Lamb Birth Weight Research Articles

Mortality pattern of Deccani lambs in organized farm condition

The higher mortality was recorded in the early age (0–3 months) and mortality decreased with the advanced of age. According to birth weight of lambs, the highest mortality rate was found in 3.5 kg birth weight groups. In Deccani lambs the highest mortality was recorded in summer season, followed by rainy season and lowest in winter season. Respiratory (31.01%) and alimentary disorders (15.98%) were the dominant causes of mortality in lambs.

Osteoarthritis of the temporo-mandibular joint in free-living Soay sheep on St Kilda

Osteoarthritis (OA) is a common degenerative disease of synovial joints with the potential to cause pathology and welfare issues in both domestic and wild ruminants. Previous work has identified OA of the elbow joint in domestic sheep, but the prevalence of OA of the jaw and in particular the temporomandibular joint (TMJ) has not been previously reported. Following up a previous report of a single case of TMJ OA in a free-living population of Soay sheep on St Kilda in the Outer Hebrides, an archive of 2736 jaw bones collected from this population between 1985 and 2010 was surveyed.Evidence of TMJ OA was found in 35 sheep. Of these, 15 cases were unilateral (11 right side, 4 left side) and the remaining 20 were bilateral. TMJ pathology was much more common in females than males: only 3/35 cases were in males, with overall prevalence at 2.3% for females and 0.2% in males. Radiographic examination of TMJ with OA revealed extensive bone re-modelling with osteophytosis, particularly of the condyle of the mandible. There was a highly significant age-dependence in TMJ OA incidence among age classes: 30/35 cases occurred in geriatric sheep (aged 7 years or more; 11.1% prevalence within this age class), four in adults (2–6 years old; 0.9% prevalence), one in yearlings (0.3% prevalence) and none in lambs. The low incidence in males was confounded by sex differences in longevity: while 18% of females sampled died in the geriatric age class, only 2% of males did so.Although the low prevalence of the pathology limited the ability to test its association with other traits, it was possible to examine relationships with reproductive performance measures amongst geriatric females with and without TMJ OA. Although there were trends towards lower fecundity and lower lamb birth weight in the breeding season prior to death, these were not statistically significant.

Exposure to ergot alkaloids during gestation reduces fetal growth in sheep.

Tall fescue [Lolium arundinaceum (Schreb.) Darbysh; Schedonorus phoenix (Scop.) Holub] is the primary cool season perennial grass in the eastern U.S. Most tall fescue contains an endophyte (Neotyphodium coenophialum), which produces ergot alkaloids that cause vasoconstriction and could restrict blood flow to the fetus in pregnant animals. The objective of this study was to examine fetal growth during maternal exposure to ergot alkaloids during gestation. Pregnant ewes (n = 16) were randomly assigned to one of two dietary treatments: (1) endophyte-infected (N. coenophialum) tall fescue seed (E+; 0.8 ug of ergovaline /g diet DM) and (2) endophyte-free tall fescue seed (E−; 0.0 ug of ergovaline/g diet DM). Birth weight of lambs was reduced by 37% for E+ compared to E−. Organ and muscle weights were also lighter for E+ than E−. Exposure to ergot alkaloids in utero reduces fetal growth and muscle development.

Effects of maternal undernutrition during late gestation and/or lactation on colostrum synthesis and immunological parameters in the offspring.

The emerging immune system is vulnerable to insult not only during fetal life, but also through colostrum transfer of maternal factors with immunomodulatory functions. The aim of the present study was to examine the effects of maternal undernutrition during late gestation and/or lactation on colostrum and milk synthesis, as well as on immunological parameters in offspring. Pregnant ewes were fed to 100% of nutrient requirements throughout pregnancy and lactation (Control) or to 50% during lactation (R1) or during the last 20 days of pregnancy and lactation (R2). Colostrum samples were collected 3 and 18h after parturition and thymus glands were obtained from 5-month-old offspring. Lamb birthweight did not differ between groups, whereas growth rate was significantly lower in males in the R1 group and in females in both undernourished groups. There was a significant reduction in lactose percentage in the 18-h colostrum of the R2 group. The IgG concentration, as a percentage of protein, was significantly increased in 3-h colostrum samples of the R2 group. Quantitative polymerase chain reaction analysis revealed a significant increase in the expression of Toll-like receptor (TLR) 2, TLR4 and TLR9 in the thymus gland of female lambs in both undernourished groups. In conclusion, early life nutritional imbalances may impact on immune system function in later life due to programming effects.

