated that betaine supplementation at 4 g/day during the second half of pregnancy improved twin lamb survival to Day 7 and shortened the interval from birth to first suck; whereas feeding ewes 2 g/day of betaine for the duration of pregnancy increased twin lamb body weight at weaning, but increased both the time to attain behavioural milestones and mortalities before Day 7.

Effect of supplementation of unprotected or protected arginine to prolific ewes on maternal amino acids profile, lamb survival at birth, and pre- and post-weaning lamb growth

This research determined the effects of dietary supplementation with rumen-protected arginine (Pro-Arg) on metabolites and amino acids in maternal plasma and lamb survival rate at birth (LSRAB) in prolific Afec-Assaf ewes. The hypothesis was that Pro-Arg, the precursor for nitric oxide and polyamines, would increase placental development and vascularity, uteroplacental blood flow, and nutrient transport and reduce oxidative stress to increase LSRAB. Ewes were fed either their basal diet, basal diet with Pro-Arg, or basal diet with unprotected arginine (Unp-Arg; 18 g/head/d). The supplemental arginine was about 1% of the dry matter intake from day 40 or 60 of gestation until parturition. Ninety-two of 98 ewes produced live lambs. Ewes fed Pro-Arg had greater (P = 0.002) concentrations of arginine and other amino acids in plasma, whereas Unp-Arg did not affect concentrations of arginine, but decreased (P < 0.05) concentrations of some amino acids. There was no effect of treatments on gestation length (144 ± 2 d), prolificacy (2.65 lambs born per ewe), LSRAB (0.80), body weight (88.8 ± 10.8 kg), and body condition score (2.8 ± 0.6) of ewes, or birth weight and crown-rump length of lambs. The GI (BW/CRL1.5) was affected by sex of lamb (P = 0.008), parity of ewe (P = 0.002), litter size (P = 0.0001), and lamb status (P = 0.003). Of 229 lambs born, 32 were dead and 16 died before 5 mo of age, leaving 181 lambs with records on weights at birth and 5 mo of age. Interestingly, lambs born to ewes fed the Unp-Arg and Pro-Arg weighed 3.6 kg less at postnatal day 150 than lambs from control ewes.

Reproductive and productive characteristics of hair sheep raised in the tropical region grassland of Brazil

We aimed to characterize the energetic profile of hair sheep (Ovis aries) raised on pasture in a tropical climate country and verify it is influence on productive and reproductive parameters. A total of 68 non-pregnant adult ewes were randomly distributed into four genetic groups (GGs) according to coat color (Red-coated Santa Inês GG – 17, Black-coated Santa Inês GG – 13, White-coated Morada Nova GG – 28 and Red-coated Morada Nova GG – 10). We collected blood samples at the beginning and at the end of the breeding season. The reproductive efficiency of the ewes was evaluated by fertility, prolificacy, lamb survival rate, and lamb body weight at birth and weaning. We performed statistical analyses using the package PROC GLM and the chi-square (χ2) test from SAS software. The genetic group influenced serum glucose and β-hydroxybutyrate concentrations, prolificacy, and lamb body weight. Male lambs were heavier than female lambs at birth and weaning. Twin lambs were lighter at birth and at weaning than were single lambs. The genetic group, lamb birth rank, and sex influenced the lamb body weight at birth and weaning. This study presents important information on the reproductive efficiency of these hair sheep that are relevant to tropical climate countries. The blood parameters found in this research show that there are important metabolic differences between hair sheep in the semi-arid region of Northeast Brazil. Morada Nova sheep with independent white coat color, higher reproductive performance in tropical conditions.

