Review of Reproductive Performance and Selection Criteria of Goats

Zemedkun Diffe and Tesfa Kassa

Department of Animal Sciences, Mekdela Amba University, Tulu Awulia, Ethiopia

ABSTRACT

Goats are small ruminants that have a vital role in the livelihood of the Ethiopian community. Their prolificacy and fecundity, short generation interval, adaptation to harsh environments, and their ability to thrive under limited feed resources, all make them favorable as an investment and insurance. Reproductive performance is one of the most important economic traits in terms of goat production. Reproductive performance determines several aspects of goat production and their reproduction and is thus important for flock expansion and replacement. The reproduction efficiency of an animal helps in evaluating the strength and weaknesses of the genotypes across different production environments. Therefore, optimum reproductive efficiencies in the flock are fundamental to the success of any production system. The trait influences the overall productivity of the flock. Reproduction failure is the first indicator of the low profitability of the flock. The reproductive efficiency of goats is an accumulation of several correlated traits. The reproductive traits of goats are age at puberty, age at first kidding, post-partum heat period, kidding interval, litter size, parity order, and service per conception. In Ethiopian communities the phenotypes of the goats have an important influence on socio-cultural and economic values; as a result, most farmers pay special attention to the shape of the horn, presence/absence of wattles, color of the eyes, shape of the udder, coat colors and body sizes.

Keywords: Reproductive Performance, Goat Selection Criteria, Ethiopia

Introduction

Small ruminants (sheep and goats) are an integral part of the livestock sub-sector in Ethiopia (Zewdie and Welday, 2015). They constitute around 33.14 %of the total livestock population of the country (CSA, 2018). They are an avital part of the livelihood systems among the agrarian and pastoral communities by contributing to the socio-economic wellbeing of their rearers (Markos, 2006; Tsigabu, 2015). Their prolificacy and fecundity, short generation interval, adaptation to the harsh environment, and their ability to thrive under limited feed resources, all make them favorable as an investment and insurance (Tsedeke, 2007). Small ruminants also serve as sources of foreign currency and are exported in large numbers to the neighboring countries (Berhanu et al., 2006). It has also been reported in a study by Zelalem and Fletcher (1993) that, small ruminants serve as a source of wealth for the resource-challenged members of the society who are unable to invest in large ruminants. The reproductive performances of small ruminants are important factors influencing flock productivity (Marian, 2009). The reproductive efficiency of goats is an accumulation of several correlated traits. According to Rume et al., (2011), the reproductive traits of goats are age at puberty, age at first kidding, post-partum heat period, kidding interval, litter size, parity order, and service per conception. In Ethiopian communities the phenotypes of the goats have an important influence on socio-cultural and economic values; as a result, most farmers pay special attention to the shape of the horn, presence/absence of wattles, color of the eyes, shape of the udder, coat colors and body sizes (Zewdei and Welday, 2015).

Reproductive Performance of Goats

The reproductive performances of small ruminants are important factors influencing flock productivity (Marian, 2009). All forms of output including milk, meat, and skin depend on these factors. The factors vary both between breeds and even within flocks in a given population (ILCA, 1990). Considering reproductive parameters in the selection and crossbreeding programs will directly influence the efficiency of milk and meat production and the rate of genetic progress (Mukasa-Mugerwa and Azage, 1991), and the size of the replacement stock. These factors are influenced by several factors viz. genotype, nutrition, diseases, and other management practices (Kidus, 2010).

The reproductive efficiency of goats is the accumulation of several correlated traits. According to Rume et al., (2011), the reproductive traits of goats are age at puberty, age at first kidding, post-partum heat period, kidding interval, litter size, parity order, and service per conception. Similarly, a study by Song et al., (2006) indicated that the reproductive efficiency of goats is determined by age of goats at first kidding, kidding interval, and birth type (litter size). Information regarding reproductive performance is very important to undertaking any breed improvement work in a particular area. The trait varies both across the different goat breeds and among goats of a particular breed (Ibrahim, 1998).

Age at puberty and sexual maturity

Puberty is the stage of sexual development at which the goats become capable of breeding (first ovulation in the female and first spermatozoa in the ejaculate of the male), however, this may or may not correlate with their maturity (Kanbhar et al., 2016). In both the males and does, puberty may be often reached without adequate physical growth to support reproduction, and in the does, the first ovulation may not necessarily coincide with the first estrus (Girma, 2008). The age at puberty of some goat breeds were presented in Table 1 below. The observed variations of puberty age are due to the influences of factors like nutrition, body weight, breed, season of birth, and growth rate (Girma, 2008).

