ABSTRACT

Offspring yield in farm animals is an important criterion that determines the sustainability (existence) of a breed, the profitability of the enterprise and the efficiency of breeding activities. The share of genetic influence on this critical yield is low (0.05-0.20), but the share of environmental factors is high. The number of offspring a female gives birth to in a litter varies depending on the species. In small ruminants, which show high adaptability in all climates in the world, have a large raising area, are a source of animal food and economic income in rural life, and contribute to the economy of countries, the efficiency of offspring production gains even more importance with the prominence of meat yield. The formation of an offspring involves a long process, from forming gamete cells to birth. The effective number of offspring (marketable or weaning) produced by a female in a year varies depending on the litter's size, the offspring's viability, and the parturition interval. The litter is shaped according to the care-feeding during the mating period, the breed, the age of the mother, the body weight of the mother, the mating season, the care-feeding in the embryonic period, the ambient temperature in the embryonic period, the lambing interval, the length of the mating season. Life in the prenatal (prenatal) stages of fertilization, implantation (embryo), and the fetus depend on the genetic nature and the environment provided by the mother. In the prenatal period, the breeder's intervention in the environment provided by the mother to the offspring is limited and indirect. The life immediately before or just after birth (perinatal, neonatal) and postnatal (postnatal) period depends on the genetic structure of the offspring and the environment presented to the offspring. During these periods, the breeder has more opportunity to regulate the factors related to its offspring's environment. In evaluating offspring productivity, the economic return of the offspring is an important criterion. For this reason, the economic return of the offspring to the business is more important than how many offspring an animal gives birth to. In small ruminant breeding, offspring yield criteria are used to evaluate the number of offspring at birth per female with offspring potential, the number of offspring obtained per female that gives birth, ovary efficiency, and parturition interval, and gives essential clues in terms of fertility performance for a female. However, only offspring at weaning or incomes from their selling could be contributed to the business economy, herd substitution, and breeding efforts. The offspring not brought into the economy causes the female to leave the herd earlier, increases the herd replacement costs, and decreases the operating income. In small ruminant breeding, offspring production efficiency and farm profitability can be increased with improvements made by the raiser in the factors affecting prenatal (embryo losses, abortions) and postnatal offspring survivability and development. Based on the literature, the practices that the breeder should do to increase the efficiency of offspring production in sheep and goat breeding will be examined in this study.

Key Words: Lamb, Kid, Goat, Sheep, Offspring Yield, Mortality Rate, Embryo, Management