On-farm performance evaluation of indigenous sheep in the Gedeo zone, Southern Ethiopia

ABSTRACT

This study was conducted to identify the productive and reproductive performance of sheep in the Gedeo zone. Flock of 50 households was randomly selected for a household survey. A total of 189 lambs’ growth data and reproductive traits from 125 ewes were collected. A general linear model was employed for the analysis. Sheep flock size shows (8.6 ± 0.11) a significant difference (P < 0.05) among age categories. Weight at birth (3.01 ± 0.3 kg), weaning (14.2 ± 0.9 kg) and six months (22.4 ± 1.1) of lambs were significant (P < 0.01) among parties, birth type, lamb sex and birth season. Body size and growth rate were important traits for breeding sheep selection. The average age at first lambing and lambing interval was 12.3 ± 0.12 and 7.7 ± 0.06, respectively. Other reproductive traits, such as fertility rate (76.7%), litter size (1.51), weaning percentage (81.6%) and lamb survival rate (86.2%), were observed. In conclusion: parity, birth type, lamb sex and birth season are important sources of variation in sheep growth performance that were considered fixed effects during the analysis. Thus, as policy direction, genetic improvement combined with nutrition, health and participatory breeding would contribute to sheep genetic improvement that should be given proper attention.

KEYWORDS:

• Growth traits
• lambs
• parity
• weaning rate

1. Introduction

Livestock is a crucial component of many economies and livelihoods, with sheep being the most prevalent (Roessler 2019). In Ethiopia, sheep production is the major component of the livestock sector and owing to a large population of 42.9 million, of which about 70% are females and 30% are males (CSA 2021). The production of manure, skins and wool is an important activity for smallholders as they contribute to direct cash income, serve as insurance and provide valuable resources (Solomon et al. 2010; Menegesh 2012). These characteristics of sheep that contribute to the economic value are necessary for the development of livestock breeding programmes (Abd-Allah et al. 2019). Compared to cattle, sheep have shorter production cycles, faster growth rates, more ease of management and lower capital investment (Tadesse et al. 2015). Sheep productivity is influenced by various factors, such as age, season, management, nutrition, genetics, body condition, uterine capacity, ewe’s health and environment (Ajafar et al. 2022; Al-Thuwaini and Al-Hadi 2022; AL-Jaryan et al. 2023). Sheep productivity can also be affected by litter size, lambing interval and age at first lambing. Besides litter size the sex of lambs, can affect the ewe’s productivity. During gestation, male animals appear to have a faster growth rate than female one (Taye et al. 2010). This is because of the anabolic protein effect of androgens, and androgen hormones in male animals can stimulate growth, so male animals can be larger than females (Ibrahim et al. 2020). Lamb survivability farmers’ condition is one of the main factors that affect lamb production (Belay and Haile 2011). The same authors also indicated that higher survival rates are essential for the replacement of stock and efficiency of selection.

Reproductive traits, such as age at first service, age at first lambing, birth type and lambing interval, have high economic value in all sheep production systems (Yavarifard et al. 2015). The reproductive performance of sheep together with survival and growth traits is a key factor determining the efficiency of flock productivity and needs to be recorded for genetic and management improvement (Ashebir et al. 2019). On-farm performance evaluation contributes a more representative level of the breed performance since it is undertaken under the natural production environment of the breed (Gizaw et al. 2011). However, no detailed information is documented on sheep production and reproduction performance and farmers breeding objective to design genetic improvement under smallholder farmers in the Gedeo zone. Therefore, this research was conducted to measure the productive and reproductive performances of sheep in the Gedio zone to improve the sheep genetic potential of the area.

2. Materials and methods

2.1. Study area

The study was conducted in the Gedeb district of the Gedeo zone of southern Ethiopia. Gedeb is one of the districts in the Gedeo zone, which has a high number of sheep populations. From the Gedeb district, depending on their flock size and accessibility, Harmufo kebele¹ (Figure 1) was selected purposely. Agro-ecologically, the district is classified as highland (75%) and midland (25%). Astronomically, the district is located at 7° 19’ North latitude and 39° 17’ 0” East longitude. The altitude ranges from 2250 to 2367 m asl. The main livestock species reared in the district include cattle, sheep, poultry, honeybees and horses.