Table 1: Age at puberty and sexual maturity of some goat breeds

Breed		AP	Age at sexual maturity	References
Tropical goats	Male	97 days	132 days	Payne and Wilson (1999)
Tropical goats	Female	na	120-180 days	Payne and Wilson (1999)
Ethiopian indigenous goats		7-15 months	Na	Solomon et al., (2014)
Ethiopian indigenous goats		7.4 months	Na	Girma (2008)
Arsi bale	Male	7.6 months	Na	Belete et al., (2013)
Arsi bale	Female	7.9 months	Na	Belete et al., (2013)
Horo Breed	Male	na	9.8 months	Ahmed et al., (2015)
Horo Breed	Female	na	7.11 months	Ahmed et al., (2015)

AP= Age at puberty, na= not available

Table 2: Age at first kidding of some goat breeds

Breed/ecotype	Age at first kidding	References
Indigenous Ethiopian goats	12-20 months	Solomon et al., (2014)
Indigenous Ethiopian goats	12-24 months	Girma (2008)
Arsi Bale	437.1 -445.5 days	Tesfaye (2009)
Southern Ethiopia goats	358.5 days	Deribe (2009)
Keffa	12.9 months	Belete (2009)

Age at first kidding

Age at first kidding is the age at which does particulate for the first time (Girma, 2008; Rume et al., 2011; Hulunim, 2014). It is a function of puberty, age at first breeding and conception, and successful completeness of pregnancy (Kumbhar et al., 2016). Age at first kidding varies both across breeds and management within breed (Girma, 2008). Age at first kidding is an indication of the overall flock productivity (Tesfaye, 2009). The lifetime production can be increased by decreasing the first kidding age. A wide range of 375 to 854 days of age at first kidding was reported in different management and breeds of Ethiopian goats which are influenced by genotype, management, season, and type of birth (Kebede et al., 2012)

Kidding interval and litter size

The kidding interval refers to the number of days between successive parturitions (Alexandre et al., 1999; Rume et al., 2011). It is an important predictor of lifetime productivity (Awemu et al., 1999). The prolonged kidding interval is responsible for a decrease in the productivity of goats (Awemu et al., 1999). Litter size means the number of kids born per doe per kidding (Akpa et al.,2011). Findings of a study by Solomon et al., (2014) indicated that the average litter size of goats raised on station and on-farm conditions ranged from 1 to 1.7. The litter size is largely influenced by the ovulation rate. The ovulation rate is correlated to the type of breed and improvement could be achieved through selection (Ibrahim, 1998).

Table 3: Kidding interval and litter size of some goat breeds

Breed	Kidding interval	References
Tropical goat	2 years	Rume et al. (2011)
Ethiopian goats	8 months/245 days	Girma (2008)
Ethiopian goats	6 - 8 months	Solomon et al., (2014)
Arsi Bale	8 months	Belete et al., (2015)
Breed	Liter size	References
Nigerian goats	1-4 (Mean 1.7)	Akpa et al., (2011)
Ethiopian goats	1.06 - 1.75	Solomon et al., (2014)
Arsi Bale	1.33	Belete et al., (2015)
Arsi Bale	1.6	Hailu et al., (2008)
	1.77	Ahmed et al., (2015)

Selection Criteria of Goats

In Ethiopian communities the phenotypes of the goats have an important influence on socio-cultural and economic values; as a result, most farmers pay special attention to the shape of the horn, presence/absence of wattles, color of the eyes, shape of the udder, coat colors and body sizes (Zewdei and Welday, 2015).

According to the study by Tegegn and Askale (2017), most of the farmers in the southwestern part of Ethiopia give more attention to the selection of breeding rather than that of the bucks. However, studies by Maria (2009) have indicated that “Bucks” are half the flock, and the selection of a good buck ensures the above-average productivity of the flock. Bucks with large and good conformation (tall, upright standing, strait back profile etc) usually have higher productivity (Misbah, 2015). The preference for body size might be because larger animals, in particular, get better market prices, had better growth rates, and reached market weight sooner and such animals can walk long distances (Netsanet et al., 2016).

The effectiveness of any selection program depends on the heritability of the trait (Yaekob et al., 2015). According to Girum et al., (2013), the pastoralists in Ethiopia generally select their breeding flock based on the body condition, growth, pedigree, and lacteal characteristics.

