Lamb Birth Weight Research Articles

The effect of non-genetic factors on the birth weight of Romanov sheep

The aim of this study was to analyse the non-genetic factors influencing the birth weight of Romanov lambs, and to determine which of them may be a useful source of information in the selection of female lambs for replacement. The study included 1712 lambs born in the period from 2016 to 2019. The linear model used in birth weight estimation included: birth type, sex, parity, year of birth, season of birth, and breeding group as fixed factors. Year of birth x season of birth interaction was also included in the model. All factors, except the season of birth, significantly affected birth weight (P<0.05). Birth weight decreased significantly (P<0.05) with increasing birth type and singles, twins, triplets and quadruplets weighing 4.11 ± 0.07, 3.56 ± 0.05, 3.07 ± 0.05 and 2.66 ± 0.08 kg, respectively. Male lambs (3.44 ± 0.05 kg) were significantly (P<0.05) heavier than female lambs (3.25 ± 0.05 kg). The lightest lambs (2.99 ± 0.05 kg) were born in the first litter, after which the birth weight gradually increased up to the sixth litter (3.54 ± 0.10 kg). Litter weight showed a nonlinear increase with an increase in birth type (P<0.05). The birth weight of female lambs from litters of twins and triplets with different ratios of male and female lambs did not differ significantly (P>0.05). Variations in birth weight are influenced by non-genetic factors, with birth type, sex, and parity being the most important. These factors should be considered in breeding and selection programs for lamb meat production, where fertility and growth traits have the key role.

Intermittent maternofetal oxygenation during late gestation improved birthweight, neonatal growth, body symmetry, and muscle metabolism in intrauterine growth-restricted lambs.

In humans and animals, intrauterine growth restriction (IUGR) results from fetal programming responses to poor intrauterine conditions. Chronic fetal hypoxemia elevates circulating catecholamines, which reduces skeletal muscle β2 adrenoceptor content and contributes to growth and metabolic pathologies in IUGR-born offspring. Our objective was to determine whether intermittent maternofetal oxygenation during late gestation would improve neonatal growth and glucose metabolism in IUGR-born lambs. Pregnant ewes were housed at 40 °C from the 40th to 95th day of gestational age (dGA) to produce IUGR-born lambs (n = 9). A second group of IUGR-born lambs received prenatal O2 supplementation via maternal O2 insufflation (100% humidified O2, 10 L/min) for 8 h/d from dGA 130 to parturition (IUGR+O2, n = 10). Control lambs (n = 15) were from pair-fed thermoneutral ewes. All lambs were weaned at birth, hand-reared, and fitted with hindlimb catheters at day 25. Glucose-stimulated insulin secretion (GSIS) and hindlimb hyperinsulinemic-euglycemic clamp (HEC) studies were performed at days 28 and 29, respectively. At day 30, lambs were euthanized and ex vivo HEC studies were performed on isolated muscle. Without maternofetal oxygenation, IUGR lambs were 40% lighter (P < 0.05) at birth and maintained slower (P < 0.05) growth rates throughout the neonatal period compared with controls. At 30 d of age, IUGR lambs had lighter (P < 0.05) hindlimbs and flexor digitorum superficialis (FDS) muscles. IUGR+O2 lambs exhibited improved (P < 0.05) birthweight, neonatal growth, hindlimb mass, and FDS mass compared with IUGR lambs. Hindlimb insulin-stimulated glucose utilization and oxidation rates were reduced (P < 0.05) in IUGR but not IUGR+O2 lambs. Ex vivo glucose oxidation rates were less (P < 0.05) in muscle from IUGR but not IUGR+O2 lambs. Surprisingly, β2 adrenoceptor content and insulin responsiveness were reduced (P < 0.05) in muscle from IUGR and IUGR+O2 lambs compared with controls. In addition, GSIS was reduced (P < 0.05) in IUGR lambs and only modestly improved (P < 0.05) in IUGR+O2. Insufflation of O2 also increased (P < 0.05) acidosis and hypercapnia in dams, perhaps due to the use of 100% O2 rather than a gas mixture with a lesser O2 percentage. Nevertheless, these findings show that intermittent maternofetal oxygenation during late gestation improved postnatal growth and metabolic outcomes in IUGR lambs without improving muscle β2 adrenoceptor content.