Environmental Influences on Dall's Sheep Survival

ABSTRACTUnderstanding how species respond to environmental conditions can assist with conservation strategies and harvest management, especially in arctic and boreal regions that are experiencing rapid climate change. Although climatic influences on species distributions have been studied, broad‐scale effects of climate on survival are less well known. We examined the interactive effects of meteorological and remotely sensed environmental variables on survival of Dall's sheep (Ovis dalli dalli) lambs and adults by synthesizing radio‐telemetry data across their range. We used data from 9 studies of adult sheep and 2 studies of lambs that were conducted between 1997 and 2012 at sites spanning the species' range in Alaska, USA, and northwestern Canada. We obtained environmental variables throughout the range of Dall's sheep, including the normalized difference vegetation index (NDVI) from optical remote sensing, freeze‐thaw frequency (FTF) from passive microwave remote sensing, and gridded climate variables such as snow water equivalent, temperature, and precipitation. We used Cox proportional hazard regression to investigate the effects of environmental variables recorded during summer, winter, and the previous winter on annual survival rates of Dall's sheep lambs and adults. Summer NDVI was the most influential environmental factor affecting lamb survival, with improved lamb survival occurring in years with a high maximum NDVI. Also, lamb predation by coyotes (Canis latrans) and golden eagles (Aquila chrysaetos) decreased substantially with increasing NDVI. The previous winter FTF had the strongest effect on adult survival, with decreased survival occurring after winters with high FTF. In addition, these remotely sensed environmental factors interacted with meteorological factors to affect survival, such that effects of winter temperature depended on summer NDVI and winter FTF. Warm winters increased lamb survival only when preceded by summers with high NDVI, and warm winters increased adult survival only when winter FTF was low. Thus, potential benefits of climate warming may be counteracted if wintertime freeze‐thaw events markedly increase. Correlations among environmental variables across sites were low, and regional climate cycles such as the Pacific Decadal Oscillation (PDO) had weak effects, indicating substantial local variability in climatic conditions experienced by Dall's sheep across their range. These findings can help managers anticipate how Dall's sheep populations will respond to changes in local environmental conditions. Our results also highlight the utility of multiple remotely sensed environmental conditions for ungulate management, especially passive microwave products that provide valuable information on winter icing events. © 2020 The Wildlife Society.

Supplementation of Underfed Twin-Bearing Ewes with Herbal Vitamins C and E: Impacts on Birth Weight, Postnatal Growth, and Pre-Weaning Survival of the Lambs.

Simple SummaryIn twin-bearing ewes, undernourishment during pregnancy lowers the birth weight and increases morbidity and mortality of lambs. One of the causes is oxidative stress, which can be prevented by supplementing antioxidant vitamins. In the present study we tested the effect of supplementation with herbal vitamins C and E alone or in combination with concentrate on pregnancy outcomes and growth and survival of lambs during early postnatal stages (lactation). The results showed that vitamin supplementation increased offspring birth weight and antioxidant capacity, with a trend towards higher body weight (BW) at weaning. Nutritional supplementation only had a positive effect on birth weight, meanwhile combined supplementation of vitamins and concentrate improves the lamb response. Lambs’ survival was not affected by the treatment, although absolute values of survival were higher in vitamin-treated groups. It is concluded that supplementation with herbal vitamins C and E alone or in combination with concentrate during pregnancy may constitute a good nutritional strategy to improve productivity in sheep herds reared in harsh environmental conditions.Twin-bearing pregnancies of sheep reared in harsh environmental conditions result in maternal undernutrition and feto-maternal oxidative stress, leading to intrauterine growth restriction (IUGR). We assessed the efficiency of supplementation with antioxidant herbal vitamins C and E alone or in combination with concentrate throughout gestation on pregnancy outcomes, pre-weaning growth, and survival of twin lambs from grazing ewes at the Magellan Steppe. Four groups (n = 30 each) of twin-bearing ewes received a base natural prairie (P) diet, supplemented with either herbal vitamins C 500 mg and E 350 IU per day (V) or concentrated food (S); groups were: P, P + V, P + S, and P + VS. Vitamins and concentrate were supplemented until parturition. At birth, lambs were weighed, and blood was drawn for total antioxidant capacity (TAC) evaluation. Lamb body weight (BW) and survival rate were evaluated at mid-lactation (60 days) and at weaning (120 days). Vitamin supplementation resulted in increased lamb birth weight and TAC, with a trend towards higher BW at weaning, while nutritional supplementation only had a positive effect on birth weight. Lamb survival was higher in both vitamin supplemented groups. In conclusion, supplementation with herbal vitamins C and E alone or in combination with concentrate food during pregnancy may constitute a good nutritional strategy for sheep reared in harsh environmental conditions.

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.

Genetic parameter estimates for reproductive traits in Chokla ewes of India.

Early selection of ewes for better reproductive performance may reduce generation interval and increase genetic gains. Considering this, the present study aimed to derive the genetic parameter estimates of ten reproductive traits in 1172 maiden Chokla ewes over a period of 22years. Initially, the traits, namely age at first service (AFS), weight at first service (WFS), age at first successful service (ASS), weight at first successful service (WSS), age at first lambing (AFL), ewe's weight at first lambing (WFL), first lambing interval (LI1), first service period (SP1), first parity lamb survival (SUR1) and first service fertility rate (FER1) were analysed for the effects of genetic and non-genetic factors. The significant effects were fitted into six animal models to estimate the genetic parameters. The heritability estimates were low for the age traits and FER1 (0.06-0.09) but moderate for the rest of the traits (0.16-0.23), indicating the suitability of these traits for improvement through direct selection. The maternal direct and permanent effects were meagre for all the traits. The ewe weights had strongly negative correlations with the age of sexual maturity and positive correlations with lamb survival. The results emphasise the need to optimize the weights of maiden ewes to improve reproductive performance.