Findings of a study by Seifemichael et al., (2013) showed that the morphological/skeletal traits are highly heritable and therefore selections based on these traits are mostly successful. However, most of the reproduction and production traits viz. age at first mating, conception rate, milk yield, etc. are mostly moderately to lowly heritable; therefore, these traits are mostly improved through improved proper husbandry practices. Findings of a study by Ahmed et al. (2015) indicated that in the western part of Ethiopia breeding does are selected based on their litter size followed by their growth rate and age at first kidding.

The traits selected by the goat rearers in the midlands are their prolificacy, body conformation, survivability of the kids, and coat colors. The does are selected based on their good mothering ability, short kidding interval, longevity, and early maturity (Tegegn and Askale, 2017).

Goat rearers in the highlands select the does base on their body conformation, adaptation to cold climate, coat color (long hair and black) survival of the kids, good mothering character, prolificacy, short kidding interval, and low age at first maturity, besides the longevity of the doe themselves (Yaekob et al.,2015). Black-coated goats, however, are believed to have superior adaptation to seasonal cold weather or cold nights as the dark pigment helps them to warm-up earlier than goats with other coat colors (Robertshaw, 2006). On contrary to the same, the breeding bucks are selected based on their higher growth rate, and appearance besides their coat color (Belete et al., 2015).

Furthermore, findings of a study by Yaekob et al. (2015) indicated that in all agroecology the traits which were similar in selecting the does were body conformation, adaptation, coat color, early maturity, and prolificacy. The bucks were however selected based on their pedigree, and own performance besides other criteria of traditional systems (Girum et al., 2013).

CONCLUSION

The reproductive efficiency of goats is an accumulation of several correlated traits. The reproductive traits of goats are age at puberty, age at first kidding, post-partum heat period, kidding interval, litter size, parity order, and service per conception. The better reproductive performance of the goat determines its productivity and the economic significance of the goat breeds. Selection is the prerequisite to replacing stocks by considering their own morphological and production characteristics. Bucks are selected based on physical appearance while females have based on a reproductive trait-like age at first puberty, litter size, kid growth, and kidding interval. This review

CONFLICT OF INTERESTS

The author declares that there is no conflict of interest.

REFERENCES

Ahmed S, Kefelegne K and Kefena E (2015) Breeding objective, selection criteria and breeding practice of indigenous goats in western Ethiopia: implications for sustainable genetic improvement. Greener Journal of Agricultural Sciences.5; pp.167-176.

Akpa, G. N., C. Alphonsus, S. Y. Dalha, H. Yakubu and Garba (2011) Relationship between litter size and parity of doe in smallholder goat herds in Kano and its environs, Nigeria. African Journal of Agricultural Research.6(29): pp.6212-6216

Awemu E.M., Nwakalor L.N., and Abubakar B.Y (1999) Environmental influence on per weaning mortality and reproductive performance on Red Sokoto does. Small Rumin.Res. 34; pp.155-160.

Belete A, Kefelegn K and Kefena E (2015) Breeding objectives, selection criteria and breeding system of indigenous goat types in Bale zone, Oromia, Ethiopia .Int. J. Agril. Res. Innov. & Tech. 5 (2): 7-15, December,

Belete S (2009) Production and marketing systems of small ruminants in Goma district of Jimma zone, western Ethiopia. Msc. Thesis, Hawassa University, April,2009, Awassa, Ethiopia. pp. 38-54.

Berhanu G, Hoekstra D and Azage T (2006) Improving the competitiveness of agricultural input markets in Ethiopia: Experiences since 1991. Paper Presented at the Symposium on Seed-Fertilizer Technology, Cereal Productivity and Pro-Poor Growth in Africa: Time for New Thinking 26th Triennial Conference of the International Association of Agricultural Economics (IAAE), August 12-18, 2006, Gold Coast, Australia.

Central Statistics Agency (2018) Federal democratic republic of Ethiopia central statistical agency agricultural sample survey 2017/18 report on livestock and livestock characteristics (private peasant holdings) V2, Addis Ababa,Ethiopia.Volume, 2; 94pp.

Deribe G (2009) Ethiopian-farm performance evaluation of indigenous sheep and goats in Alaba, Southern Ethiopia.MSc thesis. Awassa, Ethiopia: Hawassa University.pp163

Girma A (2008) Reproduction in sheep and goats. Alemu Yami and R.C. MERKEL (Eds.). IN: Sheep And Goat Production Hand Book For Ethiopia. Ethiopia Sheep And Goats Productivity Improvement Program (Esgpip), Addis Ababa, Ethiopia. Pp. 57-72.