Influence of maternal and additive genetic effects on lamb survival in Harnali sheep.

Lamb survival is a critical aspect in the sheep industry as it increases the chances of economic gain in the flock. The objective of the current study was to assess the incidence of lamb mortality in Harnali sheep and to estimate maternal and additive genetic effects of lamb survival using the data of 2057 lambs born to 134 sires and 623 dams for the period of 20years (2001-2020). The genetic evaluation was carried out using threshold animal models comprising direct and maternal effects using THRGIBBS1F90 and POSTGIBBSF90 programs. Cumulative mortality (95% CI (confidence interval)) for the S1 (lambs which died up to weaning age), S2 (lambs which died from birth to 6months of age) and S3 (lambs which died from birth to 12months of birth) groups was 8.41 (7.21-9.61), 14.10 (12.59-15.60) and 17.70 (16.05-19.34) %, respectively. The logistic regression analysis revealed significant (p<0.05) influences of non-genetic factors and indicated that the female lambs, heavier dam and higher birth weight of lamb were associated with better survival as compared to their counterparts. The estimates of direct additive heritability for S1, S2 and S3 were 0.04±0.01, 0.07±0.03 and 0.11±0.04, respectively. In addition to this, significant influences of the maternal permanent environmental effects were observed for lamb survival up to weaning as well as six months of age. Thus, the present findings suggest that lamb survival could be improved through better management practices but consideration of maternal permanent environmental effects is important for initial survival of the lamb.

Perinatal complications and maximising lamb survival in an adolescent paradigm characterised by premature delivery and low birthweight.

The competition for nutrients in overnourished and still-growing adolescent sheep negatively impacts gestation length, colostrum supply and lamb birthweight, all of which may affect neonatal morbidity and survival to weaning. Herein perinatal complications and the requirement for supplementary feeding were analysed in relation to gestational-intake, and the degree of premature delivery and prenatal growth-restriction exhibited. Pregnancies were established by embryo transfer and the mean/standard deviation (SD) gestation length and birthweight of the optimally-fed control group (n = 100) was used to define early delivery and reduced birthweight categories (1.5 and 3.0 SDs below the control mean for each aspect). Control lambs were largely delivered at term (94%), and had a normal birthweight (92%), while very preterm (≤139days, 18.5%) and preterm delivery (140-142days, 54.8%), extremely low birthweight (ELBW; females ≤2838g and males ≤3216g, 21.1%) and low birthweight (LBW; females 2839 to ≤4001g and males 3217 to ≤4372g, 32.2%), were common in the overnourished group (n = 270, P<0.001). Accordingly, overnourished dams were more likely to lamb without assistance while the incidence of major dystocia was greater in controls. Initial lamb vigour at birth was independent of gestational-intake, delivery or birthweight category but both ELBW and very premature lambs required more assistance with feeding in the first 24h postnatal, primarily reflecting low colostrum availability. Indeed, relative to normal, ELBW lambs had a greater risk of experiencing mismothering, and enhanced likelihood of requiring supplementary feeding throughout the neonatal period (P<0.001). ELBW lambs also had a greater possibility of respiratory issues at birth (P<0.01) and renal complications (P<0.001), while very preterm delivery was associated with an increased risk of gastrointestinal tract problems (P<0.01). In spite of these complications, all-cause mortality was low (5.4%) suggesting that our proactive neonatal care regime can overcome many of the issues associated with extreme prematurity and low birthweight.

Melatonin treatment during late gestation of undernourished ewes: lamb body temperature and mother–young behaviours after birth

