elham rezvan nejad; abbas pakdel; seidreza miraey; hasan mehrbani yagane; mohammad mahdi yaghoobi
Abstract
Body Weight (BW) is a complex and important economic trait that may benefit from the implementation of Marker Assisted Selection (MAS). The objective followed in this study was to identify QTLs associated with BW at different ages as distinct traits based on an experimental half-sib cross of Japanese ...
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Body Weight (BW) is a complex and important economic trait that may benefit from the implementation of Marker Assisted Selection (MAS). The objective followed in this study was to identify QTLs associated with BW at different ages as distinct traits based on an experimental half-sib cross of Japanese quails divergently selected for BW at 4 weeks of age. The body weights at hatch, and as well at one, two, three and four weeks of age were assessed in the F2 population. A total 220 F2 individuals were genotyped for 6 informative microsatellite markers located on chromosomes 1, 2 and 9. The interval mapping was conducted to identify putative QTLs. A QTL for BW at hatch while another at 1 wk of age were identified as significant on chromosome 2 (P
s.m. hosseini vardanjani; seidreza miraey; a. pakdel; Hossein Moradi Shahrbabak
Abstract
To investigate the possibility of using ultrasound to estimate carcass composition, 38 Moghani male lambs were made use of. Subcutaneous fat depth (USFT) and longissimus dorsi muscle depth (ULMD) and area (ULMA) were assessed in the site between 12th and 13th ribs by using ultrasound equipped with an ...
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To investigate the possibility of using ultrasound to estimate carcass composition, 38 Moghani male lambs were made use of. Subcutaneous fat depth (USFT) and longissimus dorsi muscle depth (ULMD) and area (ULMA) were assessed in the site between 12th and 13th ribs by using ultrasound equipped with an 8 MHz probe. The lambs were then slaughtered. Carcasses were cold stored at 4°C for 24 hours and then the corresponding measurements performed on the carcasse. The right half of each carcass was dissected to determine carcass composition including muscle, fat and bone. The results revealed that correlation coefficients between the measurements of USFT, ULMD and ULMA and the corresponding carcass recordings were 0.51, 0.71 and 0.92, respectively. Also the correlation coefficients between ULMA and the levels of muscle and bone were recorded as 0.33 and 0.48, respectively. Coefficient of determination in simple regression equation to estimate the hot carcass weight, cold carcass weight, carcass weight without fat-tail and subcutaneous fat depth as based on body weight were 0.85, 0.87, 0.77 and 0.13, respectively. Multiple regression models while using USFT, ULMD, and ULMA in addition to body weight promoted the R2 to 0.86, 0.88, 0.83 and 0.53, respectively. Also the coefficient of determination in simple regression equation to estimate carcass longissimus dorsi muscle area employing only ULMA and carcass longissimus dorsi muscle depth with an employment of only ULMD were recorded 0.86 and 0.50, respectively. The results show that the use of ultrasound to estimate carcass composition on live sheep can be done successfully. Therefore important traits can be asessed and made use of in breeding programs without the need to slaughter killing the animal.
Mohamad Saheb Honar; Mohamad Moradi Shahr Babak; Seyed Reza Miraei Ashtiani; Mohamad Bagher Sayad Nezhad
Volume 41, Issue 2 , September 2010
Abstract
Genetic trend for production traits were estimated in Iranian Holstein cattle using the first lactation data recorded by Cattle Breeding and Dairy Product Improvement Center of the State from 1991 to 2006. Effect of some factors on genetic trend was investigated using data from 18 large herds. (Co) variance ...
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Genetic trend for production traits were estimated in Iranian Holstein cattle using the first lactation data recorded by Cattle Breeding and Dairy Product Improvement Center of the State from 1991 to 2006. Effect of some factors on genetic trend was investigated using data from 18 large herds. (Co) variance components and genetic parameters were estimated, using five trait animal model and EM-AI algorithm in WOMBAT software. Estimated heritability for milk, fat, protein yields, fat percent and protein percent were 0.255, 0.197, 0.210, 0.317 and 0.308, respectively. Linear regression of Estimated Breeding Values (EBV) on birth year was used to estimate genetic trend. Estimated genetic trend for the animals for milk, fat and protein yield were 35.437±2.655, 0.714±0.059, 0.945±0.069 kg and for fat and protein percent were -0.006±0.0005 and -0.002±0.0002, (P
