Lamb Birth Weight Research Articles

Community-based sheep breeding programs generated substantial genetic gains and socioeconomic benefits

Community-based breeding programs (CBBPs) for small ruminants have been suggested as alternatives to centralised, government-controlled breeding schemes which have been implemented in many developing countries. An innovative methodological framework on how to design, implement and sustain CBBPs was tested in three sites in Ethiopia: Bonga, Horro and Menz. In these CBBPs, the main selection trait identified through participatory approaches was 6-month weight in all three sites. In Horro and Bonga, where resources such as feed and water permitted larger litter sizes, twinning rate was included. Ten-year (2009 to 2018) performance data from the breeding programs were analysed using Average Information Restricted Maximum Likelihood method (AI-REML). Additionally, the socioeconomic impact of CBBPs was assessed. Results indicated that 6-month weight increased over the years in all breeds. In Bonga, the average increase was 0.21 ± 0.018 kg/year, followed by 0.18 ± 0.007 and 0.11 ± 0.003 kg/year in Horro and Menz, respectively. This was quite substantial in an on-farm situation. The birth weight of lambs did not improve over the years in Bonga and Horro sheep but significant increases occurred in Menz. Considering that there was no direct selection on birth weight in the community flock, the increased weights observed in Menz could be due to correlated responses, but this was not the case in Bonga and Horro. The genetic trend for prolificacy over the years in both Bonga and Horro flocks was positive and significant (P < 0.01). This increase in litter size, combined with the increased 6-month body weight, increased income by 20% and farm-level meat consumption from slaughter of one sheep per year to three. The results show that CBBPs are technically feasible, result in measurable genetic gains in performance traits and impact the livelihoods of farmers.

Shearing during late pregnancy increases size at birth but does not alter placental endocrine responses in sheep

Shearing during the latter half of pregnancy is a common practice to improve flock health and productivity. Previous studies have demonstrated that shearing pregnant ewes at mid or late pregnancy is associated with an increase in lamb birth weight. In the present study, we used singleton Polypay × Dorset pregnant sheep, to investigate the potential roles of placental function and changes in maternal metabolism in underlying this increased birth weight response. Two groups were randomly established and blocked at enrollment by animal BW, body condition score and subcutaneous adipose tissue depth. The groups were shorn (SH; n = 18) or not (C; n = 20) at gestational day (GD) 107 ± 1 (mean ± SEM). Weekly maternal plasma samples were collected between shearing and birth, but only six samples were assayed for progesterone, pregnancy-associated glycoproteins (PAG1), glucose and non-esterified fatty acids (NEFAs). At birth, sex, birth weight, and newborn body mass index (BMI) were recorded. Maternal BW during mid- to late-pregnancy was similar between groups. Shearing resulted in increased lamb birth weight and BMI (P < 0.05) regardless of fetal sex but did not affect the maternal concentration of PAG1 or progesterone from GDs 100 to 142. After shearing (GD100) and up to lambing, shorn females had higher circulating glucose concentrations (P < 0.05), but not NEFA, compared to the control group. Maternal circulating PAG1, progesterone, glucose or NEFA concentration across pregnancy did not differ according to lamb sex. Across pregnancy, birth weight was positively associated with PAG1 (P < 0.001), but not with progesterone concentrations. In conclusion, weight and BMI at birth were higher in both sexes upon shearing in singleton pregnancies. Despite PAG1 being associated with birth weight, late-pregnancy shearing did not alter the placental endocrine response. Whether other placental factors are altered upon shearing and may influence the increase in birth weight and BMI remain to be investigated.