Context In extensive grazing sheep systems, pregnant ewes undergo periods of undernutrition because gestation coincides with winter when natural pasture is of lowest quantity and poorest quality. The lamb’s weight and thermoregulatory capacity, and the ewe–lamb bond at birth, may be compromised. Maternal melatonin treatment during gestation may reverse these effects. Aim The aim was to determine the effects of melatonin treatment of single-lambing, undernourished ewes during the last third of gestation on lamb birthweights and body temperatures, and on ewe–lamb interactive behaviour after birth. Methods At Day 100 of gestation, 39 single-bearing ewes received a subcutaneous melatonin implant, and 54 ewes served as controls with no implant. Throughout gestation, the ewes remained under extensive conditions grazing on natural pasture. Measurements were made of lamb birthweight, body temperatures (surface temperature by infrared thermography and rectal temperature), and ewe–lamb behaviours during a handling test at 6–17 h after lambing. Key results There was no effect of melatonin treatment on lamb birthweight or rectal temperature, or on ewe–lamb interaction behaviours. Hip minimum surface temperature was greater in lambs from melatonin-treated ewes than lambs from control ewes (21.2°C ± 0.9°C vs 18.8°C ± 0.8°C; P = 0.05), and there was a similar trend for hip mean surface temperature (24.6°C ± 0.9°C vs 22.3°C ± 0.7°C; P = 0.06). Rump surface temperatures were greater in male than female lambs: maximum (27.9°C ± 1.2°C vs 22.9°C ± 1.2°C; P = 0.01), minimum (22.2°C ± 1.5°C vs 16.7°C ± 1.5°C; P = 0.02) and mean (25.4°C ± 1.3°C vs 20.5°C ± 1.3°C; P = 0.02). Conclusion Melatonin treatment during the last third of ewe pregnancy slightly enhanced the surface temperature of lambs at birth but did not influence ewe–lamb interaction behaviour after birth (i.e. after establishment of the ewe–lamb bond). Implications Further study in more depth is warranted into the possible effects of maternal supplementation with commercial melatonin implants on lamb development, thermoregulatory capacity, behaviour and survival rates in extensive grazing systems, including the effect on ewe–lamb behaviours immediately after birth for both singletons and twins.

Voluntary intake, milk and colostrum production and lamb growth when ewes are fed high-NaCl diets during pre- and post-lambing

Nutritional requirements at the end of gestation in ewes carrying multiple fetuses are rarely fully met in pasture production systems. Thus, concentrate feeds entail an alternative for increasing herd productivity. However, daily offer of complementary feed in extensive livestock production systems is not always possible due to climatic or geographic constraints or to labor shortages. One alternative is to offer large amounts of concentrate feed with the addition of NaCl that limits voluntary consumption, eliminating the need for daily supplement delivery. Our objective was to evaluate the effect of high salt levels added to concentrate feed on pre- and post-lambing twin-gestating ewes and their responses on feed intake, colostrum and milk production and composition, plasma biochemical profile variation and lamb growth. Twenty-four adult Corriedale females were housed in individual stalls and divided into four treatments: S13: ad libitum concentrate feed plus 13 % of salt; C13: the same amount of concentrate feed consumed by S13 ewes the day before, but without salt; S17: ad libitum concentrate feed with 17 % of salt, and C17: the same amount of concentrate feed consumed by S17 ewes the day before, but without salt. Fresh water and forage were offered in ad libitum amounts. Treatments were applied in the period of highest ewe nutrient demand, from day 123 of pregnancy to day 21 of lactation. The four percentage points in salt content resulted in a decrease of organic matter daily intake of concentrate (23 % of reduction in pre-lambing and 35 % of reduction in post-lambing for S17 relative to S13; P = 0.0134 and P = 0.0164, respectively). Lamb birth weights were similar between S13 and C13 (P = 0.1002) and between S17 and C17 (P = 0.8449) treatments. Colostrum and milk production did not differ between S13 and C13 (P = 0.9776 and P = 0.8928, respectively) or between S17 and C17 groups (P = 0.4943 and P = 0.7705, respectively). Plasma insulin, hematocrit and total protein levels were not influenced by the treatments and these parameters remained within normal physiological limits. Thus, the addition of 13 or 17 % of salt to concentrate feed did not affect the reproductive capacity of ewes or offspring growth, showing that ewes are able to withstand high doses of NaCl and supporting the potential of salt as a limiter of voluntary intake in pre- and post-lambing diets.

Factors affecting birth weight and pre-weaning growth rate of lambs from the Icelandic sheep breed

In Iceland, the sheep production year is characterized by lambing in May, weaning and slaughtering in September and October. Our hypothesis is that modelling interrelationships of production parameters will aid in controlling variation in important outputs like weaning weight. We analyzed data from twelve production years in our experimental farm with total records of 9661lambs born to 1847 dams. In the whole dataset, 7.4 % of the lambs were born as singles, 78.1 % as twins, 13.7 % as triplets and 0.8 % as quads. Surrogate mothers fostered 5.5 % of the lambs.