Figure 1. Map of the study area, Gedeb, Southern Ethiopia.

2.2. Sampling techniques and data collection procedure

2.2.1. Animals and household selection techniques

A total of 50 sampled households who have three or more ewes were randomly selected for the household survey. Initially, 163 ewes were selected from sampled households for monitoring and data collection. The identified ewes were marked using plastic ear tags. During the selection, age and parity (1–5 level) were determined by dentition and farmers’ recall method. The ewes were mated with the available rams in the area. To monitor and record data, one enumerator was trained and assigned.

2.2.2. Data source

Both primary and secondary data were collected from the available sources. The primary data were collected from sample households using interviews with the help of a structured questionnaire. The structured questionnaire was used to collect information on socio-economic characteristics, sheep breeding objectives, feeds and feeding systems, mating systems, farmers’ trait preferences, reproductive performances (age at first lambing, lambing interval) and major challenges in sheep production. Secondary data were obtained from the Zonal and District offices of the Agricultural Department. Intensive training was given for data collectors and development agents related to growth performance data collection techniques.

2.2.3. Monitoring

A total of 125 births and 189 lambs (98 males and 91 females) were collected from April 2020 to September 2021. New-born lambs were marked with plastic ear tags. Growth data in birth, 3 month, and 6 months weight were collected and measured using a suspended 50 kg balance. Birth type, lamb sex, dam parity and birth season were taken within 24 h of birth. The survival rate of lambs from birth to weaning was also recorded.

2.2.4. Management of animals

Animals were managed according to farmers’ management practices with no special feeding or any other management intervention. The ewes were allowed to graze on free communal grazing land. Some farmers give supplemental feeds (straws, salt and enset² leaves) for the pregnant, nursing ewes and suckling lambs. They are also watered once per day.

2.3. Data analysis

Data were analysed using the General Linear Model (GLM) procedure of SAS and means of significant effects were separated using Tukey’s honestly significant difference (HSD) test at P < 05. Frequencies and percentages were used to describe qualitative data. Considered response variables were lamb birth, weaning and six-month day’s weight. Fixed effects fitted in the model were sex (male, female); parity (1–5); birth type (single, twin) and season (wet, dry).

The general linear model is specified as (1) $Y_{\mathrm{ijkl}}=\mu +S_i+B_j+P_k+T_l+{ϵ}_{\mathrm{ijkl}}$(1) where

• Y_ijkl =Response variable

• μ =  overall mean of the respective variable.

• S_i =  the effect of i^th sex (male, female).

• B_j =  the effect of j^th birth type (j = single, twin).

• B_k= the fixed effects of the k^th parity (k = 1, 2 … 5)

• T_l=  the effect of _l^th season (l = dry, wet)

• Є_ijkl =  random error term.

Parameters, like weaning rate,³ fertility,⁴ survival rate⁵ and litter size,⁶ were computed on a percentage basis.

The purpose of keeping sheep, breeding rams and ewes selection criteria based on farmers’ traits of interest were analysed using the index method of ranking analyses (Musa et al. 2006). (2) $\mathrm{Ranking}\mathrm{index}={\displaystyle \frac{\mathrm{Rn}\ast C1+\mathrm{Rn}-1\ast C_2\dots +R_1\ast \mathrm{CN}}{\sum \mathrm{Rn}\ast C_1+\mathrm{Rn}-1\ast C_2\dots +R_1\ast \mathrm{CN}}}$(2) where

• R_n= the last rank (if the last rank is 5, then R_n-1 = 4), R_1 = 1

• C₁ … _N =  per cent of respondents ranked first to last

3. Results and discussion

3.1. Socio-economics characteristics of households

Age and education levels of the sample households are presented in Table 1. The study revealed that the majority of households were male-headed. The majority of the respondents were illiterate and had not attended formal education (i.e. 54%). About 22% of the respondents can read and write and the remaining (24%) attended primary and junior school. Education is instrumental in affecting household farm income, adopting technologies, taking health care and for the betterment of the socio-economic status of the family (Paltasingh and Goyari 2018). In line with this study, a higher proportion of illiterate households (79.4%) and lower levels of primary school (2.4%) were reported in Jeldessa, Ethiopia (Kebede 2009). In contrast to the present study, in the rural agro-pastoral areas of Uganda majority of (i.e. 84.1%) household heads had attained formal education (Byaruhanga et al. 2015).

