Adaptation and performance evaluation of Perendale, Dorper, and Suffolksheep in Bangladesh

Sheep production is affected by genetic and non-genetic factors. A knowledge of these factors is essential for efficient management and for the accurate estimation of breeding values. The objective of this study was to establish the non-genetic factors which affect birth weight and weaning weight in Dorper, Mutton Merino and indigenous Sabi sheep breeds. A total of 2,625 birth and weaning weight records from Grasslands Research Station collected from 1991 through 1993, were used. The records were collected from indigenous Sabi (939), Dorper (807) and Mutton Merino (898) sheep. A mixed classification model containing the fixed effects of year, birth status and sex was used for identification of non-genetic factors. Sire within breed was included as a random effect. Two factor interactions and three factor interactions were important in indigenous Sabi, Mutton Merino and Dorper sheep. The mean birth weights were 4.37±0.04 kg, 4.62±0.04 kg and 3.29±0.04 kg for Mutton Merino, Dorper and Sabi sheep, respectively. Sire had significant effects (p<0.05) on birth weight in Mutton Merino and indigenous Sabi sheep. Year of lambing had significant effects (p<0.05) on birth weight in indigenous Sabi, Mutton Merino and Dorper sheep. The effect of birth status was non significant in Dorper and Mutton Merino sheep while effect of birth status was significant on birth weight in indigenous Sabi sheep. In Indigenous Sabi sheep lambs born as singles (3.30±0.05 kg) were 0.23 kg heavier than twins (3.07±0.05 kg), in Mutton Merino lambs born as singles (3.99±0.08 kg) were 0.07 kg heavier than twins (3.92±0.08 kg) and in Dorper lambs born as singles (4.41±0.04 kg) were 0.02 kg heavier than twins (4.39±0.04 kg). On average males were heavier than females (p<0.05) weighing (3.32±0.04 kg vs. 3.05±0.07 kg) in indigenous Sabi, 4.73±0.03 kg vs. 4.08±0.05 in Dorper and 4.26±0.07 kg vs. 3.66±0.09 kg in Mutton Merino sheep. Two way factor interactions of sire*year, year*sex and sex*birth status had significant effects (p<0.05) on birth weight in indigenous Sabi, Mutton Merino and Dorper sheep while the effect of year*birth status was non significant on birth weight in Indigenous Sabi sheep. The three way factor interaction of year*sex*birth status had a significant effect (p<0.01) on birth weight in indigenous Sabi and Mutton Merino. Tupping weight fitted as a covariate had significant effects (p<0.001) on birth weight in indigenous Sabi, Mutton Merino and Dorper sheep. The mean weaning weights were 17.94±0.31 kg, 18.19±0.28 kg and 14.39±0.28 kg for Mutton Merino, Dorper and Indigenous Sabi sheep, respectively. Effects of sire and sire*year were non significant on weaning weight in Dorper and Mutton Merino while year, sex and sex*year interaction had significant effects (p<0.001) on weaning weight. On average males were heavier than females (p<0.001) at weaning. The respective weaning weights were 18.05±0.46 kg, 18.68±0.19 kg, 14.14±0.15 kg for males and 16.64±0.60 kg, 16.41±0.31 kg, 12.64±0.32 kg for females in Mutton Merino, Dorper and Indigenous Sabi sheep. Lambs born as singles were significantly heavier at weaning than twins, 0.05 kg, 0.06 kg and 0.78 kg for Mutton Merino, Dorper and Indigenous Sabi sheep, respectively. Effect of tupping weight was highly significant on weaning weight. The three way factor interaction year*sex*birth status had a significant effect (p<0.01) on weaning weight. Correction for environmental effects is necessary to increase accuracy of direct selection for birth weight and weaning weight. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 2 : 151-157)