İkizliğin İleri gebe koyunlar ve bunların kuzularında mineral madde, immunglobulin G ve kuzu doğum ağırlığı üzerine etkisi

The aim of this study was to investigate the effects of twinship on the mineral matter, immunoglobulin G (IgG), and lamb birth weight in late pregnant ewes and their lambs. The material of the study consisted of the 18 Kıvırcık breed ewes, which were 130-150 days pregnant, and their 27 newborn lambs. The ewes included in the study were divided into two groups by ultrasound as those carrying a single pregnancy (n=9) and a twin pregnancy (n=9). Body Condition Scores (BCS) were determined and then their blood samples were taken. The lambs born from these ewes were weighed with precision scales as soon as they were born, and blood samples were taken 24 hours after birth. Mineral substance determination from blood samples was made by ICP-OES, and IgG determination was made by ELISA. It was found that serum IgG and mineral matter levels were not affected by twinship in ewes (p&gt;0.05). Calcium (Ca) level was significantly higher in twin lambs compared to single lambs (p0.05). Total protein and globulin values were significantly higher in single lambs than twin lambs (P

Maternal lysine, methionine and choline supplementation in twin-bearing Merino ewes during mid-to-late gestation does not alter pregnancy outcomes or progeny growth and survival

High twin lamb mortality in Merino sheep is a major cost for the Australian wool and sheep meat industry. Most lambs die within three days of birth due to low birthweight and/or complications arising during parturition. Maternal arginine supplementation can potentially increase birthweight by improving utero-placental haemodynamics; but availability and cost of rumen-protected arginine are barriers. Therefore, we sought to increase circulating concentrations of arginine, lamb birthweight and survival by supplementing twin-bearing Merino ewes with lysine, methionine and choline from day 80 of gestation (dG 80) to parturition. Each day, ewes were individually fed a supplement (barley, pea, pollard and molasses) with addition of either 14 g lysine, 7 g methionine and 7 g choline (amino acid; AA; n = 48); or no amino acids (control; CTL; n = 48). Supplementation did not alter circulating amino acid profiles in ewes at dG 120. Parturition difficulty of ewes and meconium staining of lambs did not differ between AA and CTL groups. Rectal temperatures during the first 24 h of life and serum IgG concentrations (indicative of colostrum intake) at 24 h after birth were similar in lambs born to AA and CTL ewes. AA supplementation did not alter lamb weights from birth to weaning (~three months of age), or lamb survival to weaning (CTL: 75%; AA: 84.8%, P > 0.05). The lack of response to maternal supplementation with this combination of rumen-protected lysine, methionine and choline suggests that alternate strategies are needed to increase maternal arginine abundance and twin lamb survival.

Effects of Environmental Factors Growth Traits of Akkaraman Sheep in Çankırı Province

Small ruminants are important contributors of food supply chains throughout the world. In this study, characterization of distributions of birth weight, weaning weight, average daily gain and Kleiber ratio as well as estimation of effects of certain environmental factors on these traits were aimed in Akkaraman sheep raised around Çankırı province. For this purpose, the linear mixed model was fitted to estimate the effect of factors and to obtain the least square means for the traits. The effect of all studied fixed factors on birth weight (BW), weaning weight (WW), average daily weight gain (ADWG) and Kleiber ratio (KR) were found to be significant. The male lambs have more BW and WW than female lambs. The least square mean of ADWG for female lambs was found higher than male lambs. Additionally, the least square mean of the pre-weaning growth traits of single-born lambs were found to be higher than that of twin-born lambs. The birth weights of lambs born in January and February were higher than March. In general, the study reported that pre-weaning growth traits were affected by several environmental factors, which can be used for herd management practices aiming for higher productivity in Akkaraman sheep.

Effects of mid-gestational l-citrulline supplementation to twin-bearing ewes on umbilical blood flow, placental development, and lamb production traits.