Table 1. Household head and educational status (N = 50).

Parameters	N	%
Household head
Male	41	82
Female	9	18
Educational level
Illiterate	27	54
Read and write	11	22
Primary school (grades 1–6)	4	8
Junior school (grades 7–8)	8	16

3.2. Livestock composition

Average livestock possessions per household are presented in Table 2. Accordingly, the average sheep population was 8.6 ± 0.13 heads per household, followed by cattle and chicken. Livestock holding in the study area was relatively close to the report of Shimelis (2012), 8.1 heads per household in Sidama, southern Ethiopia. Unlike the present study, those reported by Mekonnen et al. (2012) in western Oromia and Altaye et al. (2014) in Metekel zone farmers possess more cattle than other livestock species. The reasons might be that farmers own more sheep than other livestock species where sheep serve as an immediate source of income and have short generation intervals, high prolificacy and low space and feed requirements. This large flock size of sheep would encourage sheep improvement through selection.

Table 2. Average livestock possessed per household (N = 50).

Livestock species	Min	Max	Average
Cattle	1	5	2.5 ± 1.9^b
Sheep	3	14	8.6 ± 0.13^a
Goat	0	1	0.01^d
Donkey	0	1	1.41^c
Horse	0	1	1.1^c
Chicken	2	4	2.2 ± 1.3^b

^a–d Means with different subscript letters across the rows are significantly different (P < 0.05).

3.3. Sheep flock size and composition

Sheep flock size and composition are presented in Table 3. As shown, the proportions of breeding ewes were significantly (P < 0.05) higher among the sheep flock followed by lambs less than 6 months and ewe lambs. However, breeding rams were significantly (P < 0.05) lower among the sheep flocks. Similarly, Getachew et al. (2010) reported that breeding ewes were dominant taking a major portion of Menz sheep (north Ethiopia) flocks. The larger proportion of breeding ewes would imply the production of more lambs, which in turn might increase the intensity of selection and marketable lambs (Taye et al. 2010). Ram to ewe ratio (i.e. 1:19) obtained in the current study was higher than that reported by Amare et al. (2019) (1:13.9) in Setit Humera (west Ethiopia) sheep. As confirmed during the flock monitoring period and group discussion, the male sheep were removed from the flock at an early age, but farmers were accustomed to retain female sheep in the flock as replacement stock. The possible reasons for selling immature rams are (1) farmers have low awareness about breeding ram selection (2) urgent households’ socio-economic needs of money, for example, to pay children’s school fees (3) purchasing agricultural inputs (fertilizer, agrochemicals) and (4) to pay government tax for owned farmland.

Table 3. Sheep flock size and composition (mean ± SE).

Sheep flocks	Average	Proportions (%)
Breeding ewes >1 year	3.8 ± 0.9^a	44.4
Breeding rams >1 year	0.2 ± 0.1^d	2.4
Ewe lambs 6 month-1year	2.1 ± 0.6^b	24.7
Ram lambs 6 month-1 year	0.3 ± 0.1^c	3.5
Lambs less than 6 months	2.21 ± 0.4^b	25
Overall	8.51 ± 0.84	100
Breeding ram to ewe ratio >1 year	1:19

^a–d Means with different subscript letters across the rows are significantly different (P < 0.05), SE = standard error.

3.4. Sheep production objectives

The purpose of keeping sheep in the study area is presented in Table 4. In this finding, the primary reason for rearing sheep reported by the sheep owners was income generation, followed by saving large flocks of sheep. The income generated from the sale of sheep was spent on the purchase of food & clothes, farm investment, social activities and re-stocking. The primary purpose of rearing sheep in this study is in line with a study by Hizkel (2017) who reported that most farmers keep primarily as a source of income followed by saving purposes in the Bensa district, southern Ethiopia. Similar findings indicated that sheep are reared in many parts of the country mainly for income generation (Gebrekidan 2018).

Table 4. Purpose of keeping sheep (N = 50).