The productive and reproductive performance of, as well as income generated by Afrino, Dorper and Merino sheep at two localities in the False Upper Karoo region were evaluated. A total of 1242 ewe reproductive records was available, while data of respectively 772 and 405 lambs were analysed for the growth traits and slaughter traits. Percentage of lambs weaned per ewe in the flock was 132.0%, 100.0% and 93.7% for Afrino, Dorper and Merino ewes at Grootvlei, respectively. Corresponding values for Twistkraal were 153.3%, 114.7% and 96.4%, respectively. Body weights of 52.3 ± 1.4 kg, 56.6 ± 1.4 kg and 43.4 ± 1.4 kg were recorded for Afrino, Dorper and Merino ewes, respectively. Merino ewes produced on average 1.3 kg more clean wool, of a 0.6 μm stronger diameter than Afrino ewes. At each locality Dorper lambs were the heaviest at weaning, followed by Afrino and then by the Merino lambs. Dorper lambs were slaughtered earlier than Afrino lambs, with Merino lambs taking the longest interval to reach slaughter weight. A definite seasonal effect was also evident, where the autumn-born lambs reached slaughter weight earlier than spring-born lambs in all breeds. With the current wool and mutton prices, Afrino sheep had the highest gross income per ewe, followed by Merino and Dorper ewes respectively. However, Merino sheep had the highest gross income per hectare at both localities, followed by Afrino and then Dorper sheep. The combination of low ewe body weights, high wool production and a relatively high reproductive rate, resulted in Merino sheep generating the highest income per hectare, compared to Afrino and Dorper sheep. Reproductive rate, mature body weight and fibre production are the primary factors determining profitability of a specific sheep enterprise. These parameters should thus be considered when changing from one breed or commodity to another. Keywords : Body weight; wool production; slaughter traits; income South African Journal of Animal Sciences Vol. 35 (2) 2005: pp.98-108

Sheep production in Indonesia has not met the demands for domestic and international markets which tends to continually increase every year. There is a significant gap between the upstream and the downstream sectors in sheep business process resulting in a stagnant supply of live sheep or their meats and co-products to the market. Unfortunately, sheep productivity in most traditional farmers is still relatively low. The local sheep are categorized as medium type in size and have several advantageous characteristics such as adaptive to the environment, resistance to ectoparasites, adaptive to low quality feed and prolific births. It is necessary to try making a huge effort to improve farming management and genetic quality of the local sheep to have high productivity and better meat quality. Garut Sheep is one of local breeds in West Java. Genetic improvement of local Garut sheep can be done by crossing them with superior type of meat sheep. It is hoped that the crossbred will inherit the superior characteristics of their two parents. Dorper is a superior type of meat sheep spread out all over the world with excellent adaptability and productivity. Therefore, HPDKI (Indonesian Sheep and Goats Farmers Association) introduced Dorper sheep (Black Head) from Australia with 8 males and 26 females to be further developed in Indonesia. The monitoring results during quarantine showed that Dorper sheep were able to adapt very well and there was no any incidence of disease. Dorper sheep were grouped into 3 groups of 8-10 females each with 1 male. The mating system was done naturally. They were fed a complete ration that has met the nutritional needs of both macro and micro nutrients. In the farm, Dorper sheep showed the following quantitative performances: averaged litter size 1.18, birth weight of single lamb 3.50 kg, birth weight of twins 2.94 kg, weaning weight of single lamb 21.43 kg, weaning weight of twins 15,50 kg, weaning age 90.05 days, Average daily gain (ADG) during lactation period 177.31 gram/head/day, lambing interval 245.91 days, gestation period 155.91 days, percentage of failed pregnancy 0.12%, percentage of male offspring 42, 50%, the percentage of female offspring 57.50%, lamb mortality 13.04%. The quantitative traits of Dorper sheep showed that the body shape was deep, wide, long and dense, no horns, a combination of fur hair and thin and short wool hair. The hair color of the head was black (20%) and the body was white (80%), the overall performance was uniform, stable and typically liked their parents. The other outstanding abilities were able to utilize low-quality feed properly with voracious nature for feed, resistance to heat stress and resistance to ectoparasites. It can be concluded that Dorper sheep is well adaptive to Indonesia tropical environment and is able to breed appropriately similar to their parents.

