Performance traits of purebred Ossimi and Rahmani lambs and their crosses with Finnsheep born under two accelerated mating systems

Abstract

Abstract. The aim of the study was to carry out crossing of the local breeds with a known prolific breed with the hope to be a beginning to develop improved synthetic lines under the sub-tropical conditions. In the present study, the data represented 4 genotypes: 2 pure Egyptian local fat-tailed breeds [Ossimi (O) and Rahmani (R)], one back-cross [1/4 Finnish Landrace (F) 3/4 O] and one 3-breed-cross [1/4 F 1/4 O 1/2 R]. The lambs resulted from two accelerated systems: 3 lambings/2 years and 2 lambings/1 year. The results showed that in 3 lambings/2 years and 2 lambings/1 year systems, the crossbred lambs were significantly (P<0.01 or 0.05) higher in most of the growth traits, carcass characteristics and weight of ewe lambs at first mating, and were significantly (P<0.01) lower in percentages of the tail and bone and age of ewe lambs at first mating than in their maternal (local) breeds. Spring born lambs were significantly (P<0.01 or 0.05) higher than those born in the other seasons of the year in body weights at 16 and 24 weeks of age and daily gain weight during 0–<8 weeks in 3 lambings/2 years system, and in daily gain weight during the period 8–<16 weeks of age in 2 lambings/1 year system. When using some indices based on combining a number of economic traits of the study (including slaughter weight, feed efficiency, dressing percentage, percentage of lean in the carcass, conception rate, lambing rate and average litter size) to compare the crossbreds with the local ones, the obtained values were not in favour of the crossbreds, which may throw some shadows on feasibility of applying crossing of the Egyptian local sheep with the Finnsheep. Comparison between the two mating systems showed that the 3 matings/2 years surpassed the 2 matings/1 year system in all the indices developed. When calculating the productive efficiency per one year by combining the traits: survivals ratio – that equals: 1 − (mortality rate at 8 weeks) – and frequency of lambing per one year, the values were 15.0 and 13.2 % in the two systems, respectively, confirming the previous results.

Evaluation of Growth Performance, Blood Metabolites and Gene Expression Analysis in Egyptian Sheep Breeds, in Relation to Age

“…Present results indicated that Ossimi sheep have the largest value of live body weight (45.25 ± 1.98 Kg) at the third age category, and there weren't any significant differences between Rahmani and Barki breeds. The results of this study are in harmony with those previously reported by Almahdy et al (2000), Marai et al (2009), Khalifa et al (2013), Hassan (2017) and El-Malky et al (2019). They mentioned that the average live body weights were ranged from (51-53 kg) adult weight for the Ossimi and Rahmani breeds, and (44 kg) for the Barki breed.…”

“…Another agreement obtained by Khalifa et al (2013) they found a positive effect of advanced age for Rahmani males live body weight. Furthermore, Marai et al (2009) and El-Malky et al (2019) reported that breed had a significant (P<0.01) effect on live body weight as Ossimi breed showed heavier weight than Rahmani and Barki breed.Another point of view reported by El-Tarabany et al (2017) they mentioned that there was no difference in live body weight between Ossimi and Rahmani breeds; however, Rahmani breed had a higher body weight compared to Ossimi breed. Body length differs according to many factors such as breed, gender, yield type, and age.…”

BMPR-1B, BMP-15 and GDF-9 genes structure and their relationship with litter size in six sheep breeds reared in Egypt

“…According to the results of nucleotide sequencing for GDF-9 gene and SSCP technique for BMP-15 gene, Rahmani breed and its cross with Barki carried the mutations Fec-G H of GDF-9 and Fec-X G of BMP-15 genes. Additionally, the replacement of amino acids for GDF9 may enhance the high rate of twinning [18,26]. This theory agrees with our results on the twinning rate in Rahmani and its cross with Barki compared to other breeds.…”

Comparative tail fat transcriptome analysis of key genes and pathways activated in response to fat deposition in two sheep breeds with extreme fat-tail phenotype differences

“…Thus, the e ciency of meat production is higher than that of fat in intensive and semi-intensive sheep industry systems, and the tail fat of Altay sheep (comprising up to ~ 25% of carcass weight) markedly lowers their economic value [8]. For the above reasons, fat-tailed sheep breeds have been gradually rejected by producers and consumers, and leaner sheep breeds are more desirable [9][10][11][12][13][14]. Therefore, elucidation of the key genes that regulate the deposition and decomposition of tail fat in sheep and the molecular mechanisms controlling fat metabolism should greatly accelerate the breeding course of lean sheep and production of more healthy mutton for consumption.…”