Effect of Nutrition During the Last Stages of Pregnancy on Lamb Birth Weight and Growth Performance in Balkhi Ewes

Effect of Nutrition During the Last Stages of Pregnancy on Lamb Birth Weight and Growth Performance in Balkhi Ewes

Effects of protein supplements on fertility and assessment of the fertility genes (GDF9 and BMP15) in indigenous sheep of Bangladesh

ABSTRACT The study was conducted to investigate the effect of different levels of protein supplements on fertility and assess the fertility gene (BMP15 and GDP9) in sheep of Bangladesh. Thirty six ewes fed two protein level (Treatment 1, T1 and treatment 2, T2) and no protein supplement ration (control, T0). Polymerase chain reactions (PCR) were performed from blood cell DNA following standard protocols. PCR products were sequenced using Sanger sequencing and MEGA6 software were used for molecular analysis. The conception rate of ewes was significantly higher (P < 0.05) in the treated group than the control. Gestation period and lambing interval were significantly higher (worse) in control (154.00 ± 0.57 and 186.00 ± 1.24 days) than treated groups. Birth weight of lamb ranged from 1.07 to 1.65 kg and higher birth weight was found in T2 than other groups. Sequence alignment of BMP15 and GDF9 gene in indigenous sheep showed 100% homology with other sheep breed. As no mutation was observed and apparently these genes have no effect on ewe fertility. However, nutritional supplements had a positive impact on reproductive performance. The phylogenetic inferences have close relations of Bangladeshi sheep with other breed elsewhere.

167 Evaluation of an out-of-season breeding system for organic lamb production in missouri

Abstract Organic production is one of the fastest growing food and agriculture industry. The seasonality of lamb production affects lamb markets and prices, whereas, an out-of-season breeding and organic fall lamb production scheme may enhance product availability and competiveness. Six rams and 100 Katahdin ewes were selected for an out-of-season breeding during April and May of 2017 and 2018, for two production years. Ewes were synchronized for estrus using CIDR® device (EaziBreed™) (12 d) before breeding and fed ‘flushing’ feed for four weeks. Ewes were bred in mixed sire groups for two estrus cycles (35 d). Animals were rotationally grazed and maintained good body condition score (3.0) throughout the seasons at certified organic farm in Missouri. Mean live weight measured monthly from breeding to lambing were 57.8, 60.1, 62.1, 64.7, and 59.3 kg. Eighty nine ewes lambed in fall 2017 giving birth to 121 lambs (136% lambing rate) and eighty eight ewes lambed in 2018 giving birth to 126 lambs (143% lambing rate). Ninety seven percent of weaned lambs were maintained as an organic production status for marketing. Lamb birth weight, average daily gain weight, weaning weight, and 30 d post weaning weight, post weaning average daily gain weight were recorded for 2017 born lambs as 3.74±0.03 kg, 21.00±0.24 kg, 24.78±0.28 kg, 176±2 g/d respectively. Organic weaner lambs were sold for 5 to 15% higher price values (P &amp;lt; 0.05) per unit than non-organic peer groups at a local livestock auction sale.

PSI-20 The effect of ewe gastrointestinal nematode burden during the periparturient period on lamb growth

Abstract Research evaluating the effects of ewe gastrointestinal nematode infection (GNI) during the periparturient period (PPR) on offspring growth is limited. We hypothesized ewes with a greater parasite burden during the PPR will negatively impact birth and weaning weight. Packed cell volume (PCV) was measured in ewes (2018, n = 11) at 3 weeks pre-partum (-3), birth, 3 (+3) and 6 (+6) wks postpartum. Lamb birth weight, weaning weight (WW), and ADG (birth - 8 weeks) were collected. Ewes in the upper 50% (n = 5–6) and lower 50% (n = 5–6) for PCV were classified as either HIGH and LOW at each time period. Data were analyzed in SAS using proc mixed (significance P ≤ 0.05). PCVs for LOW and HIGH ewes were (mean ± SEM) 27% ± 0.2% vs 30% ± 0.8% at -3, 28% ± 0.3% vs 32% ± 0.4% at birth, 24% ± 0.4% vs 29% ± 0.6% at +3, and 25% ± 0.2% vs 30% ± 1.0% at +6 respectively. Post-partum, lambs reared by LOW ewes exhibited reduced ADG (0.69 ± 0.03 kg/d vs 0.81 ± 0.03 kg/d; P = 0.02) and WW (29.34 kg ± 1.41 kg vs 33.64 kg ± 1.47 kg; P = 0.04) compared to lambs reared by HIGH ewes. Lambs reared by LOW ewes at +3 exhibited reduced ADG versus lambs reared by HIGH ewes (0.69 ± 0.034 kg/d vs. 0.81 ± 0.034 kg/d; P = 0.02). No effect of maternal PCV on birth weight or WW, at -3, birth, or +6 was observed on offspring birth weight, WW, or ADG (P ≥ 0.13). In conclusion, the effects of PPR GNI appear to be postnatal.