PPO.03 Effects of maternal nutrition and ruminal-protected arginine supplementation on offspring growth

Our hypothesis was that arginine supplementation would overcome the negative effects of restricted maternal intake during the last two-thirds of gestation on offspring growth. Multiparous, Rambouillet ewes (n = 32)...

Review: Water stress in sheep raised under arid conditions

Chedid, M., Jaber, L. S., Giger-Reverdin, S., Duvaux-Ponter, C. and Hamadeh, S. K. 2014. Review: Water stress in sheep raised under arid conditions. Can. J. Anim. Sci. 94: 243–257. Sheep breeds which are indigenous to arid and semi-arid regions are known for their ability to adapt to rustic environments, to climatic variations as well as to shortages in resources. Water scarcity, often combined with heat stress, is a common challenge facing these animals, causing physiological perturbations and affecting the animal's productivity. This review reports the effect of different forms of water stress on physiological indicators, blood parameters, thermoregulation and immunological status in sheep. Although the breed effect may be significant, the following are generally observed common responses: drop in feed intake and weight loss, increase in evaporative cooling through panting, production of a small volume of highly concentrated urine, haemoconcentration, high blood osmolality, and immunosuppression. Prolonged water shortage may affect lamb birth weight and survival, and lead to a decrease in milk production, especially in non-adapted breeds, which could lead to important economic losses, as reported in heat-stressed sheep husbandries. Novel stress alleviation approaches are also presented, such as vitamin C supplementation.

6.8 Hepatic IGF1 DNA methylation and mRNA expression are influenced by gender but not by prenatal growth restriction in the young lamb

IntroductionEarly postnatal growth and body composition are variously influenced by fetal nutrient supply and gender. Thus relative to normal birth weight lambs (N), those categorised as fetal growth restricted (FGR,...

The influence of dietary manipulations and gastrointestinal nematodes on twin-bearing merino ewes and determinants of lamb survival

The aim in this experiment was to examine the effects of prepartum supplementation, fat score (FS) and gastrointestinal nematode (GIN) infection on whole-body composition of twin-bearing and rearing Merino ewes. These effects were then related to lamb birth weight, ewe colostrum yield and foetal brown adipose tissue stores as principal determinants of neonatal mortality. The experiment was conducted as a 3×2×2 factorial design from day (d) −98 to weaning at d 55 (relative to the mid-point of lambing, d 0). There were three infection groups (uninfected, 1000 Haemonchus contortus L3/week, or 6000 Trichostrongylus colubriformis L3/week), two levels of nutrition from d −97 to d −52 (designed to achieve FS targets of 2 and 4) and two prepartum supplementation groups (0 or 200g/d cottonseed meal; CSM) from d −52 to d −12. Ewes managed to higher FS during mid-pregnancy were 8kg heavier and 1.3 FS units greater (p<0.001) by d −54, 4kg (p=0.049) and 0.6 FS units (p<0.001) by d −12, but did not differ from low FS ewes by d 53. Carcass fat, omental fat and lean muscle mass (all p<0.001) were greater in high FS ewes at d −12 but not at d 55. Neither colostrum yield, milk yield or lamb birth weight differed between FS groups but lambs born to low FS ewes had greater (p=0.050) brown adipose tissue reserves. Prepartum supplementation increased ewe live weight (p=0.049), carcass fat (p=0.032) and muscle (p=0.013) by parturition and lamb birth weight (p=0.012), with the benefit being greatest for low FS ewes. T. colubriformis infection reduced lamb birth weight and H. contortus reduced ewe live weight, milk yield and lamb growth to weaning. These results highlight the effectiveness of providing adequate nutrition to twin-bearing Merino ewes in late pregnancy and controlling GIN infections, especially where ewe FS has fallen below Australian industry targets.