The objective of the study was to examine how l-citrulline supplementation to ewes during mid-gestation influences placental activity, placental blood flow, lamb body weight, and carcass characteristics. Two studies were completed. A pharmacokinetic study to compare circulating plasma amino acid concentrations after a single intravenous injection of 155 µmol/kg BW l-citrulline or after an isonitrogenous amount of l-alanine (control; 465 µmol/kg BW). Increases (P < 0.05) in circulating citrulline concentrations were detected for 8 h after l-citrulline injection versus the control. Similarly, increases (P < 0.05) in circulating arginine concentrations were detected for 24 h after l-citrulline treatment. The second study used 12 ewes with twin pregnancies. Daily intravenous injections of either l-citrulline or l-alanine were administered for 39 d from d 42–45 to 81–84 of gestation. Ewes were limit-fed at 85% daily energy requirements during the injection period. A decrease (P < 0.0001) in body weight was observed in both treatment groups during this period. No treatment differences were observed in circulating pregnancy-specific protein B concentrations or placental blood flow during the treatment and post-treatment gestational period. No treatment differences were observed in lamb survival nor in lamb birth, weaning and slaughter weights. Treatment did not influence lamb carcass composition or organ weights. However, there was a tendency (P = 0.10) for an increase in antral follicle numbers in ovaries from ewe lambs derived from ewes treated with l-citrulline. In summary, a daily l-citrulline injection increased both circulating citrulline and arginine concentrations in ewes, but daily l-citrulline injections during mid-gestation did not produce any detectable changes in placental activity and blood flow, neonatal and postnatal lamb development, and lamb carcass composition at slaughter. In conclusion, no benefits in placental function and lamb development were observed after providing l-citrulline during mid-gestation in ewes exposed to a mild energy restriction, but there was an indication that follicle numbers in ewe lambs were positively influenced by l-citrulline treatment during fetal development.

Lying behaviour of housed and outdoor-managed pregnant sheep

Lying behaviour has been shown to be highly valuable in supporting the productivity and welfare of cattle. The aim of this experiment was to investigate the effect of biological and physical factors on the lying behaviour of sheep. Ninety-six Bluefaced Leicester x Welsh Mountain crossbred (Mule) ewes managed to lamb indoors, and 80 Welsh Mountain (WM) ewes managed to lamb at grass were used for the study. Acceleration values were collected for the two flocks from accelerometers fitted vertically to the outside of the rear right leg and set to record at 1-min intervals for at least 14 d prior to parturition. Ewes were simultaneously recorded using video equipment to identify lambing and to verify predictions of lying (total lying time, mean lying bout duration and total number of lying bouts) using data collected from 10 randomly selected ewes from the indoor flock on day -10 prior to lambing. Linear regression was used to evaluate predicted behaviours with video footage. Predictions of total lying time (R2 ≥ 0.99; P > 0.05 for slope = 1, intercept = 0), mean lying bout duration (R2 ≥ 0.99; P > 0.05 for slope = 1, intercept = 0) and total number of lying bouts (R2 ≥ 0.98; P > 0.05 for slope = 1, intercept = 0) were strongly associated with video footage (P < 0.001) demonstrating that a 1-min sampling interval provides reliable estimates of ewe lying behaviours. Measures of lying (mean daily lying time, mean lying bout duration and mean daily lying bouts) were calculated for all ewes using averages taken across days -10, -9 and -8 prior to lambing. Linear regression was used to test for effects of independent variables (pregnancy scan result (single- or twin-bearing), ewe age, ewe BCS, lambing ease, lamb sex and lamb birth weight) on each measure of lying. Significant associations (P < 0.05) were found between measures of lying and pregnancy scan result, ewe age, sex of singleton lambs and twin birth weight for housed, Mule ewes. Only ewe age and twin birth weight were significantly associated (P < 0.05) with measures of lying for WM ewes managed at grass. This information could help guide further research on sheep behaviour for management purposes (e.g., to optimise stocking densities and welfare for pregnant ewes). Further work should also consider evaluating measures of lying as proxies for imminent parturition.