164 The effect of grass silage compared to whole crop wheat silage on colostrum yield, lamb birth weight and ewe performance during late gestation

Abstract Number of lambs born is a key factor influencing profitability of seasonal sheep meat production systems and a key driver of nutrient requirements. Energy and nutrient requirements to support foetal development, mammogenesis and lactogensis increase in the final eight weeks of ovine gestation. A 3 × 2 factorial design experiment involving 90 twin bearing ewes was conducted during the final eight weeks of pregnancy with ewes offered 100% of predicted metabolisable energy (ME) requirements. Three prolific breed types (Mule (Bluefaced Leicester X Blackface mountain), Belclare X and Lleyn X) were offered one of two silage types (grass (GS) or whole crop wheat (WCW)) resulting in six treatments (n = 15). Where silage intake was insufficient to meet 100% of ME requirements, concentrates were offered to reach 100% of ME allocation per ewe per day. Colostrum yield at one, ten and eighteen hours, combined litter weight (CLW), maternal body weight and body condition score (BCS) change during the final eight weeks of gestation were recorded. The data were analysed using repeated measures and glimmix in SAS (Version 9.4). Ewes offered grass silage produced lambs with a higher CLW (P = 0.03). There was an interaction between breed type and silage type with Mule ewes offered WCW producing a lower CLW than Mule ewes offered GS (P = 0.004), with no difference for Belclare or Lleyn ewes (P &amp;gt; 0.05). Within silage type Mule ewes offered GS had a higher CLW than Belclare ewes (P &amp;lt; 0.05) while within WCW Belclare ewes had a higher CLW than Lleyn ewes (P &amp;lt; 0.05). Other variables did not differ with treatment. In conclusion, a breed specific response was recorded in this study whereby Mule ewes produced a lower CLW when offered WCW compared to GS silage, though no differences were observed in the other breed types studied.

The Effect of Some Environmental Factors on the Birth Weight in Anatolian Merino Sheep

In this study, the data of 1510 lambs born in a private sheep farm in Eregli district of Konya in 2018-2019 were evaluated. Birth type, birth times, birth weight and sex of lambs were investigated in this study. 892 of the lambs were born in 2018 and 618 of them were born in 2019. A total of 1510 lambs were born, 699 of them were born in singles, 761 in twins and 50 in triplets. The total number of sheep is 1096. 681 of the lambs were male and 829 were female. Of the environmental factors affecting birth weight, while the effect of the year was statistically insignificant (p &lt;0.05), the effect of season, type of birth and sex was significant (p &lt;0.01). Lambs born in spring have more live weight than those born in other seasons. The live weight of male lambs is higher than that of females, whereas the weight of single born lambs is higher than that of twins and triplets.

Development of Agrinak Compass Sheep in the Application of Seedlings from Superior Science and Technology

The appearance of sheep Compass Agrinak (CA) with pastura care management such as the habits of farmers in Indramayu district shows that CA sheep can adapt well. The research method used in the research is social and technical approaches. One of the indicator can be seen from the birth weight of lambs from cross-breeding between local ewe and CA buck. Birth weight of lambs from crosses is relatively higher than local lambs, which is 3.08 vs 2.5 kg for females and 3.50 vs 3.04 for males. Some problems that require more careful observation where CA sheep die because of “consumed” plastic that may still have left in them as food leftovers consumed by humans wrapped in plastic bags, so that when eating the leaves “eaten” also the plastic wrap that blocks the system digestion and breathing which eventually die. Technology guidance on the preparation of sheep feed from rice (straw) by-products has been carried out at the Bogor experimental station as well as making good and true block minerals and sheep cultivation.

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.