Genetic parameters for lamb birth weight, survival and death risk traits.

This paper reports genetic parameters for lamb survival and mortality traits on sheep farms in New Zealand. Lamb survival and mortality records were obtained from 38 flocks (103,357 lambs) from 5 yr of lambing data (2007 to 2011) and include many breeds and their crosses (predominantly Romney, Perendale, Coopworth, and Texel). A number of models were tested, all including environmental weather effects and investigating the random environmental effect of dam and litter (dam/year) as well as logit transformation for binary traits. Total heritability (direct + maternal) estimates were low for lamb viability at birth (0.01), lamb death risk to dystocia (0.01), and lamb death risk to starvation exposure (0.01) from birth to 3 d of age in an analysis accounting for direct and maternal genetic effects and the maternal environmental effects. Lamb survival heritabilities reported are very low (total heritabilities range from 0.02 to 0.06). The total heritabilities for the lamb death risk traits are lower than reported estimates of survival to 3 d of age or to weaning suggesting selection for the postmortem traits are not warranted at this time within these flocks. The total heritability for lamb birth weight was moderate (0.38) and the genetic correlations with the lamb death risk traits suggested that directional selection on lamb birth weight would have an effect on survival, although it is likely to have a nonlinear effect and therefore an optimum birth weight at which survival is maximized. This study has also shown that the total heritabilities may be overestimated when not accounting for maternal genetic and environment effects and in particular not accounting for the random environmental effect of litter (dam/year).

Uteroplacental Adenovirus Vascular Endothelial Growth Factor Gene Therapy Increases Fetal Growth Velocity in Growth-Restricted Sheep Pregnancies

Fetal growth restriction (FGR) occurs in ∼8% of pregnancies and is a major cause of perinatal mortality and morbidity. There is no effective treatment. FGR is characterized by reduced uterine blood flow (UBF). In normal sheep pregnancies, local uterine artery (UtA) adenovirus (Ad)-mediated overexpression of vascular endothelial growth factor (VEGF) increases UBF. Herein we evaluated Ad.VEGF therapy in the overnourished adolescent ewe, an experimental paradigm in which reduced UBF from midgestation correlates with reduced lamb birthweight near term. Singleton pregnancies were established using embryo transfer in adolescent ewes subsequently offered a high intake (n=45) or control intake (n=12) of a complete diet to generate FGR or normal fetoplacental growth, respectively. High-intake ewes were randomized midgestation to receive bilateral UtA injections of 5×10¹¹ particles Ad.VEGF-A165 (n=18), control vector Ad.LacZ (n=14), or control saline (n=13). Fetal growth/well-being were evaluated using serial ultrasound. UBF was monitored using indwelling flowprobes until necropsy at 0.9 gestation. Vasorelaxation, neovascularization within the perivascular adventitia, and placental mRNA expression of angiogenic factors/receptors were examined using organ bath analysis, anti-vWF immunohistochemistry, and qRT-PCR, respectively. Ad.VEGF significantly increased ultrasonographic fetal growth velocity at 3-4 weeks postinjection (p=0.016-0.047). At 0.9 gestation fewer fetuses were markedly growth-restricted (birthweight >2SD below contemporaneous control-intake mean) after Ad.VEGF therapy. There was also evidence of mitigated fetal brain sparing (lower biparietal diameter-to-abdominal circumference and brain-to-liver weight ratios). No effects were observed on UBF or neovascularization; however, Ad.VEGF-transduced vessels demonstrated strikingly enhanced vasorelaxation. Placental efficiency (fetal-to-placental weight ratio) and FLT1/KDR mRNA expression were increased in the maternal but not fetal placental compartments, suggesting downstream effects on placental function. Ad.VEGF gene therapy improves fetal growth in a sheep model of FGR, although the precise mechanism of action remains unclear.