Parameters	1st	2^nd	3^rd	Index
Meat	0	7	32	0.16
Income	49	1	0	0.48
Manure	0	0	15	0.06
Saving	1	42	1	0.28
Social value	0	0	2	0.008

Index = sum of (3 for rank 1 + 2 for rank 2 + 1 for rank 3) for a particular trait by sum of (3 for rank 1 + 2 for rank 2 + 1 for rank 3) for all traits, N = number of households.

3.5. Major feed types, feeding and watering source

Sheep production constraints and the source of water for households engaged in sheep farming are presented in Table 5. Natural pasture was the common feed source, which includes road and fence side grazing and private or communal grazing, but the availability was varied across seasons. The result further indicated that crop residue was the main feed resource for undertaking sheep husbandry practices in the dry season, thus farmers allow the sheep to graze on the crop aftermath after the crop is harvested. This result is in line with the result of Jarso et al. (2023) that the main feed sources for small ruminant production are communal grazing land, crop residues and crop aftermath in the Arssi zone, Ethiopia. The result further indicated that during the cropping season, animals are usually tethered near the homestead under the supervision of the households’ family. Additionally, farmers provide enset leaves during the dry season and bole salt in the form of mineral supplement feeding accessed from surrounding areas. Based on the farmers’ information, during the wet and dry seasons, the major source of water is the river. Moreover, some farmers have used springs and ponds as a source of water for their sheep. Similar findings in line with this paper, Amare et al. (2019) for Begait sheep (Amhara) and Lakew et al. (2017) for local sheep in Wolaita (southern Ethiopia) reported that the major source of water for livestock is the river followed by community ponds and springs.

Table 5. Feed and feed utilization and water source for sheep production (N = 50).

Parameters	Dry season (%)	Wet season (%)
Feed source
Natural pasture/grazing land	93	82
Fed crop residue aftermath	89	–
Tethering	8	72
Enset leaves	56	23
Bole salt	34	32
Water source
River	76.8	94.6
Springs	10.4	3.2
Pond	12.8	2.2

Dash (-) means no available crop residues in the wet season.

3.6. Breeding practices

3.6.1. The mating system and source of breeding rams

The mating system and source of breeding rams are presented in Table 6. The majority of sheep owners in the study area use an uncontrolled mating system which is higher than the report of Teramaj (2020) (46.5%) in the highland of Wollo (north Ethiopia). The result was also similar to the report of Lakew et al. (2017) most of the sheep owners practised an uncontrolled mating system in the Wolaita zone of southern Ethiopia. This might be in rural areas where sheep graze and herd together throughout the year. The majority (67%) of farmers do not have their own breeding rams in their flocks and get their ewes from communal grazing area/neighbour rams; however, some farmers own homeborn rams, indicating that these flocks might be inbred within the same households. This might be due to a lack of knowledge about inbreeding and its impact on the productive and reproductive performance of sheep within the flock. A few farmers purchased breeding rams from their surrounding markets, thus safeguarding the flow of genes from diverse localities. The current result was inconsistent with those reported by Hailemariam et al. (2013) and Yadeta et al. (2016) majority of farmers use neighbour rams in Ethiopia.

Table 6. Mating system and source of breeding rams (N = 50).

Parameters	%
Mating system
Controlled	7.5
Uncontrolled	92.5
Source of Breeding rams
Born in the flock	29
Neighbour/Grazing land	67
Purchased from market	4

N = number of households.

3.6.2. Traits preference for the selection of breeding ewes and rams

Traditional selection of parents for the next generation from rams and ewes is very common and the selection criteria for male and female sheep are presented in Table 7. Accordingly, body conformation, large body size and twining ability were important trait preferences in breeding ewes given as 1st, 2^nd and 3^rd ranked by sheep owners. On the other hand, body size was the primary selection criterion followed by growth rate and coat colour for ram’s selection as parents to the next generation. These traits of interest from 1st to 3rd rated by sheep owners are essential for sheep productivity improvement objectives in the area. Farmers indicated that rams which grow at a faster rate and have large body sizes with red and white colour are the most preferred traits by the majority of farmers and have better market value than others. The current result is similar to Hailemariam et al. (2013), who reported that body size is the primary ram selection criteria in the Gamogofa zone (southern Ethiopia).

Table 7. Farmers’ trait preferences for selecting breeding ewes and rams (N = 50).