Refeeding ewe’s ad libitum after energy restriction during mid-pregnancy does not affect lamb feed conversion ratio, animal performance and meat quality

The aim of the study was to evaluate maternal energy restriction in ewes from day 48 to 106 of gestation on pre- and post-weaning lambs`’ performance, carcass and meat quality when their dams were fed ad libitum after the restriction period. Ewes bearing single or twin lambs were assigned to two dietary treatments from day 48 to day 106 of gestation: restricted (R; n = 60) at 60% of their metabolizable energy (ME) requirements, or non-restricted (NR; n = 54) at 100% of their ME requirements. After the restriction period ewes grazed all together ad libitum until weaning. Subsequently, male lambs were placed in a feedlot until slaughter. Ewes body weight was recorded during nutritional treatment application and at weaning. Litter size and lamb sex were recorded, and feed intake and body weight were measured from birth until slaughter. After slaughter, carcass weight and yield, subcutaneous tissue depth (GR site), carcass (CL) and leg length (LL), frenched rack (FR) and leg weights were determined. After 5 days of meat aging, color parameters and Warner-Bratzler shear force were determined on longissimus lumborum muscle. Non-restricted ewes weighed 7.5 kg more than R ewes (P < 0.05) at the end of the restriction period. Lamb birth weight (BW) was no affected (P > 0.05) by dams’ treatment although male and single lambs had a greater (P < 0.05) BW than females and twins, respectively. No significant differences (P > 0.05) were detected on the weaning weight between ewes’ feeding treatments or lamb sex. Estimated average milk intake by lambs was not affected (P > 0.05) by dams’ treatments and litter size. Lambs born to R or NR ewes did not differ (P > 0.05) in feed conversion ratio (FCR) of milk, while twins were more efficient (P < 0.05) than single-born. Male lambs from R and NR ewes did not differ (P > 0.05) in weaning and final weight, feed intake and FCR during the fattening phase. Slaughter and hot carcass weight, carcass yield (CYd), GR, CL and LL were not affected (P > 0.05) by treatment and litter size. Brightness of meat (L* value) was greater (P < 0.05) in lambs from R ewes than NR. Ewes restricted at 60% of their ME requirements in mid-gestation seems to have the capacity to compensate any detrimental effects on lamb growth and development if adequate refeeding conditions are provided in late gestation and throughout lactation.

Niğde İlinde Yetiştirilen Akkaraman Irkı Koyunların Bazı Döl Verim Özellikleri ve Kuzuların Büyüme Performansı

Bu çalışmada, yarı ekstansif koşullarda yetiştirilen Akkaraman koyunlarının bazı döl verim özellikleri ile kuzuların büyüme performansları araştırılmıştır. Araştırmanın hayvan materyalini, Niğde merkez ilçesine bağlı 34 işletmede bulunan 300 baş koç, 6000 baş Akkaraman koyunu ile onların kuzuları oluşturmuştur. Araştırma 2012-2016 yılları arasında 5 yıl sürdürülmüş ve çalışma süresince 30162 baş kuzu doğum ağırlığı, 29517 baş kuzunun 90. gün canlı ağırlığı ve 30000 baş Akkaraman koyununun bazı döl verim parametreleri saptanmıştır. Akkaraman koyunlarında doğum oranı ortalama %90,1, ikiz doğum oranı %20,8, bir doğuma düşen kuzu sayısı 1,12 olarak saptanmıştır. Akkaraman ırkı kuzuların doğum ağırlığının ortalaması 4,23 kg ve 90. gün canlı ağırlık ortalaması da 23,05 kg olarak belirlenmiştir. Kuzuların doğum ağırlıkları ve 90. gün canlı ağırlıkları üzerine yıl, doğum tipi ve cinsiyetin etkisi önemli bulunmuştur. Sonuç olarak, halk elinde yarı ekstansif koşullarda yetiştirilen Akkaraman ırkı koyunların döl verimi ve kuzuların büyüme özelliklerinin iyileştirilebileceği ve bunun gibi ıslah projelerinin uygulanması ile koyunculuk işletmelerin ekonomik durumlarının iyileştirilebileceği kanaatine varılmıştır.

