Factors affecting the early growth and survival of indigenous Ethiopian Horro sheep were identified and the influence of each was assessed, based on data collected from 1978 97 from 4031 lambs at Bako Research Centre, Ethiopia. Year of birth, sex, type of birth or rearing, and parity had significant (P < 0.01) effects on birth weight (BWT), weaning weight (WWT), and six month weight (6MWT). With the exception of parity, the same factors affected yearling weight (YWT). Male lambs were heavier by 0.14, 1.1, 1.9, and 4.2 kg than females in BWT, WWT, 6MWT, and YWT. Single born lambs were heavier by about 0.5 kg than multiple born lambs at birth. Lambs born from primiparous ewes were lighter by 0.2 0.3 kg than lambs born from multiparous ewes at birth. With the exception of effect of type of birth and ewe age on survival to 3 and 7 days of age, respectively, year of birth, ewe (dam) age, type of birth, and BWT had significant (P < 0.01) effect on survival from three days to one year of age. The survival of multiple-born lambs was 0.8, 3.7, 8.3, 12.2, and 12.496 lower than single-born lambs at the age of 3, 30, 90, 180, and 365 days, respectively. Lambs born from primiparous ewes had lower survival rates compared to those born from multiparous ewes. Survival was very low in lambs with low BWT and improved with increase in BWT. In general, there are indications that there exists a critical BWT (about 2.6 kg) below which the survival of lambs declines drastically.

The study was conducted to assess the reproductive performance of ewes under village management condition in south western part of Ethiopia. The study was a monitoring study which took place for three years (1995-1997). The overall least squares means for lambing interval (LI) and annual reproductive rate (ARR) were 262 ±53.4 days and 1.88 ± 0.44, respectively. The overall least squares means of age at first lambing and litter size were 404 + 65.40 day and 1.21+1.45 lambs, respectively. Lambing interval was significantly (P<0.05) influenced by parity of the ewe, type of birth and year of lambing. The ewes at their first, and six and above parity showed longer subsequent lambing interval than ewes at 2-5 parity. Ewes that suckled singles had shorter subsequent lambing interval than ewes which suckled twins (255+3.74 vs 283+5.72 days). Year of lambing and type of birth exerted a significant effect (P<0.05) on ARR. The ewes that dropped twins had higher ARR than ewes which dropped singles (1.52 Vs 2.56 lambs/ewe/year). Litter size was significantly (p<0.05) influenced by season of lambing and parity of the ewe. There was a tendency that, litter size increased with an increase of parity up to fifth parity and dropped at the sixth and more parities. The reproductive performance of ewes under village management condition is discussed in association with reports elsewhere in the tropics.

The feed resources base, the feeding systems and feed values of three indigenous trees Girawa, Anfare and Kelewa (Local (Amharic), Ethiopian names ) were studied for sheep in sub humid, mid altitude area of south western Ethiopia. The study involved a survey of the feed resources base and assessment of the feeding systems, chemical analysis and in vitro dry matter digestibility. In addition, Girawa was selected to study its effect on growth performances using 32 lambs. The levels of Girawa used for the growth performance study in groups I, II, III and IV, respectively were 100 g/d, 200 g/d, 300 g/d and 400 g/d. The main feed resources for sheep in Jimma area were found to be natural pasture, crop residues, crop aftermaths and indigenous multipurpose trees. Grazing on natural pasture constituted the main feeding system. The indigenous trees were cut and fed occasionally. The levels of CP ranged from 186.2 to 244.4 g/kg DM with minimum level in Anfare. Higher values were recorded for Girawa. Organic matter content was higher for Anfare (924.3 g/kg DM) and lower for Girawa (877.9 g/kg DM). In vitro dry matter digestibility values were 0.448, 0.422 and 0.458 for Girawa, Anfare and Kelewa, respectively. Supplementation of Girawa had an effect (p<0.01) on live weight gains of lambs. Lambs that were offered 400 g/d of Girawa had a higher daily live weight gain (95.1 g/d) compared to those supplemented with 200 (43.3 g/d) and 300 g/d (50.5 g/d) of Girawa as well as the control group (34.0 g/d). Weight gains were not different between the control group and those supplemented with 200 and 300 g/d of Girawa. It was concluded that these feed resources represent a great potential for sheep production in areas where the resources are available. It is also suggested that more studies are needed on higher level of Girawa than the present study on animal performances along with its anti-nutritional effects.