The objectives of the research was to analyze genetic diversity and genetic polymorphisms at Myostatin gene locus in Fat Tailed Sheep, Dorperand Texel Sheep. Research was conducted in the village area of Pandesari, Pujon District, Malang Regency, East Java Indonesia. Research was carried out in two stages, (1) field research, to observe the linear measurements of Fat Tailed Sheep, Dorper Sheep and Texel Sheep. Blood samples were taken from 91 sheep consisting of the three breeds35 (Texel, 19 Dorper and 37 Fat Tailed Sheep). (2) Laboratory research was conducted to analyze DNA polymorphism with target gene was the myostatin gene on exon 3, using PCR-RFLP analysis with Msp1 restriction enzyme was conducted to analyze polymorphism at the myostatin gene in these sheeps. The Msp1 was used to cut the mutated fragments. Data analysis used (1). Analysis of % PIC to analyze degree of polymorphism, (2) For linear measurements data such as chest girth, body length, body height, tail circumference was analysed using Minitab software version 17. Results showed that from the aspect of the phenotype, Texel, Dorper and DEG sheep have a high level of diversity, which is quite high (above 9%). The results of PCR-RFLP obtained monomorphicsite in all breeds of sheep so that the correlation between MSTN gene polymorphisms and sheep growth could not be analyzed. Because the Myostatin gene of the three breeds was monomorphic. It was concluded that the exon 3 area in all breeds was a conserved region that rarely occurs mutations.

Dorper sheep finisher ration is lacking in the Kenyan markets. The weight target is currently achieved within a longer period of approximately 2-3 years in pastoral livestock production systems. This study was carried out to formulate and test a cost-effective finisher ration for small ruminants to reach a targeted market weight of 45–50 kg within 6-7 months. Thirty entire male Dorper-weaner lambs aged 3-4 months with an average initial body weight of 23.3 kg ± 2.4 were used in a controlled on-station feeding trial. The treatments were three energy levels (9.0, 10.0, and 11 MJ ME Kg-1 DM) and three crude protein levels (12, 14, and 16% DM), with Rhodes grass hay as the control diet in a Complete Randomized Design (CRD). The response variables were feed intake (FI), average daily weight gain (ADG), total weight gain (TWG), and final slaughter/market weight. A one-way analysis of covariance (ANCOVA) for comparison of means of the response variables was conducted. The ANCOVA results of the experimental rations and control showed that FI (1.72 kg sheep-1 day-1) was statistically significant () for ration 8 (TR8 (11 MJ kg-1 DM &amp; 14% CP). The mean results indicated that TR8 had the highest ADG mean (0.31 kg/day) and TWG (26.5 kg), thus it was considered the best performing test diet (p&lt;0.05). Significant peak final slaughter weights (p&lt;0.05) in TR8 (46 kg), TR6 (43 kg), and ration 9 (41 kg) were observed at the age of about 5-6 months old. Acceptable final slaughter weights of 46–50 kg were recorded in rations TR6, TR9, and TR8. Dorper sheep receiving ration TR8 reached the highest (p&lt;0.05) slaughter weight (50 kg) at 7 months old post-weaning. In conclusion, test ration with a combination of 11 MJ kg-1 DM of energy level and 14% CP (TR8) had the highest ADG in the shortest period of 6 months old and can be recommended for adoption to finish Dorper sheep to reach market weight of up to 50 kg within 6-7 months old.

The objective of this study was to investigate the impact of the ewe’s maternal genetic merit and country of origin [New Zealand (NZ) or Ireland] on ewe reproductive, lambing, and productivity traits. The study was performed over a 4-yr period (2016–2019) and consisted of three genetic groups: high maternal genetic merit (NZ), high maternal genetic merit Irish (High Irish), and low maternal genetic merit Irish (Low Irish) ewes. Each group contained 30 Suffolk and 30 Texel ewes, selected based on the respective national maternal genetic indexes; i.e., either the NZ Maternal Worth (NZ group) or the €uro-star Replacement index (Irish groups). The impact of maternal genetic merit on reproductive traits such as litter size; lambing traits such as gestation length, birth weight, lambing difficulty, mothering ability; and productivity traits such as the number of lambs born and weaned was analyzed using linear mixed models. For binary traits, the impact of maternal genetic merit on reproductive traits such as conception to first artificial insemination (AI) service; lambing traits such as dystocia and perinatal lamb mortality; and productivity traits such as ewe survival was analyzed using logistic regression. NZ ewes outperformed Low Irish ewes for conception to first AI (P < 0.05) and litter size (P = 0.05). Irish ewes were more likely to suffer from dystocia [6.84 (High Irish) and 8.25 (Low Irish) times] compared to NZ ewes (P < 0.001); birth weight and perinatal mortality did not differ between groups (P > 0.05). Lambs born from NZ ewes were 4.67 [95% confidence interval (CI): 1.89–11.55; P < 0.001] and 6.54 (95% CI: 2.56–16.71; P<0.001) times more likely to stand up and suckle unassisted relative to lambs born from High or Low Irish ewes, respectively. NZ and High Irish ewes had a greater number of lambs born and weaned throughout the duration of the study compared to their Low Irish counterparts (P<0.001). NZ ewes tended to be more likely to survive from one year to the next compared with Low Irish ewes (P=0.07). Irish ewes of high maternal genetic merit outperformed their low counterparts in total number of lambs born and weaned per ewe, but performance did not differ across other traits investigated. This highlights the importance of continuous development of the Irish maternal sheep index to ensure favorable improvements in reproductive, lambing, and productivity traits at the farm level. Overall, results demonstrate the suitability of NZ genetics in an Irish production system.