Risk factors and genetic analysis of pre-weaning mortality in Barki lambs

Pre-weaning mortality (PM) of lambs is a worldwide economically trait of interest. It has a negative impact on the profitability of sheep farms. However, little is known about the genetic contribution of PM in Egypt and worldwide. In this study, a total of 21,280 records of 5317 Barki lambs descended from 153 rams and 1887 ewes were included. Based on the time of death, 4 binary traits were recorded; D0–3 was animals that were dead immediately or within 72 h after delivery, D4–60, D61–90, and D0–90 were lambs that were dead during 4–60 days, 61–90 days after birth and the full period (0–90 days), respectively. The average rate of mortalities for the corresponding traits was 4.6%, 5.4%, 4.3%, 2.2%, and 16.3%, respectively. A logistic regression model with a logit function implemented in R was used to assess the impact of the non-genetic factors on PM in Barki lambs. Bayesian threshold model and Gibbs sampling were used to investigate the genetic parameters and (co)variance components of the studied traits. Results showed that the PM traits were significantly (P < 0.05) influenced by damage, type of birth and birth weight of lamb. Direct heritabilities for PM traits ranged from 0.011 ± 0.01 to 0.02 ± 0.01. Maternal genetic effects for PM traits ranged from 0.13 ± 0.02 to 0.23 ± 0.01. Considerably, maternal effects had a large influence on variance estimates in case of PM trait, but these effects have declined as the lamb age increased. Permanent environmental effects for PM traits ranged from 0.06 ± 0.02 to 0.11 ± 0.02. The genetic correlations between the pairs of studied traits were positively moderate to high and ranged from 0.72 ± 0.07 to 0.95 ± 0.03, which suggested that different genes are contributed to lamb mortality at different ages. Notably, lamb mortality trait was found to be heritable and could be used as important criteria in breeding programs and genetic improvement strategies in Barki sheep. Additionally, improving management practices could also reduce lamb mortality. Results of this study may help animal breeders to reduce lamb mortality in Barki sheep.

An investigation into the factors associated with ewe colostrum production

The majority of lamb mortality which occurs during the first 24 h post-partum is preventable through providing the lamb with sufficient quantities of high quality colostrum during this time. Data from seven late gestation nutrition experiments carried out at this institute between 2002 and 2014 were collated into a single data set comprising of 415 twin bearing ewes. Analysis was carried out to investigate the key drivers of ewe colostrum production excluding nutrient intake, namely body reserve mobilisation, ewe breed type, ewe age, gestation length and lamb birth weight. The volume of colostrum produced at 1 and 18 h post-partum was significantly lower than the volume recorded at 10 h post-partum (P = 0.01). Multivariate regression analysis indicated that colostrum volume during the first 18 h post-partum was influenced by lamb birth weight (P = 0.01), ewe age (P = 0.01), breed type (P = 0. 01) and gestation length (P = 0.06). Live weight change (P = 0.05) also had a significant influence on the volume of colostrum produced but BCS change did not affect colostrum production (P = 0.25). Further multivariate regression analysis indicated that IgG yield was influenced ewe breed type (P = 0.01), lamb birth weight (P = 0.02), gestation length (P = 0.05) and BCS change (P = 0.04). Live weight change (P = 0.12) and ewe age (P = 0.62) did not influence the quantity of IgG produced. Leicester ewes produced less colostrum per kg lamb birth weight at 1 h post-partum compared to all other ewe breed types (P = 0.01) and less than Suffolk ewes at 10 h post-partum (P = 0.01). The result of this analysis shows the key factors excluding ewe nutrition that drive colostrum production. Ewe breed type in particular appears to play an important role in the ability of the ewe to produce sufficient quantities of adequate quality colostrum. In conclusion the result of this analysis highlights the important factors associated with ewe colostrum volume and IgG yield excluding nutrition. In particular the overall structure of the flock such as breed type and ewe age is important when considering the ability of the flock to meet colostrum demands and hence reduce lamb mortality.

Competition for nutrients in pregnant adolescents: consequences for maternal, conceptus and offspring endocrine systems.