The study was conducted to assess the growth performance of lambs under village management condition in Jimma, Ethiopia from 1995 to 1997. The overall mean body weight at birth, at weaning (180 days) and up to a year (360 days) was recorded to be 2.45, 18.8 and 25.4 kg, respectively. The overall mean growth rate up to weaning weight (180 days) and up to one year old (360 days) was 92.3 and 68.3 g/day. The non-genetic factors such as season, yea, sex, parity, litter size and district were considered in this study. The main factors had a significant effect (at least p<0.05) on weight for age and weight gains recorded. A consistent significant effect of sex and birth type (single/twin) (p< 0.05) was observed for weight for age and growth rates. The males were heavier than females, by 7.11% and 10.2 % for 180 days and 360 days weight, respectively. The twins were lighter than singles by 20.1 % and 8.32% for 180 days and 300 days weight, respectively. The effect of parity was significant (p<0.05). The lambs born to ewes at first parity had lower weight for ages and weight gains compared to subsequent parities. The lambs born in land scarce area (Dedo district) had lower weight gains than lambs born in Seka (land better area). Differences were significant (P<0.05) and weight gain recorded at 180 days were 85.3 and 90.9 g/day for Dedo and Seka lambs, respectively. The variation in growth performance of sheep in different districts could provide base line information to set a long-term genetic improvement plan by election. The results are discussed in comparison with data obtained from elsewhere in the tropics.

The study was undertaken to evaluate the efficiency of selection on growth performance of Menz sheep under a community-based breeding program (CBBP) from the period of 2009 – 2017. A total of 3996 lamb records (ram lambs 2025/ ewe lambs 1971) were used to evaluate the phenotypic and genetic factors affecting the growth traits of Menz sheep. REML in Wombat and General linear model on SAS (version 9.0) were used to evaluate selection efficiency for growth of Menz sheep. The least squares means and standard errors on phenotypic growth weight for birth, weaning age, six month age and yearling age were 2.58±0.004, 8.99±0.02, 13.28±0.02 and 19.94±0.06 kg, respectively. The effect of sex was significant (p<0.001) only for birth weight and no significance effect (p>0.05) was observed for weaning, six month and yearling weights. All growth traits were not affected by fixed effect of parity and birth type in this particular study. However, birth season and birth year had a great influence (p<0.0001) on all growth traits. The genetic trend on estimated breeding values (EBV) was not consistent across years and varied between sexes. The highest EBV for weaning, six month and yearling were recorded for the year 2013 and the lowest in 2009 (at weaning and six month) and 2015 (at yearling).The female EBV (at weaning, six month and yearling) was higher than male for the current (2017) and base population (2009).The responses to selection as compared to base population (2009) for birth, weaning, six month and yearling weight were – 0.00446Kg, + 0.11Kg, + 0.54Kg and + 0.75Kg respectively. This study indicates that improvement in body weight for Menz sheep through CBBP is possible; however, the response to selection varied across years and its pattern was irregular for the implemented years due to the problem on selection of breeding rams (lower availability of breeding rams) and management effect.

The influence of non-genetic factors on lamb survivability at various ages up to 360 days was studied under village management condition in Jimma, Ethiopia. The overall least squares means of lamb survival rate was 89.0 at 0-60, 81.5 at 0-120 and 50.0 % up to 360 days. The survival rate of lambs up to weaning (120 days) was 81.5 %. Season of birth consistently exerted a significant effect (p<0.05)) on lamb survival. Lambs born during the post rain and dry periods showed a higher survival rate than lambs born during the wet season. Districts showed a significant effect (p<0.05)) on survival rates of lambs. Lambs born in land scarce areas (Dedo) had a low survival rate than lambs born in Seka (land available area). Type of birth did not exert an influence (p>0.05) on lamb survival. Sex had a significant effect (p<0.05) on survivability of lambs at later stages and the females showed higher survivability rate than males. Mortality tended to decrease with an increase with birth weight and decreased as parity increased. The birth weight showed a significant effect (p<0.05) on survival rate of lambs. The lambs with birth weight of 2 kg and above were showing higher survival rate. The lambs with 1.5 kg and lower birth weight showed high mortality rate. The study revealed that, adequate measures to be taken to curb mortality of lambs. The selection of heavier weight and larger litter at birth coupled with improved management could be a means to improve lamb productivity in the villages.