The study was conducted in Hawzen and Hintalowagerat districts of Tigray region Northern Ethiopia with the objective of enhancing meat production performance of the local sheep through cross breeding with high yielding exotic Dorper sheep under smallholder farmers. Pure male Dorper mated with local sheep produced first and second generation with 50 and 25% blood level of Dorper, respectively. Farmer&rsquo;s research groups were established in both locations. The average live body weight of the 50% crossbred male and female sheep was 45 and 38 kg, respectively at adult age. The average live body weight of the adult male and female local sheep (highland) was 25 and 20 kg, respectively. On farm crossbreeding of Dorper (male) sheep with local sheep (female) improved body weight by 55% (male) and 53% (female) at yearly age. Smallholder farmers perceived that Dorper crossbred sheep are appropriate for meat production improvement. It is concluded that regardless of the black body color and the appearance short thin tail of the crossbred, Doper sheep breed is the appropriate technology for enhancing meat production performance of the local sheep. &nbsp; Key words: Crossbreeding, Dorper sheep, meat production, local sheep.

Ten Dorper (16.0 to 37.0 kg) and Local (12.0 to 28.5kg) rams were used to determine the voluntary intake, digestibility, nitrogen retention of maize stover and live weight change. Dietary treatments were maize stover offered to meet the requirement for maintenance with urea lick, 1.5 or 2 times maintenance with urea lick. Stover stems had higher fibre content (78.5 % NDF) and lower content of nitrogen (0.34 %) and metabolizable energy than leaves. The sheep consumed leaves and rejected all stems. Intake of maize stover increased (P < 0.001) with increasing level of feed offered above maintenance. Sheep offered stover at 1.5 times maintenance had highest intake of stover (24.7 g/kg body weight) and nitrogen (1.5 % feed intake). There were no differences in intake between levels higher than maintenance. Digestibility was highest (P < 0.01) for sheep offered stover at 1.5 times maintenance. Higher nitrogen intake of stover diet increased digestibility and intake of dry matter owing to the stimulation of microbial activity. Liveweight gain was higher (P < 0.05) for sheep offered stover at 1.5 times maintenance (52 g/day) reflecting high intake, while sheep offered stover at maintenance lost weight (-105 g/day). Metabolizable energy intake increased with increasing total dry matter intake. Nitrogen balance was positive for diets with nitrogen intake of more than 1 % of feed intake. Nitrogen retention increased with high nitrogen intake. Breeds did not differ in voluntary intake. Dorper sheep had higher digestibility, higher nitrogen retention and gained more weight than local sheep (P < 0.001). It was concluded that for sheep fed low quality maize stover, voluntary intake, digestibility, nitrogen retention and liveweight gain increased by offering greater amounts of stover with high nitrogen intake (1 % feed intake). Differences in digestibility suggest that the Dorper breed could be a valuable resource for sheep production even in areas where low quality maize stover limit the use of European breeds.UNISWA Jnl of Agric Vol 8 1999: pp 44-49