The competition for nutrients that arises when pregnancy coincides with continuing or incomplete growth in young adolescent girls increases the risk of preterm delivery and low birthweight with negative after-effects for mother and child extending beyond the perinatal period. Sheep paradigms involving nutritional management of weight and adiposity in young, biologically immature adolescents have allowed the consequences of differential maternal growth status to be explored. Although nutrient reserves at conception play a modest role, it is the dietary manipulation of the maternal growth trajectory thereafter which has the most negative impact on pregnancy outcome. Overnourishing adolescents to promote rapid maternal growth is particularly detrimental as placental growth, uteroplacental blood flows and fetal nutrient delivery are perturbed leading to a high incidence of fetal growth restriction and premature delivery of low birthweight lambs, whereas in undernourished adolescents further maternal growth is prevented, and depletion of the maternal body results in a small reduction in birthweight independent of placental size. Maternal and placental endocrine systems are differentially altered in both paradigms with downstream effects on fetal endocrine systems, organ development and body composition. Approaches to reverse these effects have been explored, predominantly targeting placental growth or function. After birth, growth-restricted offspring born to overnourished adolescents and fed to appetite have an altered metabolic phenotype which persists into adulthood, whereas offspring of undernourished adolescents are largely unaffected. This body of work using ovine paradigms has public health implications for nutritional advice offered to young adolescents before and during pregnancy, and their offspring thereafter.

Effects of Streptococcus dysgalactiae polyarthritis on lamb growth and mortality and risk factors for disease

This study describes an outbreak of infectious polyarthritis due to Streptococcus dysgalactiae in a New Zealand sheep flock, evaluates the effects on lamb growth rates and mortality and investigates risk factors for disease development. Data from 76 affected lambs and up to 2223 unaffected lambs were used. On average, affected lambs had a 54.4 g/day reduction in growth rate from birth to weaning; at an average weaning age of 82 days this amounted to a 4.5 kg reduction in weaning weight. The pre-weaning mortality of affected lambs was 10% higher than for unaffected lambs. The only factors that were significantly associated with development of the disease were time of birth and birth area (groups of paddocks with similar physical characteristics) whereas there was no association with lamb birthweight, gender, litter size or vigour score or with dam age, body condition score or maternal behaviour score.

Organic and inorganic selenium supplementation on the productive and reproductive performance of hair ewes

The objective of this study was to evaluate the effect of supplementation with organic and inorganic selenium on the productive and reproductive performance of ewes and their offspring. Selenium (Se) is an essential mineral for sheep, studies have found its intestinal absorption and biodisponibility in the animal is greater when it comes from an organic source. A total of 18 multiparous and 22 nulliparous ewes Pelibuey breed were used in this study, averaging 54.8 ± 9.4 kg and 39.7 ± 5.6 kg of body weight (BW). The experimental units were blocked by the number of parturitions (none or more than one). Then randomly assigned to one treatment: basal diet +1.2 ppm of organic Se (OSe, Sel- Plex®) or basal diet +1.2 ppm inorganic Se (ISe). Using the linear model PROC MIXED, BW changes were measured in ewes and average daily gain (ADG) in offspring. Fisher’s test, chi-squared test and t test were used for analyzing reproductive rates and production efficiency. No differences (P &gt; 0.05) were found for BW changes, productive efficiency, and pregnancy rate between treatments. Prolificacy was higher (P &lt; 0.05) for primiparous ewes in the OSe group vs the ISe group (66.7 vs 18.2 %). No differences (P &gt; 0.05) were found for birth weights of lambs. The ADG was higher (P &lt; 0.05) for the offspring of ISe vs OSe ewes. This indicates that the OSe supplementation improves reproductive parameters, but not the productive such as ADG. DOI: https://doi.org/10.54167/tch.v13i1.303

Relationships of body surface thermography with core temperature, birth weight and climatic variables in neonatal lambs born during early spring in an arid region.