Farmers Traits preferences	1st	2nd	3rd	4th	5th	Index
Breeding ewe
Body size	13	24	6	1	0	0.24
Longevity	0	3	1	1	0	0.001
Body conformation	34	3	9	3	1	0.29
Lambing interval	0	0	0	2	10	0.019
Twining ability	3	12	29	2	1	0.21
Mothering ability	0	1	2	14	20	0.08
Coat Colour	0	8	2	26	2	0.09
Growth rate	0	0	2	2	6	0.024
Breeding ram
Body size	24	18	7	0	4	0.29
Body conformation	2	12	22	1	5	0.17
Growth rate	10	7	11	21	4	0.21
Libido	5	0	10	16	9	0.13
Pedigree	0	0	0	0	4	0.01
Coat colour	9	13	0	10	15	0.18
Twining ability	0	0	0	1	5	0.009

Index = the sum of (5 times first-order + 4 times second-order +3 times third-order + 2 times fourth-order + 1 times fifth-order) for individual variables divided by the sum of (5 times first-order + 4 times second-order +3 times third-order + 2 times fourth-order + 1 times fifth-order) for all variables, N = number of households.

3.7. Lamb growth performance

Lamb growth data of birth weight, weaning weights and six-month’s weight are presented in Table 8. The finding showed that the average birth weight of lambs was 3.01 kg (ranging from 2.3 to 3.6 kg). This wide range of variation might be attributed to the selection of breeding rams, husbandry and management practices. The birth weight of lambs found in this study was in line with the report of Ayele et al. (2015) as 3.1 ± 0.12 kg in Washera lambs (North Ethiopia), but it was higher than the value reported by Esubalew et al. (2018) as 2.8 ± 0.05 kg for Farta sheep and by Shigdaf et al. (2013) as 2.6 ± 0.01 kg in Washera lambs. Ayele et al. (2015) reported that birth weight was an indicator of the size of the lambs at the beginning of postnatal development and an important factor influencing later growth. The author also indicated that larger lambs at birth had greater capacity for growth and were more likely to be heavier at weaning. The result further indicated that lambs weaned at 90 days with heavier birth weights reached higher weights at six months. The current result of weaning and six-month weights of lambs was higher than those reported by Ashebir et al. (2019) at 7.95 ± 0.04 and 11.81 ± 0.21 for native sheep in the Fentale district (Oromia region), respectively.

Table 8. List square mean (mean ± SE) of the body weight of lambs at different ages.

Parameters	Minimum	Maximum	Mean
Birth weight (kg)	2.3	3.6	3.01 ± 0.3
Weaning weight (kg)	11.8	17.2	14.2 ± 0.9
Six-month weight (kg)	14.3	27.5	22.4 ± 1.1

SE = standard error, Kg = kilograms.

3.8. Factors affecting lamb growth performance

Effect of parity: the effect of parity consistently showed a significant effect for all weights except 180 days in the present study (Table 9). As observed from the result, lambs born at the 3rd and 4^th parity have higher (P < 0.01) birth weight and weaning weight as compared to those from the 1st, 2nd and 5th parities, but lower body weight was recorded at parity 1 and 2. The result of the effect of parity on growth traits of the current study is in line with the report of Digesa (2023) who reported that the lambs born from ewes in their earlier parity were consistently lighter than lambs born at later parities. This implies that lambs of lower parities at a lower body weight performance might be associated with the reproductive physiological process not being well developed in a younger dam when compared with an older one. Sodiq (2012) reported that parity and postpartum ewe’s body weight have significantly influenced weaning weight for dams with higher parity and heavier postpartum weight produce heavier lambs.

Table 9. Effect of fixed factors on lamb growth performance.

Factors	BWT	Weaning	Six months
Parity			NS
1	2.6 ± 0.04^b	11.1 ± 0.13c	21.6 ± 0.42
2	2.9 ± 0.06^b	13.2 ± 0.14 ^b	21.62 ± 0.43
3	3.3 ± 0.06^a	14.4 ± 0.14 ^a	22.3 ± 0.54
4	3.4 ± 0.07^a	14.1 ± 0.12^a	21.4 ± 0.43
5	2.61 ± 0.05 ^b	13.4 ± 0.12 ^b	22.1 ± 0.43
Birth type
Single	3.3 ± 0.07^a	14.8 ± 0.16 ^a	23.8 ± 0.18 ^a
Twin	2.8 ± 0.06^b	12.9 ± 0.15 ^b	21.5 ± 0.17 ^b
Sex
Male	3.1 ± 0.05^a	14.7 ± 0.14^a	23.7 ± 0.17^a
Female	2.91 ± 0.07^b	12.8 ± 0.18^b	20.3 ± 0.16^b
Season of birth
Dry season	2.6 ± 0.6^b	12.7 ± 0.07^b	20.6 ± 0.16^b
Wet season	3.4 ± 0.04^a	14.6 ± 0.06^a	23.5 ± 0.17^a