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.

Survival and cause‐specific mortality of desert bighorn sheep lambs

ABSTRACTJuvenile recruitment in desert bighorn sheep (Ovis canadensis mexicana) is highly variable, yet the mechanisms influencing neonate survival are not well understood. Because few studies have equipped desert bighorn sheep lambs with telemetry collars, definitive data on cause‐specific mortality, and lamb survival estimates are lacking. Our objectives were to estimate lamb survival rates and determine cause‐specific mortality for desert bighorn sheep lambs during a period of mountain lion (Puma concolor) and coyote (Canis latrans) removal in southwestern New Mexico, USA. We captured pregnant adult females each fall and fitted them with a telemetry collar and a vaginal implant transmitter to aid with neonate captures. We captured and radio‐collared 12 desert bighorn sheep lambs in 2012 and 14 in 2013 within 48 hours of parturition in the Peloncillo Mountains, New Mexico. We estimated lamb survival to 6 months of age. Across both years there were 14 mortalities, 12 of which were due to predation. Mountain lions killed 5 lambs (2 in 2012 and 3 in 2013), coyotes killed 4 lambs (all in 2013), a gray fox (Urocyon cinereoargenteus) killed 1 lamb in 2012, and 2 lambs were killed by unknown predators in 2013. Staged‐based survival estimates indicated the highest mortality rates occurred in the first week post birth; 5 of 14 lamb mortalities occurred before 7 days of age. Lamb survival to 6 months was substantially lower in 2013 (0.20 ± 0.11 [SE]) than in 2012 (0.71 ± 0.14) with the differences in survival attributed to increased coyote predation in 2013. We did not detect differences in body mass at birth between years or differences in body mass, chest girth, or neck circumference at birth between lambs that were killed by predators and those that survived. Coyotes, mountain lions, and the gray fox killed lambs &lt;8 weeks of age, but only mountain lions killed lambs &gt;8 weeks old. Predator removals focused around the parturition period of desert bighorn sheep may be more likely to influence lamb survival rates than removals outside of the lambing season. © 2018 The Wildlife Society.

Comparison of Mutton Charollais Lambs and Their Cross Lambs Born from Indigenous Fat Tailed and F1 Prolific Breed Ewes

The objective of this study was to evaluate the effects of dam breed on lambs sired by Charollais rams and purebred Charollais lambs obtained via embryo transfer. Frozen Charollais semen and embryos, used to obtain crossbreed and purebred Charollais lambs, were imported from elite flock with pedigrees and progeny test in Canada.The study was conducted on the crossbred Charollais lambs born from Tushin, and Romanov F1 ewes (Romanov × Morkaraman), and Charollais lambs born from Awassi, Morkaraman and Tushin surrogate ewes. The data was collected on 61 lambs (23 Charollais: CH, 20 Tushin × Charollais: F1 CH and 18 Charollais × Romanov F1:COR) from birth to weaning. Average weights at birth for CH, F1 CH and COR lambs were 4.32 ± 0.18 kg, 4.17 ± 0.18 kg, 3.18 ± 0.19 kg and at the age of 60 days were 21.20 ± 1.07 kg, 20.94 ± 0.84 kg, 18.13 ± 0.91 kg, respectively. The genotype of dams significantly affected birth and weaning weights of crossbred lambs, but not average daily live weight gain (ADG). Litter size had constant significant effect on the traits evaluated. Survival rates of crossbred lambs from birth to weaning were affected by the dam genotype. Birth weights and survival rates of CH lambs born from embryo transfer were affected by recipient genotypes and Awassi ewes were found to be the best surrogate mothers.

AANAT transgenic sheep generated via OPS vitrified-microinjected pronuclear embryos and reproduction efficiency of the transgenic offspring.