The aims of present study was to evaluate the qualitative and quantitative characteristics of imported sheep such as Texel crossed and Dorper sheep, compared with local sheep (Fat Tail Sheep/FTS) in almost the same region, namely Pujon and Karangkates. This research was a field research with case study methods and research materials as many as 39 for Texel crossed sheep, 19 for Dorper sheep and 37 for FTS. The age of the sheep ranges from 1.5 to 3 years (some have their first calf). Qualitative data were analyzed by Population Genetics Analysis and quantitative data were analyzed by One-Way Design Anova using Minitab software version 13. The results showed that: (1) Qualitative traits in Texel crossed , Dorper and FTS sheep showed that some traits underwent fixation where one of the traits was fixed. One allele in Texel crossed and Dorper sheep has disappeared and no longer exist in its origin place such as horned and hornless traits, white body color and black head, erect ears, while in FTS sheep it is still polymorphic, especially in the hornless and drooping ears in FTS. The white color on the FTS seems to have been fixed, because the dominant gene frequency/ p = 1 and the recessive gene frequency/ q = 0. (2) The quantitative traits such as body weight, in which the body weights of the Texel crossed , Dorper and FTS breed were different in the study, and the Dorper sheep the highest body weights, while the body weights of Texel crossed and FTS sheep were almost the same. Dorper sheep had the highest head index, and Texel crossed sheep and FTS sheep had the same head index. It was concluded that Texel crossed and Dorper sheep had many fixed qualitative characteristics such as horns, erect and drooping ears, white body color and black head in FTS sheep were quite polymorphic in horns and erect and drooping ears. The best growth of Dorper sheep because Dorper sheep was originated from a crossing between Dorset and Black Persian sheep.

ABSTRACTBackground and Aim:Sheep farming is a vital component of Indonesia’s agricultural economy, where the demand for meat continues to rise. Indigenous Garut sheep are well-adapted to local environments and are known for their high reproductive efficiency, but they have low growth rates. Conversely, Dorper sheep are renowned for their rapid growth and carcass quality, but they exhibit longer lambing intervals under tropical conditions. Crossbreeding offers a strategy to combine the strengths of both breeds. This study aimed to evaluate maternal reproductive performance and pre-weaning growth traits in purebred Dorper, Garut, and Dorper × Garut crossbred sheep under a commercial breeding system in Indonesia.Materials and Methods:A retrospective observational study was conducted on 1,744 ewes (1,498 Garut, 209 F1 Dorper × Garut, and 93 Dorper) and 3,248 lambs (2,846 F1 Dorper × Garut, 253 B1 backcrosses, and 149 Dorper) from a commercial enterprise in West Java. Data included lambing interval, litter size, birth weight, weaning weight, pre-weaning mortality, average daily gain (ADG), reproductive index, and productivity index. Statistical analyses employed one-way analysis of variance with Duncan’s multiple range test for post hoc comparisons.Results:F1 Dorper × Garut crossbred ewes demonstrated significantly shorter lambing intervals (206.65 ± 2.75 days) than pure Dorper (265.66 ± 1.14 days), comparable to Garut ewes (209.10 ± 1.08 days). However, Garut ewes had superior litter size (1.77 ± 0.18) relative to both crossbred (1.33 ± 0.04) and Dorper ewes (1.30 ± 0.42). In growth performance, Dorper lambs excelled in birth weight (3.35 ± 0.07 kg), weaning weight (23.93 ± 0.57 kg), and ADG (203.88 ± 4.65 g/day). F1 Dorper × Garut lambs showed significantly higher weaning weight (19.48 ± 0.35 kg) and ADG (165.34 ± 2.95 g/day) compared with Garut lambs (15.36 ± 0.10 kg; 130.47 ± 0.83 g/day).Conclusion:F1 Dorper × Garut crossbreeding synergizes Garut’s reproductive efficiency with Dorper’s growth performance, yielding crossbreds well-suited for tropical meat production. While Garut maintains a prolificacy advantage, F1 crossbreds deliver improved pre-weaning growth, supporting their use in commercial fattening programs. Maintaining pure Garut flocks for breeding and employing F1 crossbreds for production may enhance productivity and sustainability in Indonesia. Future research should assess carcass traits, multigenerational crossbreeding, and economic feasibility.