^a–c Means with different subscript letters across the rows are significantly different (P < 0.05), BWT = birth weight.

NS: not significant.

Effect of sex and litter size: The overall least-squares means and their standard errors of sex and litter size of lambs at birth, weaning and six months are presented in Table 9. As presented, the sex of the lamb was a significant source of variation at birth, at weaning (90 days), and at six months of lamb’s weight. The result showed that the birth to weaning and six-month weight was heavier in males compared to females. This result is in line with Abate et al. (2020) who reported that male lambs’ weight was heavier than female lambs for Bonga sheep. The growth performance of lamb was significantly (P < 0.05) affected by litter size (Table 9). This result is supported by Gemiyo et al. (2017) who reported that single birth type consistently has higher body weight than twin and triplet counterparts. Furthermore, Boujenane and Diallo (2017) reported that a single litter size type got a greater chance of achieving weaning weight than a twin litter size, in that there is no competition in the consumption of milk as per the lamb’s need. This could be due to lambs getting a large amount of milk from their dams and proper space during the foetus development.

Effect of the birth season: the effect of the season has consistently shown a significant effect on all lamb weight performance (Table 9). Thus, in both stages of growth performance, the highest weight was recorded in the wet season and the lowest weight was observed in the dry season. The lambs born in the wet season were superior by 0.8, 1.9 and 2.9 kg compared to lambs born in the dry season for weight at birth, weaning and six months of age, respectively. The effect of the season could be attributed to adequate forage available in the wet season which ensures the safe growth of the foetus. According to the report of Ashebir et al. (2019), lambs born in the wet season have a faster growth rate than in the dry seasons which might describe that seasonal variation in feed availability both in quality and quantity on natural pasture for the dam during lactation to produce and supply sufficient milk for their lambs. In contrast to this finding, the non-significant effect of season on lamb’s growth performance except for the birth season was reported by Belay and Haile (2009) in southwestern part of Ethiopia.

3.9. Reproduction performance of ewe

Age at first lambing (AFL): A total of 163 ewes were assessed during the animal section for their life histories of reproduction performance (Table 10). The AFL of this study was comparable with the study reported by Amare et al. (2021) (12.08 months) for Afar (Ethiopia) sheep. The AFL obtained in the current study is somewhat lower than Sisay et al. (2021) 11.69 months for Washera and 12.51 months for Gumze sheep. Age at first lambing obtained in this study was lower than the value reported by Memiru et al. (2012) 14.6 months for Bonga (southwest Ethiopia) sheep.

Table 10. Average reproduction performance of ewes.

Parameters	N	Average
Age at first lambing (months)	163	12.3 ± 0.12
Lambing interval (months)	245	7.8 ± 0.06
Fertility rate (%)	125	76.7

N: Number of animals.

Lambing Interval (LI): A total of 245 ewes were also assessed for their life histories of reproduction performance (Table 10). Lambing interval (LI) is the interval between two parturitions that determines reproductive efficiency in small ruminant production. The mean value for LI of this study was 7.8 ± 0.06 months. This LI in the current study was lower than the LI (262 ± 53.4 days) of sheep in the southwestern part of Ethiopia (Belay and Haile 2009) and slightly lower than the LI (261.14 days) of sheep in the Sidama zone (Shimelis 2012).

Fertility rate: The fertility rate of sheep (76.7%) observed in this study (Table 10) was higher than from the report of Deribe (2009) 54.04% was attributed to similar village management conditions of sheep and similar mixed crop-livestock sheep production.