Effect of early shearing during gestation on the performance of the progenie

Research has shown the interesting contributions of shearing during mid or late gestation on the performance of lambs from birth to weaning. However, there is no information on the effects of shearing in the first third of pregnancy, on the well-being and productivity of the offspring in adult life. The aim of this study was to investigate whether shearing during the first third of gestation, in a critical time window for the development of the placenta and the fetus, can influence the live weight at parturition, weaning and the survival of the lambs. Additionally, it was studied whether shearing in the first third of gestation is capable of programming metabolic and physiological modifications in the fetus that affect the growth, health and reproductive performance in the adult life of the offspring. Shearing in the first third of gestation significantly increased birth weight of single lambs (P = 0.004) and twins (P = 0.05). The higher weaning weight (P &lt; 0.0001) was related to the higher daily live weight gain (P ˂ 0.0001) in birth-weaning period. The extension of the gestation period (P &lt; 0.0001) explained only 56% and 87% (single and twins) of the increase in total live weight at lambing. Twin lambs from prepartum shorn ewes attempted (P = 0.004) and succeeded in suckling earlier (P = 0.0004) than control lambs. The greater vigor at lambing, together with the greater weight at weaning, may explain the higher (P = 0.04) survival rate. Early prepartum shearing did not affect live weight of ewe lambs from weaning to 18 months old. However, the gastrointestinal parasite egg counts per gram of fecal matter (P = 0.07), as well as the Famacha index (P = 0.02) were significantly lower than in controls. Prepartum shearing affected live weight of male lambs (P = 0.02), although there were no differences in the response to the parasitic challenge. Prepartum shearing did not affect any of the reproductive variables studied in ewes and male lambs. The results of this thesis show that shearing in the first third of gestation is a technique capable of affecting the productive performance of the offspring in the short and long term.

SEASONAL EFFECTS ON LAMB PRODUCTION UNDER TROPICAL CONDITIONS

Observations were made over a period of three years on a total of 336 West African Dwarf (WAD) ewes that were mated to four rams in rotation. Out of a total of 753 lambs obtained, 459 (61%) were produced in the wet season as compared to 294 (39%) produced in the dry season. More lambs were produced as a result of multiple birth (twins and triplets) in the wet than in the dry season. Consequently, the average birth weight of the wet season lambs (1.58kg) was lower than the average birth weight (1.66 kg) of the dry season lambs. Despite this initial disadvantage, the wet season lambs had a higher average weaning weight (9.11 kg) than the dry season lambs (7.83 kg). The effects of season on pre weaning lamb mortality was minimal while the effects of type of birth were quite apparent. Lowest pre-weaning lamb mortality values were recorded for single lambs, followed by twins and triplets, in ascending order. The data also showed that a slightly higher proportion of the male lambs reached weaning age than female lambs. This observation could be associated with reported inverse relationship between lamb birth weight and mortality found in literature.

INFLUENCE OF BIRTH WEIGHT, YEAR AND PARITY ON PREWEANING MORTALITY IN YANKASA SHEEP

The influence of lamb birth weights, year of&#x0D; birth, and parity on pre-weaning death were observed in Yankasa sheep over a period of 4 years (1989-1992) in Misau, Bauchi State, Nigeria. Of the 150 lambs observed, birth weight fell into 4 categories; upto 1.5; 1.6-2.0; 2.1-23 and 2.6 -3.0 Kg, with percentage deaths in each being 33, 34,16 and 0, respectively. The overall mean birth weight was 23±0.03, and overall percentage mortality was 18%. Significant correlation (p &lt; 0.05, r = 0.49) was observed between birth weights and deaths incidence. Significant year and parity differences existed in lamb birth weights (P.&lt; 0.05). 90% of the ewes lambing were in their 1st parity, while 6% and 4% respectively were in the 2nd and 3rd parities. Mean birth weights were heaviest for lambs with ewes in their 2nd parity 2.6 (0.46), followed by those in their 1st parity 23 (0.27) and those in their 3rd parity 2.2(0.27). Percentage mortality increased with parity, being 14,27 and 50 for 1st, 2nd and 3rd parities respectively. Chi-square analysis showed no significant differences between the ratio of ram to ewe lambs, though ram lambs were significantly heavier than ewe lambs. Low lamb birth weight was found to be a major cause of pre-weaning mortality in Yankasa sheep in Misau, Nigeria.