The article discusses the results of comprehensive studies histomorphological signs of skin and hair of sheep (Degeress) of various stripes, especially the thickness of the skin and its layers that are commonly identified indicators. Studies allow to bring the scientific basis for the proper development of activities aimed at increasing production of wool, quantity and quality of which skin microstructure largely depends on. Sheep of different colors have a specific feature on the histological structure of the skin, which is essential for the development of effective methods of selection that enhance productivity of sheep wool. The researches have established that brown suit sheep has thickened skin as compared to red and gray color (p is less than 0.01). In turn, pilar layer of the skin is also much thicker at brown coloration sheep (2029.7 ×10E-6 m) than in sheep red (1850.6×10E-6 m) and sulfur (1773.7×10E-6 m) suits, the difference is statistically highly significant (p is less than 0.001). The thickness of the pilar layer is up to 70% of the dermis, which varies depending on sheep lear ranging from 1773.7×10E-6 m to 2029.7×10E-6 m. Reticular layer thickness varies depending on sheep lear ranging from 743.5×10E-6 m to 826.4×10E-6 m.

This study investigates different environmental effects on birth weight, weaning weight, and pre-weaning daily gain using different statistical models in the Latvian sheep population. The coefficients of determination (R2) were used to estimate the extent of different non-genetic factors influencing birth weight, weaning weight, and pre-weaning daily gain. Data were collected of 4460 lambs born in 36 herds during 2008 to 2010. The birth weight (on average 4.1 ± 0.01 kg), weaning weight (on average 21.0 ± 0.07 kg) and pre-weaning daily gain (on average 242.1 ± 0.93 g) was significantly affected by type of birth and sex, lambing age of dam (covariate) and herd, year, season of birth (p is less than 0.01). Coefficients of determination were estimated from 0.14 to 0.42 for birth weight, from 0.13 to 0.49 for weaning weight, and from 0.10 to 0.46 for pre-weaning daily gain. The results show that when the fixed effects of HYS (interaction between the herd, year, and season of birth) were included it improved the quality of the statistical model most of all, because higher determination coefficients were obtained for all traits: 0.42 for birth weight, 0.49 for weaning weight, and 0.46 for pre-weaning daily gain.

The aim of the present study was to estimate variance and covariance components and genetic parameters for birth, weaning and yearling weights. The data were collected from lambs who born in period from 2007 to 2010 years and located in 58 pure-bred sheep herds in Latvia. Records of 11310 lambs from 160 rams and 4180 ewes for birth and weaning weight and on 3194 lambs from 134 rams and 2058 ewes for yearling weight were used in this study. The total number of individual pedigree was 18932. The fixed effects in the model were sex and type of birth, birth year and month and age of dam, because all growth traits were significantly affected by these fixed effects (p is less than 0.01, p is less than 0.05). Genetic parameters for growth weights were estimated by Restricted Maximum Likelihood (REML) procedure fitting three animal models including various combinations of maternal and herd effects. Based on the most appropriate fitted model which included additive genetic, maternal additive genetic and herd effect, direct heritability’s were estimated to be 0.26 ± 0.01, 0.29 ± 0.63, 0.29 ± 2.63, but maternal heritability’s 0.14 ± 0.00, 0.04 ± 0.19, 0.04 ± 0.94, respectively for birth, weaning and yearling weights. The results showed maternal and strong herd influence in this study, therefore inclusion of maternal and herd effects into the model for growth traits is necessary.