3.10. Lamb survival, litter size and weaning rate

Survival rate: As presented in Table 11, the survival rate of the lambs was higher than that reported by Sisay et al. (2021) at 70.7% and 70.1% in Washera and Gumuz lambs survival rate, respectively. The survival rate of the current result is inconsistent with Lamesegn et al. (2018) at 89.6% in East Gojjam Ethiopia. Lamb birth weight, birth type, maternal nutrition, age of dams and sex affect lamb survival (Hatcher et al. 2009).

Table 11. Average survival, litter size and weaning rate of lambs.

Parameters	N	Average
Lamb survival (%)	189	86.2
Litter size (mean ± SE)	189	1.51 ± 0.1
Weaning rate (%)	102	81.6

N: Number of lambs; SE: standard error.

Litter size/prolificacy: Litter size is the combination of ovulation rate, embryo survival and number of lambs born per parturition. It is largely influenced by ovulation rate and determinants of ewe reproductive efficiency. The average litter size (1.51 ± 0.1) is shown in Table 11. Litter size in the current study was comparable with a previous report of Deribe (2009) i.e. 1.51 in Alaba district, Southern Ethiopia. However, the identified values were higher than the value reported by Hailemariam et al. (2013) i.e. 1.3 ± 0.04 local sheep in the Gamo Gofa zone. But, it was lower than the value reported by Yadeta et al. (2016) at 1.19 ± 0.42 local seep in Ada Bara and EJere (central Ethiopia).

Weaning rate: There is no definite time of weaning time at the farm level but, the weaning date in the current case was recorded on 90 days after birth (Table 11). Thus, the weaning rate, 81.6% in this study was higher than the findings of Ayele et al. (2015) that is, 79.78 + 0.54 in highland Ethiopia. Weaning weight is a trait of great economic importance in meat sheep production since it influences growth rate and survival (Taye et al. 2010). Lamb survival is directly associated with the environment and management conditions.

4. Conclusion

This study aimed to evaluate indigenous sheep’s productive and reproductive performance traits under farmers’ management conditions in Southern Ethiopia. The current result revealed that the average number of ewes per household was higher among the sheep flocks, but breeding rams were lower. The result of this research triangulated with the available literature on the subject matter, the growth performance of sheep in the study area is comparable with any other indigenous sheep breeds of Ethiopia. Birth weight, weaning weight and six-month weight and the interactions among lamb sex, birth type, dam parity and birth season are the most crucial sources of variation for sheep growth performance. As the result indicated lambs born at 3rd and 4th parity had higher birth weight and weaning weight than those found from the 1st, 2nd^, and 5th parities. Moreover, age at first lambing, lambing interval and litter size of sheep have appreciable reproductive performance traits. Lack of animal feed, disease problems, shortage of breeding rams and uncontrolled mating systems are the most important problems for sheep production in the study area. As policy direction, the authors suggested that integrated efforts combined with nutrition, health and participatory breeding programmes would help smallholder farmers in particular, and the country, in general, to exploit and conserve sheep genetic resources more efficiently and wisely in a sustainable manner.

Authors’ contribution

Debir L. Belay was involved in the conception of the research, design of the data collection tools, data collection, analysis and interpretation of the data and full write-up of the manuscript. Amelmal A. Abera contributed to the design of data collection, giving feedback for the data analysis and reviewing and giving comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Acknowledgements

The authors fully acknowledged, and gave appreciation for the financial support from the south Agricultural Research Institute (SARI). The authors give full appreciation for the integration and cooperation offered by experts working at the Livestock and Fishery Development Offices of the respective woreda throughout data collection.

Data availability statement

The authors declare that the data sets used for the analysis in this manuscript are fully available upon request from the corresponding author.

Additional information

Funding

This work was fully financed by Hawassa Agricultural Research Center (HARC), SARI.

Notes

1 Kebele is the local name for the lowest administration level in Ethiopia; it is synonymous with peasant association

2 Enset (Ensete ventricosum) is Ethiopian native and perennial root crop cultivated near homestead and is a major stable food source in southern Ethiopia.

3 Weaning rate =  (Number of lambs weaned/total number of ewes lambing) x 100%

4 Fertility rate =  (Number of females that gave birth/number of females mated) x 100%

5 Survival rate =  (number of living lambs at weaning/number of living lambs at birth) × 100

6 Liter size  = number of lambs at birth/number of ewes giving birth