BackgroundThe open pulled straw (OPS) vitrification method has been successfully applied in mouse, pig, and goat embryos as well as in buffalo oocytes, but it has not yet been applied to the microinjected embryos. This study examined the effects of OPS vitrification on embryo development and the reproductive capacity of the transgenic offspring in order to establish a method for preservation of microinjected embryos.MethodsOvine pronuclear embryos were microinjected with the exogenous aralkylamine N-acetyltransferase gene (AANAT), frozen by the OPS method, and subsequently thawed for embryo transplantation. Pregnancy rate, lambing rate, survival rate, average birth weight and transgenic positive rate as well as reproduction efficiency and hormone level of the transgenic offspring were investigated to analyze the effect of OPS vitrification on microinjectd pronuclear embryos.ResultsNo significant differences were observed in the birth rate, lamb survival rate and transgenic positive rate between the frozen and non-frozen AANAT-microinjected pronuclear embryos. The average birth weight of the frozen embryos offspring was greater than that of the non-frozen embryos. Importantly, the transgenic offspring that overexpressed the AANAT gene showed improved ovulation efficiency and lambing rate by regulating their hormone levels.ConclusionsThe OPS vitrification approach may be a valuable method in microinjected- embryo transfer technology, which could reserve embryos and result in fewer unnecessary animal sacrifices. In addition, the AANAT+ transgenic offspring exhibited improved reproductive capacity on account of regulation effect of melatonin on reproductive hormone. These data may provide available references for human-assisted reproduction.

Some Growth, Reproduction and Lactation Characteristics of Hamdani Sheep

This research was conducted to determine some growth reproduction and lactation characteristics of fat tailed Hamdani sheep in extensive farm conditions in the Çığlı village of Çukurca district of Hakkari Province in Turkey. It was found out that average of birth weight, weaning weight and 6th month live weight were 4.13, 21.78 and 35.09 kg respectively. The average daily gains from birth to weaning and from birth to the 6th month were 171.98 and 196.30 g respectively. Hamdani, sheep giving birth between December to February, it’s reproduction characteristics such as lambing rate, infertility rate, fecundity, twinning rate and litter size were found to be 92%, 8%, 1.04, 13.05% and 1.13 respectively. The survival rates of lambs until the 7th and 90th (until weaning) days were 98.5% and 94.6% respectively. The means of lactation milk yield and lactation length for ewes were 83.96 L and 170.98 days respectively. Consequently, it was concluded that Hamdani sheep had a better performance over performance for traits in question compared to Turkish native sheep breeds and some certain cross breeds developed and recently known in Turkey.

Growth of lambs receiving a supplementary milk replacer or reared traditionally in a flock of Polish Heath sheep

The aim of the study was to compare the body weight gain and survival rate of lambs receiving a milk replacer as supplementary feed with lambs reared traditionally. The research was conducted in a flock of Polish Heath sheep. Of 244 lambs born, 42 lambs from multiple births were given supplementary feed. The lambs received the milk replacer until the 35th day of rearing. Body weight was monitored at birth and on days 28, 56 and 100 of life. Reproductive parameters and survival rate of lambs were derived from breeding documentation. There were no significant differences in the survival rate of lambs in the two groups, which was above 80%. The average birth weight of lambs reared traditionally and of those receiving the milk replacer was similar. During the entire rearing period, the lambs that required supplementary feeding grew more slowly. Twin lambs receiving the supplement and twin lambs reared traditionally had similar body weight and daily gains up to the 56th day of life, but the twin lambs receiving supplementary feed had a significantly lower body weight at day 100 and growth rate during the entire rearing period. The growth rate of triplets fed supplementary milk replacer was not significantly different from that of triplets reared traditionally in any period of the study.

Husbandry procedures at the point of lambing with reference to perinatal lamb mortality

Perinatal mortality reduces the number of lambs sold per ewe and consequently impacts negatively on the economic sustainability of sheep farming. Figures quoted for the incidence of perinatal lamb mortality...

Weaner survival is heritable in Australian Merinos and current breeding objectives are potentially leading to a decline in survival

There is little evidence to show that mortality rates during the period after weaning are improving over time in Australian sheep. The average mortality rate of Merino lambs during the post-weaning period has been estimated to be 5.2%. The present study explored the potential for producers to breed for improved survival rates during the post-weaning period and the potential impact this would have on key production traits. A total of 122526 weaner survival (mortality) records were obtained from 18 Merino flocks, between 1989 and 2014, encompassing a wide variety of Australian Merino sheep types and production systems. The heritability of weaner survival from a sire model was estimated to be 0.07 ± 0.01 and was significantly greater than zero. The survival of lambs post-weaning was significantly influenced by weaning weight, with higher survival rates observed in the heavier lambs. The phenotypic relationship with weight indicates that selection for heavier weaning and post-weaning weights, and in turn larger growth rates, will improve survival rates. There is genetic variation in weaner survival not explained by the relationship with weaning weight. Weight-corrected weaner survival was antagonistically genetically correlated with fleece weight. Due to these antagonistic genetic relationships selection based on popular MERINOSELECT indexes is leading to a very small reduction in the survival rate of lambs after weaning through to the post-weaning stage. To prevent a decline in weaner survival, producers are advised to record weaner survival and include it in their breeding objective.

