جستجوی مقالات مرتبط با کلیدواژه « صفات تولیدی » در نشریات گروه « علوم پایه »

The most appropriate way to maximize profitability through breeding is to use economic coefficients of traits along with genetic evaluation. The purpose of this study was to estimate the economic coefficients of production, reproductive, performance and risk traits in farms in Ardabil, Khalkhal, Nir and Germi counties based on the collected data and market conditions in 1400, using a bio-economic model. The economic coefficient of the traits was calculated using MATLAB software with a unit change in the mean of the desired trait if other traits remain constant in their mean. The studied traits included milk production, milk fat, calving interval, production lifespan, daily weight gain before and after weaning, birth weight, adult body weight, survival rate before and after weaning. The economic coefficients for Ardabil city are 15501/17, 556278, -78829/41, 18325/85, 607695/31, 1984509/5, 47849/36, -34521/69, 676066/77, 3174287/11 Rials, respectively. Khalkhal city 12154/83, 555009/65, -156539/61, 17409/81, 1058103/07, 3480949/26, 83976/43, -43347/37, 3814230/34, 6371210/65 Rials, for Nir city 15281/13, 490212/7,-128232/97, 64858/19, 898225/59,2932385/16,70725/61,-49044/99,2503282/56 5036932/8 Rials and for Germi city 27118/6, 448803/94, -130308/28, 15699/58,908827/54,2990291/35,72192/17,-54554/8,3024142/99,5006904/32 Rials per cow per year were calculated in all production systems The highest income was related to milk sales and the lowest was related to elimination heifers. It was also found that the cost of nutrition has the largest share of the total variable costs. Among non-nutritional costs, manpower costs were the most important factor in increasing costs. The results of the sensitivity test showed that economic coefficients are the most sensitive to changes in feed and live weight prices and the least sensitive to fluctuations in milk and fat prices. The results also showed that livestock diseases and lack of vaccines and drugs are the most important risk factors in a livestock unit and problems with milk transportation and changes in livestock insurance conditions are the least important risk factors, so the most important risks In livestock, there are risks related to production and manpower. Also, the most important risks threatening natural factors include heat and cold stress and drought, respectively. The economic review of the production system causes a better identification of the position of the units and increases the level of awareness of the policy makers and planners of the livestock sector as well as the investors of these types of activities in order to make fundamental decisions or solve the existing problems.

The aim of this study was to determine to Pituitary-specific transcription factor (Pit1) gene polymorphism relationship with milk production in Iranian Holstein dairy cows. For this purpose, blood samples were collected from 110 proof and un-proof Holstein bulls from North West and Tehran breeding centers of Iran. After performing extraction steps using modified phenol-chloroform method, PITI exon 6 polymorphism was determined with PCR-RFLP and HifI restriction enzyme. Two alleles and three genotypes were observed. Hinf1+ (G) allele and GG genotype were the more frequent. Allelic and genotypic variations in years do not show a specific trend, and for most of the years, the G allele was more frequent. The results of analysis of variance showed that PitI-HinfI polymorphism was not significant effect on milk, fat, protein production, fat percentage and protein content (p>0.05). Allelic replacement effect results showed that allele change from G to A did not have a significant effect on any of the studied traits. Based on the results of this study, it can be concluded that for the use of this gene in the of milk production traits improvement, further research is needed.

The objective of this study was to investigate the additive effect of 1000, 2000, 4000 and 8000 IU/kg of vitamin D3 on the productive and egg quality characteristics in Japanese quail. 320 adult Japanese quail were used. Experiment was done in a randomized complete block design with 5 treatments, 4 replicates and 16 quails in each replicate (12 female and 4 male birds) for 42 days. After 2 weeks of treatments, the productive characteristics of birds were recorded weekly for 6 weeks. At the end of experiment, 5 eggs were selected randomly from each replication and egg quality traits were examined. Feed conversion ratio and also some egg quality parameters including eggshell weight, egg width and diameter of thin albumen were influenced by levels of vitamin D3 (p<0.05). Although the egg quality parameters had no significant difference with control, but the egg shell weight and egg width percent were increased with increase the levels of vitami D3 from 4000 (15.90 and 2.67, respectively) to 8000 (14.41 and 2.51, respectively) IU/kg (p<0.05). The feed conversion ratio in 4000 IU/kg of vitamin D3 (3.68) was significantly lower than the control (4.22) (p<0.05). The other egg quality characteristic as well as feed intake, percentage of egg production and egg weight were not affected by treatments (p<0.05). The results of this study show the improvement of feed conversion and eggshell weight and egg width in Japanese quail's, especially at the level of 4000 IU/kg of vitamin D.

In this study, records of 7 herd first lactation dairy cows were used. Data was collected from 2003 to 2013 by Aria Delta gene and during this study were evaluated. Traits in this study included production (milk, fat, protein yield), type (body depth, angularity, support udder, , fore udder attachment, udder depth) and reproductive (open days and age at first calving) and length of productive life traits. Data analysis was performed by restricted maximum likelihood procedure using wombat software. Heritability estimates of milk, fat, protein yield, , 0.28, 0.49, 0.42 and heritability of age at first calving and open days 0.69, 0.07 and heritability of body depth, angularity, support udder, fore udder attachment, udder depth, respectively, 0.27, 0.25, 0.12, 0.05 and 0.36 respectively and heritability was estimated length of productive life 0.2. . Genetic correlations were between milk and fat yield and genetic correlation between milk and protein yield 0.12 and 0.05 respectively. Genetic correlations between of open days and age at first calving traits 0.21 respectively. Genetic correlations among type traits in the range of -0.51 to 0.72 and phenotypic correlation between type traits in the range of -0.19 to 0.22, respectively. The greatest positive genetic correlation was estimated between body depth and angularity 0.7 and the highest negative genetic correlation between the body depth and udder depth -0.51. The estimated genetic correlations between production, reproductive and length of productive life traits ranged from -0.51 (length of productive life traits and protein yeild) to 0.63 (age at first calving and fat yield). Considering negative genetic correlation between production and reproduction traits, planning of selection programs in dairy cows based on a combination of production and reproduction traits is recommendable. Genetic correlations variable among type traits and longevity in the range 0.01 to 0.39.