Mineral supplementation of lambing ewes grazing dual-purpose wheat

Lambing ewes were grazed on dual-purpose wheat in two experiments in 2010 and 2011 with or without access to a mineral supplement. The calcium, magnesium and sodium content of wheat forage was below the requirements of ewes during late pregnancy and lactation; however, no clinical cases of hypocalcaemia or hypomagnesaemia were observed in either experiment. Blood serum assays identified eight hypocalcaemic ewes and one hypomagnesaemic ewe in Experiment 1, and one hypocalcaemic ewe in Experiment 2, and the provision of a mineral supplement comprising of magnesium oxide, calcium carbonate and coarse salt had no effect on blood magnesium, total calcium, phosphorus or sodium. Lamb birthweight and survival were not affected by provision of the mineral supplement in either experiment; however, the growth rate to marking (mean 38 ± 10 days of age) of twin-born lambs was higher in Experiment 1 when the supplement was provided to ewes grazing wheat (259 vs 243 g/head.day; P = 0.002).

The influences of live weight and body condition score of ewe lambs from breeding to lambing on the live weight of their singleton lambs to weaning

One of the limiting factors to the adoption of breeding 7-month-old ewes is that their lambs are lighter at birth and weaning than lambs born to mature ewes. The present study tested the hypothesis that the live weight and body condition score of 7-month-old ewes at breeding and during pregnancy would influence the live weight of their singleton-born lambs to weaning. Data was collected on one commercial sheep farm from 591 ewes across two years. In 2011 and 2012, during pregnancy the ewes gained 14.6 and 10.1kg of total live weight, respectively. Multiple regression analysis indicated that live weight of ewes at breeding had a positive effect (P<0.05, 0.03±0.02kg of birth weight per kg of ewe live weight) on lamb birth weight while ewe live weight in late pregnancy had a negative effect (P<0.05, −0.03±0.01kg of birth weight per kg of ewe live weight). Overall the R-square of the model for lamb birth weight was small (R2=0.01) indicating, that live weight of the ewe was not a major contributor to the live weight of lambs at birth. The live weight of ewes in late pregnancy had a positive impact on both the live weight of lambs at approximately 18 days of age and at weaning (P<0.05, 0.05±0.02 and 0.08±0.03kg of lamb live weight per kg of ewe live weight, respectively) but again the R2 value for the multiple regression was small (0.01). Body condition score of the ewe at breeding and in mid-pregnancy had no effect (P>0.05) on lamb birth weight. In contrast ewes with body conditions scores of 3.5 and 4.0 or greater in late pregnancy gave birth to lighter lambs (4.9±0.1 and 4.7±0.2kg, respectively) than ewes with body condition scores of 2.5 or less (5.3±0.1kg) or 3.0 (5.2±0.1kg, P<0.05). There was no effect (P>0.05) of ewe body condition score on lamb live weight at approximately 18 days of age or at weaning. Therefore, under the conditions of this study ewe live weight and condition score during pregnancy had a minimal effect of lamb live weight from birth to weaning.

Increasing weight gain during pregnancy results in similar increases in lamb birthweights and weaning weights in Merino and non-Merino ewes regardless of sire type