Akkaraman Koyunlarında Gebeliği Son Döneminde Yapılan Ek Yemlemenin Kuzularda Doğum ve Çeşitli Dönemlerdeki Canlı Ağırlıklar Üzerine Etkisi

Bu çalışma, Kırşehir İlinde yetiştirilen Akkaraman ırkı koyunlarda gebeliğin son döneminde yapılan ek yemlemenin kuzularda doğum ve çeşitli dönemlerdeki ağırlıklar üzerine etkisinin belirlenmesi amacı ile yapılmıştır. Araştırma materyalini, 580 baş Akkaraman koyunu ve bunların 2015 doğum sezonunda doğurmuş oldukları 554 baş Akkaraman kuzusu oluşturmuştur. Akkaraman koyunları iki gruba ayrılmıştır. Her iki gruba da buğday samanı gebelik süresince verilmiştir. Ek yemleme grubuna (EYG), gebeliğin son döneminde buğday samanına ek kesif yem (400 gr/hayvan) verilmiştir. Kontrol grubuna (KG) ise gebelik süresince sadece buğday samanı verilmiştir. Araştırmada kuzuların çeşitli dönem canlı ağırlıkları, yaşama güçleri ve Akkaraman koyunlarının bazı döl verim özellikleri incelenmiştir. Akkaraman koyunlarında döl verim özelliklerinden kısırlık oranı, doğum oranı, ikizlik oranı, yavru atma oranı, koç altı koyun başına kuzu sayısı ve doğuran koyun başına kuzu sayısı değerleri EYG ve KG gruplarında sırasıyla %12 ve %9, %86 ve %91, %13 ve %5, %2 ve %0, 0,96 ve 0,95, 1,12 ve 1,04 olarak bulunmuştur. Kuzularda yaşama gücü 90. gün ve 120. günde EYG ve KG gruplarında sırasıyla %84, %80 ve %91, %91 olarak tespit edilmiştir. Akkaraman kuzularının doğum, 90. ve 120. günlük yaştaki canlı ağırlık ortalamaları EYG ve KG gruplarında sırasıyla 5,82±0,06 kg, 30,94±0,44 kg, 35,91±0,09 kg ve 3,43±0,05 kg, 30,17±0,39 kg, 30,84±0,39 kg olarak tespit edilmiştir. Ek yemlemenin, cinsiyet ve doğum tipine göre, doğum ağırlığı ve 120. gün yaş ağırlığı üzerine etkisi önemli bulunmuştur. 90. gün ağırlığı bakımından ise sadece doğum tipinin etkisi çok önemli bulunmuştur. Sonuç olarak, gebeliğin son döneminde yapılan ek yemlemenin kuzuların doğum ve 120. gün ağırlıklarını artırdığı tespit edilmiştir.

Embryo survival and birth rate after minimum volume vitrification or slow freezing of in vivo and in vitro produced ovine embryos

The objective was to evaluate pregnancy outcomes and birth rate of in vivo derived vs. in vitro produced ovine embryos submitted to different cryopreservation methods. A total of 197 in vivo and 240 in vitro produced embryos were cryopreserved either by conventional freezing, or by vitrification with Cryotop or Spatula MVD methods on Day 6 after insemination/fertilization. After thawing/warming and transfer, embryo survival rate on Day 30 of gestation was affected by the source of the embryos (in vivo 53.3%, in vitro 20.8%; P < 0.05) and by the method of cryopreservation (conventional freezing 26.5%, Cryotop 52.0%, Spatula MVD 22.2%; P < 0.05). For in vivo derived embryos, survival rate after embryo transfer was 45.6% for conventional freezing, 67.1% for Cryotop, and 40.4% for Spatula MVD. For in vitro produced embryos, survival rate was 7.3% for conventional freezing, 38.7% for Cryotop, and 11.4% for Spatula MVD. Fetal loss from Day 30 to birth showed a tendency to be greater for in vitro (15.0%) rather than for in vivo produced embryos (5.7%), and was not affected by the cryopreservation method. Gestation length, weight at birth and lamb survival rate after birth were not affected by the source of the embryo, the cryopreservation method or stage of development (average: 150.5 ± 1.8 days; 4232.8 ± 102.8 g; 85.4%; respectively). This study demonstrates that embryo survival and birth rate of both in vivo and in vitro produced ovine embryos are improved by vitrification with the minimum volume Cryotop method.