Effects of behavioral reactivity on production and reproduction traits in Dorper sheep breed

This study evaluates the growth performance of Dorper × indigenous crossbred sheep under semi‐intensive management system and assesses farmers’ perceptions toward these crossbred lambs in southern Ethiopia. Performance data, namely, birth weight (BWT), weaning weight (WWT), and average daily weight gain from birth to weaning (ADG0‐3), were collected from Mente Dubo breed evaluation and distribution (BED) site. To gather comprehensive information on sheep production systems and farmers’ perceptions, on‐farm surveys were conducted in the Damot Pulasa, Damot Gae, and Damot Sore districts of Wolaita Zone using semistructured questionnaires. Data were analyzed using different procedures in Statistical Package for Social Sciences (SPSS) software. Analysis of growth performance revealed that, under the semi‐intensive management system, the least squares means (LSM) for BWT, WWT, and ADG0‐3 were 2.84 ± 0.06 kg, 15.40 ± 0.90 kg, and 137.78 ± 99 g/day, respectively, with a preweaning survivability rate of 77.7%. Farmers primarily raised sheep for income generation (index = 0.28) and as a form of savings (index = 0.25). Farmers expressed a preference for Dorper crossbred lambs due to their faster growth rates (odds ratio [OR] = 1.95, p &lt; 0.05) and docile behavior (OR = 2.12, p ≤ 0.01). However, challenges such as increased susceptibility to disease and color‐related drawbacks were also identified. In conclusion, there is a possibility of continuing cross‐lamb production and disseminating it to selected pocket areas within the study areas. The breed could be promoted as an optional genetic material. To ensure better survival of crossbred lambs, it is important to integrate improved management systems, such as enhanced feed, housing, and healthcare.

Genetic correlations between reproductive and productivity traits of ewes and their early growth, wool production and worm resistance traits were estimated among 2460 crossbred ewes. The ewes were progeny of 74 maternal breed sires and mainly Merino dams. The ewes were born over 3 years and had three joinings with a total of 6824 ewe joining records. The reproductive and ewe productivity traits included: (i) fertility (ewes lambing per ewe joined); (ii) litter size (number of lambs born per ewe lambing); (iii) rearing ability or lamb survival (lambs weaned of lambs born for lambing ewes); (iv) number of lambs born (NLBj) per ewe joined; (v) number of lambs weaned (NLWj) per ewe joined; (vi) total litter weight weaned (TWWj) per ewe joined; and (vii) the component trait average lamb weaning weight in the litter (AWW). The growth traits included the weight of the ewe at birth (BWT), weaning (WWT) and postweaning (PWWT), as well as growth rate pre- and postweaning. The wool traits included greasy (GFW) and clean fleece weight (CFW), yield and average fibre diameter (FD) at their first adult shearing. Worm egg count (WEC) during their first year was also recorded. Bivariate mixed models analyses using ASReml procedures were used to estimate the genetic correlations. The genetic correlations between TWWj and growth traits were positive and moderate to high and ranged from 0.34 for BWT to 0.61 for PWWT. Those for the other composite reproductive traits were slightly lower and ranged from 0.27 to 0.54 for NLWj and from 0.07 to 0.46 for NLBj. The genetic correlations between the overall measures of reproduction (NLBj, NLWj and TWWj) and GFW, CFW and FD were negative and generally low to moderate (–0.21 to –0.52). The correlations were generally larger for NLBj than for NLWj and TWWj. The genetic correlations between the reproductive traits and WEC were close to zero, except between AWW and WEC (0.42). The phenotypic correlations between the reproductive traits and the growth, wool and WEC traits were all close to zero. The genetic correlations were generally favourable between ewe reproduction and growth, with early selection for traits such as WWT and PWWT likely to give some improvement in subsequent reproduction and ewe productivity. In contrast, there appears to be a slight antagonism between reproduction and wool production. This study provides estimates of genetic correlations from crossbred ewes that add to the limited knowledge of these parameters that will improve the accuracy of genetic evaluation and prediction of the outcomes from breeding programs for meat and wool objectives that include reproduction.