Girum G, Aynalem H and Taddele D (2013) Breeding scheme based on community-based participatory analysis of local breeding practices, objectives and constraints for goats around Dire Dawa, Ethiopia. livest.Res.Rural Dev.,Vol.25.

Hailu D, Gemeda D, Berhanu S, Takele F, Mesfin T, Tatek W and Tesfaye A (2008) Non-genetic factors influencing post-weaning growth and reproductive performances of Arsi-Bale goats.Livestock Research for Rural Development 20 (7) .

Ibrahim H (1998) Small Ruminant Productions Techniques. ILRI training manual. ILRI (International Livestock Research Institute), Nairobi, Kenya. 192p.

Kidus N (2010) Goat Breeds Utilization and Productivity of Cross breed Goats in Eastern and Southern Ethiopia and Biophysical Model. MscThesis.Submitted to Graduate School of Addis Ababa University.

Kunbhar H K, Memon A. A., Bhutto A. L., Zahid Iqbal Rajput, V. Suthar, Azizullah Memon and R. A. Leghari (2016) Study on female reproductive performance of Kamohri goat managed under traditional management conditions in district Hyderabad, Sindh, Pakistan. Int. J. Adv. Res. Biol. Sci. 3(3);p251-260.

Markos T (2006) Productivity and Health of indigenous sheep Breeds and Crossbreds in the Central Ethiopian Highlands.Faculty of Medicine and Animal Science department of Animal Breeding and Genetics.Ph.D.dissertation. Swedish University of Agricultural.

Payne W. J.A and Wilson R.T (1999) An introduction to Animal Husbandry in the tropics. Blackwell Publishing Company. Oxford, UK. 451- 470.

Robertshaw D (2006) Mechanisms for the control of respiratory evapo- rative heat loss in panting animals. J. Appl. Physiol. 101: pp664-668

Rume, Chowdhury F.I. A. K, Islam M.S., and Karim M.R (2011) Study on the Productive and Reproductive Characteristics of Goats in the Selected Coastal Regions of Bangladesh. Bangladesh Res. Publications J. 5(3): pp2014-2020

Seifemichael M, Kefelegn K and Negassi A (2013) Phenotypic Characterization of Indigenous Afar Goat Breed and Husbandry Practices of Pastoralists in Afar Region.

Solomon A, Mwai O, Grum G, Aynalem H, Rischkowsky B, Solomon G and Tadelle D (2014) Review of goat research and development projects in Ethiopia. ILRI project report. Nairobi, Kenya: Inter- national Livestock Research Institute

Song H.B, Jo I.H and Sol H.S (2006) Reproductive performance of Korean native goats under natural and intensive conditions.Small Rumin. Res. 65:284-287

Tegegn F and Askale G (2017) Goat production system and breeding practices in pastoral and mixed crop livestock production system in south western part of Ethiopia. Agriculture And Biology Journal Of North America ISSN Print: 2151-7517.

Tesfaye T (2009) Characterization of goat production systems and on- farm evaluation of the growth performance of grazing goats supplemented with different protein Sources in Metema Woreda, Amhara Region, Ethiopia. An MSC thesis submitted to the school of graduate studies. Haramaya University,Haramaya

Tsedeke K (2007) Production and marketing of sheep and goats in Alaba, SNNPR.Msc thesis Hawassa University. Hawassa, Ethiopia.

Tsigabu G (2015) Phenotypic characterization of goat type and their husbandry practices in Nuer zone of Rambella people regional state, southwestern Ethiopia. A thesis submitted to the school of animal and range sciences, school of graduate studies Haramaya University.

Yaekob L, Kirman M. A and Birhanu B (2015) Morphological Characterization of Indigenous Woyto Guji goat type in Loma district, Southern Ethiopia. African Journal of Agricultural Research. Vol. 10(20), pp. 2141-2151.

Zelalem A and Fletcher I C (1993) Small ruminant productivity in the central Ethiopia mixed farming systems. In Proceedings of the fourth National Livestock Improvement Conference. Addis Ababa, Ethiopia,13-15 Nov. 1991. IAR, Addis Ababa.pp.141-147

Zewdie B and Welday K (2015) Reproductive Performance and Breeding Strategies for Genetic Improvement of Goat in Ethiopia: A Review. Greener Journal of Agricultural Sciences. Vol. 5 (1), pp. 023-033.