Effect of using supplementation mineral or organic selenium with vitamin E as antioxidants in the flushing diet on the fertility of ewes

In this study, 44 Afshari ewes were investigated that were 1–4 years old with a mean weight of 54–51 kg, with a physical score of approximately three in four experimental groups. Ewes were randomly assigned into four experimental groups including Group A Control (base diet recipient), Group B (Flushing), Group C (Flushing + Vitamin E Supplement + Organic Selenium), and Group D (Flushing + Vitamin E Supplement + Mineral Selenium). Blood sampling was carried out at different intervals namely beginning of the course, 24 h prior to CIDR, 24 h after CIDR (estrus), and 21 days after mating (at the time of embryonic implantation). Blood serum hormones (estrogen, progesterone, and insulin) were measured. The results of this study showed improvement in reproductive efficiency, especially the percentage of lambing, the fertility rate in Afshari breed. The use of organic selenium supplement with vitamin E and mineral selenium with vitamin E in the flushing diet before mating increased the reproductive performance of Afshari breed sheep by increasing the number of reproductive hormones (estrogen, progesterone, and insulin). C and A treatment had the highest and lowest lambs, respectively with 14 and 10 progenies. The highest birth weight of lambs was related to C treatment with an average of 4.49 kg. The use of two Flashing factors and vitamin E and organic selenium supplementation significantly increased the estrus and fertility, and significantly reduce the non-pregnant ewes by controlling oxidative conditions and increasing sex hormones.

The Effects of Energy Intake During late Pregnancy on Lamb Birth Weights and Lactation of Nigerian Dwarf Sheep

EIGHTEEN Nigerian Dwarf ewe lambs about eight months of age and weighing between 15 and 20 kg were divided into three groups, A, B, and C, and fed diets supplying 75, 100 and 125% of the ARC energy standards (1965) from the 15th week of pregnancy through lactation. Mean daily intakes during the last seven weeks of pregnancy were: dry matter 569, 748 and 826g: digestible organic matter 260, 496 and 593; and calculated metabolizable energy 0.99, 1.81 and 2.16 Mcal for groups A, B and respectively. The daily intakes during lactation were: 660, 748 and 857g of dry matter; 287, 593 and 690g of digestible organic matter and 1.05, 2.16 and 2.51 Mcal of calculated metabolizable energy for groups A, B and C respectively. Mean daily liveweight gains during the last seven weeks of pregnancy were 14.2, 99.0 and 90.0g and during lactation — 43.0, 7.9 and 10.4g for groups A, B and respectively, the differences being highly significant (P &lt;0.01). Mean birth weights of lambs were 1.18, 1.78 and 1.82kg for groups A, B and C respectively, the differences not being significant. Weight gains of lambs were highly significantly correlated with milk yield of their ewes. During a 10-week lactation period the differences in milk yields were highly significant between groups, with average daily yields of 312, 480 and 533g, for A, B and respectively. Peak yields were 481, 697 and 670 g for the respective groups between the second and third weeks of lactation. The mean values for milk composition were: fat, which remained relatively constant throughout lactation, 6.00, 6.36 and 6.40%; protein 4.82, 5.63 and 5.78%; lactose 4.15, 4.30 and 4.34%; total solids, which showed no definite trends during lactation, 15.98, 16.88 and 16.95%; and gross energy, which decreased with advancing lactation, 6.12, 6.18 and 6.38kcal/g for groups A, B and C respectively, the differences not being significant.

Determination of suitable oestrus synchronization protocols of ewes for lamb production in coastal areas of Bangladesh

The aim of this study was to produce lambs through hormonal synchronization of oestrous cycle in 1.5 to >3.5 year-old ewes. From coastal region of Bangladesh, a total of 45 ewes were selected and grouped as treatment (n=30) and control (n=15) group. Based on synchronization protocol, the treatment group was again divided into sub-group A (n=15) and B (n=15). In subgroup A, the ewes were injected intramuscularly with 2 ml of Ovuprost(R) (PGF2α) 9 days apart from first injection whereas in sub-group B, the ewes were injected intramuscularly with 2.5 ml Ovurelin(R) (GnRH) once. Though, sub-group A showed higher oestrus (93.33%) than control (60%), the differences were not significant (p>0.05). The pregnancy rate in treatment group (80%) was significantly (p 0.05) different. The ewes between 2.6 and 3.5 yr aged showed comparatively higher oestrus and pregnancy than 1.5 to 2.5 and >3.5 yr. The mean litter size and average birth weight of lambs were 1.13±0.41, 1.46±0.31, 1.27±0.34 and 1.17±0.04, 1.32±0.03, 1.29±0.04 kg in control, sub-groups A and B, respectively. It was concluded that the hormonal synchronization of oestrous cycle in ewes of coastal region of Bangladesh increased pregnancy rate.