This study retrospectively investigated the effect of breed and season on the lambing/kidding dynamics, growth performance, neonatal viability, and weaning dynamics of sheep (Damara, Dorper, and Swakara) and goats (Boer goat and Kalahari Red) at a farm in the Khomas Region of Namibia between 2004 and 2015. Litter size was dependent on breed (X2(12, N = 3388) = 796, p < 0.001), with twinning more frequent in Dorper sheep and Kalahari Red and Boer goats than in the Damara and Swakara sheep (p < 0.05), while triplets were more prevalent in the Dorper sheep and Kalahari Red goats (2.8% and 1.0%, respectively; p < 0.05). Distribution of birth weight categories was dependent on breed. There was a significant difference in the proportions of birth weight categories between breeds (X2(12, N = 3388) = 467, p < 0.001) whereby Dorper lambs were mostly born weighing below 3kg (2.6%, p < 0.05); Boer goat kids, Kalahari Red kids, and Damara lambs were mostly born weighing 3 to < 4kg (4.3%, 6.3% and 19.9%, respectively; p < 0.05); Swakara lambs were mostly born weighing 4 to < 5kg (12.2%, p < 0.05), and Swakara lambs were mostly born weighing ≥ 5kg (3.3% and 2.3%, respectively, p < 0.05). Weaning age categories were dependent on breed (X2(12, N = 3388) = 241, p < 0.001) whereby Dorper lambs were mostly weaned at below 3months of age (2.8%, p < 0.05); Damara lambs were mostly weaned at 3 to < 5months of age (12%, p < 0.05), and Boer goat kids were mostly weaned at ≥ 5months of age (0.9%, p < 0.05). Neonatal viability was dependent on breed (X2(8, N = 3388) = 49.2, p < 0.001) whereby Dorper lambs were more susceptible to abortions and neonatal deaths (0.6% and 1.5%, respectively; p < 0.05) than the rest of the breeds. Breed and lambing season interacted to produce effects on the birth weight of offspring although lambing season alone did not have a significant effect on Boer goat and Kalahari Red kids' birth weights.

Muzaffarnagari, the heaviest breed among 43 Indian sheep breeds, is originally distributed in and around Muzaffarnagar district of western Uttar Pradesh and also in some parts of Rajasthan, Haryana and Delhi states. Muzaffarnagari is a mutton type breed because the wool production is low and wool quality is very course, not suitable for carpet manufacture. To study the impact of various factors on production and reproduction traits, the data on 1080 Muzaffarnagari lambs born under Network Project on Sheep Improvement during years 2011-15 at ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura (UP) were recorded for growth traits i.e. body weights at birth, 3, 6, 9 and 12 month age, wool production traits viz. greasy fleece yields of lambs in first and second six monthly clips and reproduction traits viz. tupping, lambing on available basis, lambing on bred basis, twinning and replacement rate of ewes. The overall least squares means for body weights at birth, 3, 6, 9 and 12 months age were 3.55±0.02, 16.02±0.12, 24.46±0.18, 29.18±0.19 and 33.52±0.19 kg, respectively and average daily gains (ADGs) during 0–3, 3-6, 6-12 and 3-12 months age groups were 138.56±1.27, 92.18±1.22, 63.87±0.64 and 50.89±0.86g, respectively. The overall least squares means for lambs 1st and 2nd six monthly clips 533.23±5.47 and 544.43±5.94g, respectively. The effect of sex, year of lambing, parity and type of birth of lambs had highly significant (P 0.01) influence on all growth and wool production traits except non significant effect of year on birth weight, parity on 3-6, 6-12 and 3-12 months ADG, type of birth on 3-6 month ADG, sex on lambs first clip and type of bith on lambs second clip. On comparison, male lambs were found superior than female lambs for all body weights and fleece yields. During year 2013, all the body weights and greasy fleece yields were recorded to be highest. Parity of ewes did not show any definite trend for growth traits while type of birth indicated that lambs born as single gained heavier weights at all growth stages and produced heavier clips than multiple born lambs. Tupping, lambing on available basis, lambing on bred basis, twinning and replacement rate ranges from 86.9-100.0, 74.3-91.0, 83.2-92.5, 10.9-20.3 and 24.5-33.2%, respectively. This study revealed that 0-3 month lambs growth is very crucial which needs proper management, feeding and health care and selection of breeding rams based on their six month body weight was effective for genetic improvement of Muzaffarnagari sheep for growth and reproduction traits.