Birthweight is the single largest determinant of survival in lambs and can be predicted from ewe liveweight at conception and liveweight changes during pregnancy. These prediction equations are known for Merino ewes, but it is unknown if they are applicable to non-Merino breeds. We tested the hypothesis that increasing conception weights of ewes will increase the birthweights, survival to weaning and weaning weights of their lambs, irrespective of ewe or sire breed, but that non-Merino lamb birthweights would be less responsive than Merino lamb birthweights, to changes in ewe liveweights during pregnancy. Ewe liveweight, lamb birth and weaning weight records from Merino sires mated to Merino ewes (MM), Border Leicester Merino (Maternal) sires mated to Merino ewes, Poll Dorset or Suffolk (Terminal) sires mated to Merino ewes (TM), and Terminal sires mated to Border Leicester Merino ewes (TMAT) were analysed from the 2007 to 2011 lambings of eight information nucleus flocks. Lamb birthweights increased by 0.032 ± 0.0012 kg from MM ewes and 0.024 ± 0.0026 kg from TMAT ewes with every 1-kg increase in conception weight (P &lt; 0.001). Irrespective of breed, for every 1-kg increase in liveweight change during early and late pregnancy, lamb birthweights increased by 0.021 ± 0.0019 kg and 0.034 ± 0.0019 kg and weaning weights by 0.26 ± 0.013 kg and 0.09 ± 0.011 kg, respectively (P &lt; 0.001). Survival to weaning of single, twin and triplet lambs was highest for lambs from TMAT ewes (89.3% ± 1.25, 84.6% ± 1.49 and 73.4% ± 2.35) and lowest for TM ewes (80.2% ± 1.89, 72.8% ± 2.09 and 57.4% ± 2.98; P &lt; 0.001). Coefficients relating ewe liveweight change during pregnancy to lamb birthweights are similar for Merino and Maternal ewes, however conception weights of Maternal ewes are significantly heavier than Merino ewes when run together, and lamb birthweights from Maternal ewes are less responsive to ewe conception weights. The coefficients reported in this paper will enable development of optimum management guidelines for single-, twin- and triple-bearing Maternal ewes.

Effect of selenium on the reproductive performance of ewes and white muscle disease in lambs

A study using 60 Awassi ewes fed either a control (unsupplemented) diet or one containing selenium-enriched yeast (Selplex™, Alltech Incorporated, USA) at a dose rate of 0.2 mg/kg diet was conducted to investigate the effects on white muscle disease occurrence in progeny. The effects of organic selenium on oestrus, fertility, lamb birth weights, weaning weights and rates of white muscle disease were recorded. There was no effect of organic selenium supplementation on pregnancy rates as recorded by ultrasound at 40 and 80 days after mating (P>0.05). Likewise, there were no significant differences in lambing, single or twinning rates between the control ewes and those receiving organic selenium. Birth and weaning weights were not significantly different in either single or twin lambs from either control or Se-supplemented ewes. However, the Se-supplemented ewes gave birth to lambs which had significantly less incidence of white muscle disease (37.5% versus 3.3%; P

Relationship between birth weight and body growth characteristics of lambs

Research was carried out in population of R2 generation Pirot pramenka x Pirot improved sheep during period of three years. Lambs were divided into three groups: I from 2.5 kg to 3.5 kg; II from 3.6 kg to 4.5 kg; III from 4.6 kg to 5.5 kg. Weight of lambs was controlled at birth, with 30, 60 and 90 days of age. Average body weight at birth of the tested lambs was 3.35 kg in the first group, 4.30 kg in the second group and 5.06 kg in the third group. At 30 days of age, the body weight of the lambs was 10.19 kg in the first group, 11.39 kg in the second and 12.49 kg in the third group. All these differences in body weight of lambs at birth were statistically highly significant (P_ 0.01). With 60 days of age, average body weight was 16.48 kg in the first group, 19.01 kg in the second and 20.49 kg in the third group. Differences between groups of lambs at this age were statistically very significant (P_0.01).On the end of experiment at 90 days of lambs age, we have found the following values of the body weight of lambs: 26.35 kg in the first group, when the second 30.49 kg and 28.93 kg in the third group. Differences between groups of lambs at this age were statistically very significant (P_0.01). At the age of 90 days maximum weight of the body was in the second group of lambs, or a group which body weight at birth occupied the mean of the population. Correlations between body weights of lambs vary from weak to midsized values. The highest values of correlation coefficients were found between body weight at birth and weight of lambs at 30 days of age.