EFFECT OF ADDITION PROTECTED FATTY ACIDS IN RUMINANT RATIONS ON PRODUCTIVE PERFORMANCE OF SUFFOLK X OSSIMI CROSSBRED EWES DURING DIFFERENT PRODUCTION STAGES

This study was conducted to evaluate the effect of dietary supplementation of protected fatty acids (FA) on nutrient digestibility, rumen parameters, some blood components, milk yield and its composition and lambs growth performance during the pre-weaning period (2 months old) of Suffolk x Ossimi ewes. A total of 36 pregnant ewes, weighing on the average 64.89±1.57 kg in their 2nd – 4th parities and aged 2.5 – 4.5 years were divided into three similar groups according to their body weight (12 ewes each) using a complete randomized block design .The feeding trial started 60 days before lambing (late pregnancy period) and continued 60 days after lambing (suckling period). The experimental rations were offered into animals with the rate of 0, 4 and 6% calcium-soap as protected fatty acids (based on DM intake). Body weight, total gain and daily gain of the new born lambs were recorded during the preweaning period (suckling period). The basal rations composed of 60% concentrate feed mixture (CFM) and 40% roughage (berseem 30% + rice straw 10%, RS).Three digestibility trials were carried out using nine Suffolk x Ossimi crossbred rams with average 62 kg BW and aged 2-2.5 years to determine the digestibility and feeding values of the experimental rations. Data showed that significant higher digestibility at (P <0.05) of OM, CP, CF, EE and NFE for fat supplemented groups than those of control one. Rumen parameters (pH, total VFAs and ammonia-N concentration) were higher in supplemented groups than those of the control one. Values of concentrations of blood plasma total protein and its fractions, glucose, total cholesterol, triglycerides and total lipids of experimental ewes were higher in for supplemented groups than that of control one in the two stages of the whole production cycle. Supplemented fat treatments (group) led to significant increases in birth, weaning weights and total gain of lambs, and the highest values were occurred with FA6. Milk yield was higher significantly in supplemented groups than that of control one as well as its composition (fat, total solids and protein, %) were followed the same trend of milk yield among treatments. Generally, it could be concluded that the supplementation of calcium salt of fatty acids at different levels (FA4 or FA6) for rations of Suffolk x Ossimi crossbred ewes improved digestibility, feeding values, increased lambs birth weight and milk yield and its composition beside better feed efficiency, with superiority of 6% level (FA6).

Feeding Tall Fescue Seed Reduces Ewe Milk Production, Lamb Birth Weight and Pre-Weaning Growth Rate.

Simple SummaryThis study was conducted to examine how ergovaline/ergovalinine ingestion during pregnancy in ewes with different DRD2 genotypes altered ewe and lamb performance. Feeding ergovaline/ergovalinine in last trimester reduced lamb birth weight; however, milk production was lower for all ewes fed ergovaline/ergovalinine. Lambs born to dams fed ergovaline/ergovalinine had slower growth rates and lower weaning weights. These results demonstrate that ingestion of ergot alkaloids during pregnancy can negatively influence lactation, growth of offspring and birth and weaning weights. Recommendations would include strategies to mitigate mycotoxin exposure in pregnant ewes to improve production.Endophyte-infected tall fescue (E+) produces ergovaline and ergovalinine, which are mycotoxins that act as dopamine agonists to suppress prolactin and induce vasoconstriction. The experiment was designed as a 3 × 2 × 2 factorial with DRD2 genotype (AA, AG, GG), fescue seed (endophyte-free, E− or endophyte-infected, E+), stage of gestation (MID, d (day) 35–85; LATE, d 86–parturition) and all interactions in the model. Pregnant Suffolk ewes (n = 60) were stratified by genotype and fed E+ or E− seed in a total mixed ration according to treatment assignment. Serum prolactin concentrations were lower (p < 0.05) in ewes fed E+ seed but did not differ by maternal DRD2 genotype or two-way interaction. Lamb birth weight was lower (p < 0.05) in ewes fed E+ seed in last trimester. Pre-weaning growth rate, milk production and total weaning weight was reduced (p < 0.05) in ewes fed E+ fescue seed during MID and LATE gestation. Ingestion of ergovaline/ergovalinine in last trimester reduces lamb birth weight; however, lamb growth rate, milk production and total weaning weight are reduced in all ewes fed E+ during mid and last trimester.