Maryam Karami; Karim Hasanpur; Jamal Fayazi; Arash Javanmard; Hamid Varnaseri
Volume 23, Issue 4 , January 2022, , Pages 501-514
Abstract
The aim of present study was to investigate the effect of selection against ascites syndrome on different traits body growth, internal organs, and blood parameters in a broiler line. Therefore, by classifying different families based on the frequency of ascites under intense ascites inducing condition ...
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The aim of present study was to investigate the effect of selection against ascites syndrome on different traits body growth, internal organs, and blood parameters in a broiler line. Therefore, by classifying different families based on the frequency of ascites under intense ascites inducing condition (AIC), 10 susceptible families (SUS) and 10 resistant families (RES) to ascites were selected and another set of offspring from the same families were bred under normal commercial condition (NCC). This process of selection and cross validation was carried out twice in the two distinct generations. The genetic relationship of different traits, the difference in the frequency of ascites between AIC and NCC, and the difference between different traits in SUS and RES were performed by correlation statistics, Chi-square test, and GLM procedure of SAS software (version 9.1), respectively. The correlation between ascites susceptibility in different families indicated that families that showed more ascites under AIC also had more ascites under NCC. Comparative study of different traits in susceptible and resistant groups showed that in SUS, body weight, growth rate and respiratory capacity were significantly lower and blood partial pressure of carbon dioxide was significantly higher than RES (P<0.05). In the present study it was shown that selection against this syndrome not only does not reduce growth rate in the investigated broiler line, but also improves growth traits and resistance to this syndrome in the mentioned line.
karim hasanpur; Ali Asghar Aslaminejad; Mohammad Moradi Shahrbabak
Volume 14, Issue 1 , September 2012, , Pages 19-31
Abstract
The effects of days in milk (DIM) on the curves of milk yield and milk fat percentage in Holstein cows of Iran were studied. A total of 964,606 and 885,346 test day records were used for milk yield and milk fat percentage, respectively. The data were grouped in four classes including: 1) 240 < DIM ...
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The effects of days in milk (DIM) on the curves of milk yield and milk fat percentage in Holstein cows of Iran were studied. A total of 964,606 and 885,346 test day records were used for milk yield and milk fat percentage, respectively. The data were grouped in four classes including: 1) 240 < DIM < 301, 2) 300 < DIM < 401, 3) 400 < DIM < 501 and 4) 500 < DIM < 601 days. To fit the curves, nine non-linear models for every one of the classes were applied. The Narushin & Takma 1 function which previously has been used for fitting the production and growth characteristics of chickens was used in this study. It showed a relatively high goodness of fit in fitting milk yield and milk fat percentage curves compared to other functions. Wood, Dijkstra and Rook functions showed higher Adjusted R2 whereas the third order Legendre polynomial function showed the lowest value in all the classes. The cows had longer lactation period, showed higher persistency and yielded higher daily milk at peak and post peak stages of lactation period. The forth class of cows yielded considerably higher milk and fat (based on 305 day production) compared to other groups. On the contrary, the rate of reduction of milk yield was significantly high for cows located in the lowest lactation length class and the slope of declining stage of milk yield curve was sharper.