Authors: MEHMET EMİN TEKİN, MEHMET GÜRKAN, OSMAN KARABULUT, HÜSEYİN DÜZGÜN
Abstract: This study was conducted to investigate the pre-weaning growth of crossbreed types. Fifteen genotypes (F_1 and B_1) were obtained by crossbreeding in the Animal Research Institute in Konya from 1989 to 1996. These 15 genotypes were classified in 4 appropriate genotype names: Hasmer, Hasak, Hasiv and Linmer. GLM and Tukey's HSD tests were used for statistical analyses. Year, genotype, sex, birth type, and dam's age were introduced into the model as fixed factors and birth weight was introduced as a covariate along with year x genotype interaction. While the effects of year, dam's age, birth type, and sex on birth weight were significant, the effects of genotype and year x genotype interaction were insignificant. The overall birth weight means were 4.29, 4.00 and 3.99 kg (P < 0.001) for 1997, 1998 and 1999, respectively. The differences between the genotypes were not significant, and the values were 3.95-4.19 kg for all genotypes during the 3-year experimental period. The birth weights of lambs from dams aged 3 years or older were higher than those of lambs with 2-year-old dams. The birth weights of ram lambs were higher than those ewe lambs, and single born lambs had higher birth weights than did twin born ones. The lambs were weaned at the age of 75 days. All factors except for dam's age and birth type affected the weaning weight. The weights of lambs at 75 days were 17.5-19.8 kg in 1997, 17.0-20.1 kg in 1998, and 19.5-22.5 kg in 1999, and the differences between genotypes were significant in all 3 years, although the superiority of some genotypes over others varied year by year. The year of weaning weights were significant in all genotypes expect for Hasiv, and the values obtained in 1999 were higher than those from 1997 and 1998. The same results were obtained in daily gains in the suckling period. The daily gains were 176-207 g in 1997, 170-212 g in 1998 and 203-243 g in 1999, and the values for 1999 were higher than those for the 2 previous years. The daily gains were 239, 231, 210, 203, 218, 241 and 243 g for the Hasmer, Hasak, Hasiv, Linmer, Merino, Akkaraman and Awassi breeds, respectively, in 1999 and the values for Hasiv and Linmer were lower than those for the other crossbreed types and the Akkaraman and Awassi breeds. In conclusion, the superiority of 1999 to 1998 and 1997 in terms of growth traits was observed not only in crossbred but also in purebred animals, and this may not be the result of selection but rather of an improvement in environmental factors. In general, the Linmer type exhibited a lower performance.
Keywords: Mutton sheep breed, crossbreeding, selection, new sheep types, growth
Full Text: PDF