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A Genetic Study on Lifetime Traits for Experimental Herds of Friesian Cattle 全文
2024
Abd El-Rahman, Faten | Elsayed, Manal | El-Saied, Usama | Ashmawy, Abdelhaleem | Mansour, Hussein
This study analyzed data from 5,518 lactations involving 1,749 Friesian cows raised in two experimental herds between 1992 and 2022. The study aim was to estimate the genetic parameters for longevity traits using a multiple-trait animal model, including age at first calving (AFC), lifetime (LT), lifetime days in milk (LTDIM), total lactations (TL) and lifetime milk yield (LTMY). On average, cows lived for 80.4 months, with 41% of their lifetime spent in milk production. They averaged 3.2 lactations, starting at 32.7 months. Heritability estimates for longevity traits were 0.09 to 0.12 suggesting limited direct selection potential. Strong genetic and phenotypic correlations (0.88–0.96) were observed between lifespan traits and total milk production. Similar correlations were found between partial lifetime milk yield traits for the first three lactations and total lifetime milk yield (0.44 to 0.97). Genetic correlations between lifetime traits were consistently high (0.88 to 0.99), mirroring phenotypic correlations. Notably, heritability estimates for partial performance traits increased with more lactations considered, and correlations between partial and lifetime traits were improved with additional data. These findings suggest the feasibility of early indirect selection for longevity through correlated responses in early performance traits, particularly early lactation milk production, to enhance overall lifetime productivity.
显示更多 [+] 显示较少 [-]A Genetic Study on Lifetime Traits for Experimental Herds of Friesian Cattle 全文
2024
Faten Abd El-Rahman | Manal Elsayed | Usama El-Saied | Abdelhaleem Ashmawy | Hussein Mansour
This study analyzed data from 5,518 lactations involving 1,749 Friesian cows raised in two experimental herds between 1992 and 2022. The study aim was to estimate the genetic parameters for longevity traits using a multiple-trait animal model, including age at first calving (AFC), lifetime (LT), lifetime days in milk (LTDIM), total lactations (TL) and lifetime milk yield (LTMY). On average, cows lived for 80.4 months, with 41% of their lifetime spent in milk production. They averaged 3.2 lactations, starting at 32.7 months. Heritability estimates for longevity traits were 0.09 to 0.12 suggesting limited direct selection potential. Strong genetic and phenotypic correlations (0.88–0.96) were observed between lifespan traits and total milk production. Similar correlations were found between partial lifetime milk yield traits for the first three lactations and total lifetime milk yield (0.44 to 0.97). Genetic correlations between lifetime traits were consistently high (0.88 to 0.99), mirroring phenotypic correlations. Notably, heritability estimates for partial performance traits increased with more lactations considered, and correlations between partial and lifetime traits were improved with additional data. These findings suggest the feasibility of early indirect selection for longevity through correlated responses in early performance traits, particularly early lactation milk production, to enhance overall lifetime productivity.
显示更多 [+] 显示较少 [-]Study of genetic relationship between some olive varieties in gellin gene bank
2011
Moustaf, N. | Hamed, F. | Lawand, S.
Olive tree (Olea europaea L.) is one of the most important fruit trees, there is a lot of varieties with the possibility of mislabeling, homogenouses and synonyms, which makes major troubles when having plant material for propagation and breeding programs. In this search, 12 olive varieties (Maw! Istanbul!, Khilkhali Khishen, Dan, Mniekri, Adkam, Doaibli, Mot, Khilkhali Saghir, Karamani Modabal, Mawi abo Shokeh, Sourani, and Abo Shokeh), cultivated in ACSAD Gene bank in Gellin, were characterized by ISSR molecular markers to determine the relationship between these varieties. Depending on quantitive traits the results indicated that these varieties are so close to each other's, ranged from 60% and 85%. It was noticed that Mneikri was apart from the other varieties in its traits, (polymorphic rate was 92.94%).
显示更多 [+] 显示较少 [-]Molecular markers for salt tolerance in some inbreds of maize, Zea mays L.
1997
Abd-El-Tawab, F.M. | Fahmy, E.M. | Bahieldin, A. | Eissa, H.F. (Ain-Shams Univ., Cairo (Egypt). Faculty of Agriculture)