The main cause of death in newborn lambs is hypothermia, so is necessary to identify the factors affecting variations in body surface temperatures of sheep neonates because approximately 60% of their body heat losses occur through the skin. This study aimed to establish relationships among body surface thermography from different regions with rectal temperature (RT), birth weight (BW) and climatic variables in hair breed newborn lambs during early spring in an arid region. Data of body surface temperatures measured by infrared thermography (entire head, eye, muzzle, ear, entire body, shoulder, rump, loin, right flank, belly and leg), RT and BW were collected at 0, 12 and 24 h post-lambing in 85 lambs born in early spring. Relative humidity [RH], temperature [Te] and temperature-humidity index [THI] were also recorded. RT was not correlated with surface temperatures at 0 and 24 h, but it was at 12 h with all of them (0.36 ≤ r ≤ 0.44). BW and some surface temperatures were negatively correlated at 0 and 24 h (-0.24 ≤ r ≤ -0.30), but positively at 12 h (0.25 ≤ r ≤ 0.27). All surface temperatures were positively correlated (0.51 ≤ r ≤ 0.85) with Te and THI in the three sampling times. Principal component (PC) analysis showed that PC1 explained the majority of the variance (71-72%), followed by PC2 (8-9%) at 0, 12 and 24 h. Body surface temperatures increased as Te and THI also increased, but decreased with the increase in HR. In conclusion, under early spring environment (predominantly cold), the variations in body surface temperatures of hair sheep neonates were more closely related to climatic variables than to RT and BW. Thermography proved to be an effective tool to determine body heat loss by radiation in skin of neonate lambs.

EFFECT OF FEEDING DIFFERENT CONCENTRATE ROUGHAGE RATIO ON GROWTH, REPRODUCTIVE PERFORMANCE AND BEHAVIOR OF SHEEP

The goal of this study was to examine the influence of feeding different concentrate roughage ratios on growth, reproductive parameters and behavior of sheep. The study design involved the use of a 30 sexually mature ewes assigned to three groups consisting of three ratios of concentrate (C) to roughage (R), Group1. 80%C: 20%R, Group2. 70%C: 30%R and Group3. 60%C: 40%R. The variables of the studies were live weight changes and Body condition score (BCS) of ewes during pregnancy and postpartum till weaning and behavior of ewes in addition to the birth weight and average daily gain of neonatal lambs and subsequent changes till weaning. The conception rate of ewes and their overall reproductive performance are under investigation. The results reveled that, different ratios of concentrate and roughage feeding had no significant effect on body weight, BCS and average dry matter intake of ewes during pregnancy and postpartum till weaning. Lambs birth weight and subsequent weights till weaning and average daily gain were significantly (P≤0.05) increased by feeding on ration contain 80%C: 20% R, followed by those feeding on 70% C: 30% R and lowest in those feeding on 60% C: 40%R. Rumination was significantly increased in Group3 lambs than other groups. Higher concentrate ratios had positive effect on reproductive performance of ewes and body weight, daily body weight gain and neonatal behavior of lambs till weaning.Key words: concentrate; roughage; ewe; lamb; growth performance; behavior

Consequences of intra-uterine growth retardation for postnatal growth, metabolism and pathophysiology

Intra-uterine growth retardation (IUGR), caused by maternal undernutrition or placental insufficiency, is usually associated with disproportionately large reductions in the growth of some fetal organs and tissues (thymus, liver, spleen, thyroid) and impaired cellular development of other tissues (small intestine, secondary wool follicles, skeletal muscle). Growth of other tissues, most notably brain, is relatively unimpaired. In our restudy of postnatal consequences of IUGR in the offspring of prolific ewes, growth-retarded newborn lambs tended to be hypoglycaemic and showed sluggish postnatal engagement of the growth hormone (GH)-insulin-like growth factor (IGF) system. When artificially reared in an optimum environment, low birth weight lambs grew at rates similar to those of normal lambs. However, low birth weight lambs were fatter at any given weight, apparently related to their high energy intakes, especially soon after birth, had low maintenance energy requirements, and limited capacity for bone and muscle growth. These growth characteristics were accompanied by higher plasma concentrations of GH and leptin, and lower concentrations of insulin-like growth factor I (IGF-I) during the first 2 weeks of postnatal life, and higher concentrations of insulin during subsequent growth up to 20 kg body weight. Emerging evidence indicates that in sheep, as in rodents, fetal programming of postnatal cardiovascular and metabolic dysfunctions is associated with IUGR and may be mediated partly by overexposure of the fetus to cortisol. Similar postnatal responses can be elicited by maternal undernutrition or cortisol treatment in early to mid-pregnancy without changing the growth of the fetus or placenta.