Environmental influences on growth traits of Nali sheep

The objective of this study was to evaluate the effect some environmental factors on birth weight, weaning weight and daily gain weight in Nali lambs. Data from 77 records were analysed. Results showed that birth weight (BW), weaning weight (WW), average daily gain at pre-weaning (ADG1) and average daily gain at post-weaning (ADG2) were influenced by year and season of lambing, sex of lambs, and parity of dam. Birth weight of lambs born during the year 2008 was significantly heavier (2.49±0.04 kg) than year 2007 (2.21±0.05 kg). Also WW and ADG1 in 2008 were significantly (P

Reproductive Performances of Indigenous Ewes in Bangladesh

The ewes were randomly divided into controlled and supplemented group to determine the reproductive performances of indigenous ewes in Bangladesh. Ewe lambs on supplemented group was growing faster and reached puberty at significantly (p 0.05) different between the two groups. The stage of the estrous cycle was determined by observing exfoliated vaginal cells in both the groups. Average progesterone concentration was significantly different (p<0.01) among days of the oestrous cycle. Progesterone concentration was <1.0 ng/ml on day of estrus, rose steadily to peak on days 10 and followed by a rapid decline on day 15 in both group. The nutritional supplement did not improve sexual behaviors. The pregnancy rates were 83.33 and 100% in controlled and supplemented groups. The gestation length varied from 141 to 145 days. The post partum onset of estrus was significantly shorter in supplemented group than controlled group (p<0.05). The lambing rates, litter size and lamb survival rate were 75 and 100%, 1.22±0.44 and .1.58±0.67 and 91.67 and 100%, in controlled and supplemented group, respectively. Mean birth weights of lambs were 1.00±0.30 and 1.33±0.25kg in controlled and supplemented group, respectively. The pre-weaning average daily gain of lambs were significantly different (p<0.01) between two groups. The present study indicates the influence of nutrition on reproductive performances of ewes that may increase and improve the sheep production.

The Effects of Dose of Pregnant Mare Serum Gonadotropin (PMSG) on Reproductive Performance of Algerian Rembi Ewes during Seasonal Anoestrus

The current study was designed to evaluate the effect of different doses of pregnant mare serum gonadotropin (PMSG) on reproductive performance of Rembi ewe during seasonal anoestrus. A total of 120 sheep and 12 rams of Rembi ewe lamb were used in this experiment. Vaginal sponges containing 40 mg of fluorogestone acetate were inserted into the vagina of the ewes. The sponges were withdrawn on day 7 and 300 IU of PMSG (group 1, n=30, 500 IU of PMSG (group 2, n=30) and 700 IU of PMSG (group 3, n=30) were injected intramuscularly. The rates of fertility in groups 2, 3, 4 and the control group were found as 86,2%, 79,3%, 72,4%, and 44,8%, respectively. Fecundity rates were 1.14%, 1.20%, 1.03% and 0.48% in groups 2, 3, 4 and the control group, respectively. The rates of prolificacy in groups 2, 3, and 4 which received different doses of PMSG and the control group were found as 1.08%, 1.52 %, 1.43%, and 1.08%, respectively. Lambing rates were obtained as 67.5%, 77.5%, 77.5% and 58.8% in groups1, 2, 3 and in control group, respectively. The effect of the hormonal treatments on the birth weight of lambs averaging 1.90 ± 0.16, 2.60 ± 0.11 and 3.25 ± 0.19 kg respectively. The application of 500 IU PMSG was rather more effective than injections of 300 IU and 700 IU in Rembi ewes being outside the breeding season.

Pregnancy nutrition does not influence lamb liveweight in developmentally programmed ewes

In sheep, maternal nutrition can affect the offspring’s milk production at its first lactation and the grand-offspring’s liveweight to weaning. However, this apparent developmental programming effect on milk production and grand-offspring liveweight has not persisted. Therefore, the aim of the present study was to determine if nutrition of the programmed ewe in mid- to late pregnancy affected this response. Developmentally programmed ewes (G1) that had been born from dams (G0) offered submaintenance, maintenance or ad libitum feeding levels from Day 21 to Day 50 of pregnancy and then either pregnancy maintenance or ad libitum to Day 140 were used for this study. These ewes were offered one of two pastoral-based pregnancy nutritional treatments (controlled vs unrestricted) from Day 76 of pregnancy until lambing. Pre- and post-herbage masses of the unrestricted treatment (2181 ± 47.6 and 1431 ± 24.6 kg DM/ha, respectively), were greater (P &lt; 0.05) than the controlled treatment (1164 ± 31.6 and 819 ± 16.0 kg DM/ha, respectively). At Day 71 of pregnancy, there were no differences (P &gt; 0.05) in G1 liveweight (70.2 ± 0.8 vs 70.3 ± 0.8 kg for controlled and unrestricted feeding, respectively), or body condition scores (2.5 ± 0.06 vs 2.5 ± 0.05) between pregnancy nutritional treatments. In late pregnancy, unrestricted G1 ewes were heavier (P &lt; 0.05, 97.4 ± 1.0 vs 86.8 ± 1.0 kg) and had greater (P &lt; 0.05) body condition scores (3.4 ± 0.06 vs 2.5 ± 0.06) and back-fat depths (8.0 ± 0.3 vs 5.9 ± 0.03 mm) than controlled nutritional treatment ewes. There were no interactions (P &gt; 0.05) between grand-dam feeding levels and ewe nutritional treatment on lamb (G2) liveweights at birth or in lactation. This indicates that under the conditions of the present study, nutrition of the G1 ewe did not affect the expression of the developmental programming effect. Further studies might be warranted to determine the causes of this inconsistency in grand-offspring liveweight. Nutrition of the G1 ewe had a minor effect (P &lt; 0.05) on G2 lamb birthweight and liveweight in early lactation but not (P &gt; 0.05) in late lactation or on lamb survival. These findings indicate there is no little to no benefit to the lamb until weaning from offering ewes pre- and post-grazing masses above ~1200 and 800 kg DM/ha, respectively, in mid- to late pregnancy.

Effect of body condition score and body weight of Sanjabi ewes on immune system, producti ve and reproducti ve performance

Total 80 Sanjabi ewes (2–5 years old and 50–85 weight domain) were selected in animal unit of Mehregan farm. The ewes were divided to 4 treatment groups according to body condition score of (2, 2.5, 3, 3.5 ≤). Blood samples were collected from non-pregnant ewes, then after mating, two weeks before expected lambing and at lambing day. Blood samples of newborn lambs were also taken from the jugular vein at birth and 7 days of age. The reproductive parameters such as number of lambs born per lambing, kg of lambs born per ewes mating, pregnancy period and lamb birth weight were determined. Some blood metabolites such as glucose, total protein, albumin and globulin were determined. The white blood cell and differential leukocyte counts were also measured. The result of this experiment indicated that BCS = 3 had a significant effect (P &lt; 0.05) on the kg lambs born per ewes. Ewes with BCS = 3 had a better performance in the percentage of lambs born per ewes at mating, while the lambing rate reduced in ewes with BCS of 3.5 or more. Birth weight of lambs was significantly affected by BCS of their ewes (P &lt; 0.05). There was a significant effect of BCS on plasma FSH concentration in ewes with BCS more than 3 but no significant difference was seen in blood metabolite in this study. Colostrum productions and the lamb birth weights were affected by body condition score of ewes. The white blood cell counts, neutrophils and lymphocytes counts did not change between ewes and lambs. It is concluded that BCS had a significant effect on kg lambs born per ewes, birth weight of lambs, lambs weaning weight and colostrum productions (P &lt; 0.05) and the score of 3 at mating time could optimize profitability of Sanjabi ewes.