AGRICULTURAL RESEARCH
Year:2004 | Volume:4 | Issue:1|Papers Count:6

In this study 1874 reproductive records from mating of 682 ewes with 150 rams during 1991 to 1998 in the station of Genetic Improvement of Bakhtiari sheep breed were used to estimate the genetic parameters of reproductive traits by Henderson’s III and DF-REML methods. The effect of environmental factors such as mating year, age of ewe at mating and mating time were significant (p<0.01, 0.05) on most of reproductive traits. Estimation of genetic parameters for considered reproductive traits with Henderson’s method III were: paternal half-sib heritabilities from 0.14±0.05 to 0.28±0.07, maternal half-sib heritabilities from 0.13±0.08 to 0.44±0.10 and repeatabilities from 0.05±0.03 to 0.18±0.03. Estimation of heritabilities with Derivative Free Restricted Maximum Likelihood (DF-REML) procedures was: direct heritabilities from zero to 0.11±0.03 and repeatabilities from 0.03 to 0.20, also phenotypic and genetic correlations among most of the considered traits were positive and from 0.47±0.16 to 0.91±0.02. According to the theory of Henderson’s method III for estimation of parameters, in the considered population, it is assumed that, animals are unrelated and this method does not account for selection and nonrandom mating while these assumptions do not meet in commercial herd such as the herd under study. These assumptions are considered in DF-REML procedures. Then, the estimation of genetic parameters by DF-REML is superior to Henderson’s method III except for repeatability coefficients, which there were a negligible difference between two methods of estimation. It could be concluded that in to increases reproductive rate, improvement of environmental factors is necessary. It seems that selection within breed by itself can not make any major improvement in efficiency of reproductive traits.

To investigate the effect of wet diet in compensatory growth period on live weight, feed convertion, feed intak and carcuss charactristics of broilers, a study was carried out in Ramin Agriculture Reaserch Station. In this study 240 chicks from Arian strain, randomly selected. Weight gain in 7Th week in 0, 10 and 20% of restrict, was 2031.13, 1905.13 and 1907 grams, respectively. The 0% restriction treatment ratio other treatments, was significantly (P<0.05). Ration form(dry and wet), had not effect on final live weight gain (P>o.o5). Feed consumption in 20% restrict treatment was less than other treatments, as such wet ratio consumption was less than dry ration (P<0.05). Food convertion ratio of 0% restrict treatment was less than 10 and %20 restrict (P<0.05). But food convertion ratio not significant between 10 and 20% restrict treatments (P>0.05). Food convertion cofficient of wet ration was less than dry ration (P<0.05). Concerning the carcass weight, braest weight, thight weight, intestine weight and abdominal fat weight, a significant difference between treatments was not found (P>0.05). Intesting weight in wet ration fed groups was (P<0.05).

Cereal by-products may play a vital role in broiler nutrition. The effect of different levels of broken rice substitution in diet was studied in this experiment. In diets, rice was substituted for corn in 3 levels (0, 10 & 20%). Experimental diets were applied in three nutritional phases (starter , grower & finisher), in a 42-day period, on 486 Arian male broilers. This experiment was conducted in 3 replication, with 54 chickens, in each by weighting was done weekly. Inorder to evaluation of growth rate, feed intake and feed conversion ratio the cases were weighted weekly, and blood glucose was measured at the end of each nutritional phase. It has been found that increase in the level of broken rice substitution, decreased feed intake (p<0.05). It also decreased body weight and feed conversion ratio of experimental groups, but these changes were not significant (p>0.05). Total feed cost for 1 Kg live weigh production was completely randomized design decreased by brocken rice.According to the results of this experiment corn graim can be substitution by broken rece up to 20%.

For this study, data of birth weight, 3, 4 (Weaning), 6, 9 and 12 month weights of 2425 Kordy lambs in Shirevan Animal Breeding Research Center were investigated. Variance components and genetic parameters were estimated using animal models and derivative free approach of restricted maximum likelihood (DFREML) procedure. In animal models, lambing year and month, mother’s age at lambing, sex and birth type were considered as fixed effects and direct additive genetic, maternal additive genetic and maternal permanent environmental effects were random effects. Lambing year, sex and birth type had significant effects on all traits. Mother’s age had significant effect on pre-weaning traits (P<0.05). Estimated heritabilities of birth weight, 3, 4, 6, 9 and 12 month weight were 0.15±0.06, 0.25±0.07, 0.23±0.08, 0.14±0.08, 0.13±0.07 and 0.08±0.06, respectively. Estimated genetic correlations between 3 month weight and 6, 9 and 12 month weights were 0.93±0.05, 0.98±0.83, 0.78±0.23 and between 4 month weight and 6, 9 and 12 month weights were 0.90±0.06, 0.99±0.04 and 0.99±0.19, respectively. Body weights at 3 and 4 months of age had highest estimation of hertabibity and strong genetic correlations with other traits. According to results of this study, body weights at 3 or 4 months of age could be considered as a selection criterion.

In this study, the Potential Applied Viscosity (PAV) has been measured on 5 types of raw material in wied varities range.The lowest and highest PAV values were observed for maize and barley, respectively.Cereal PAV caj be properly estimated by extraction at PH, 1.5 without ethanolic treatment. Real applied viscosity(RAV) was affected by temperature of pelleting(2.5mm), The high RAV values were observed only when PAV was also high and the temperature of pelleting was above 90°C. Particle size of extracted flours greatly changes the RAV values and coarse grinding result the low RAV values. It is demonstrated that enzymi activity could not affected by particle size.Excretion and consumption of water relative to feed intake are measured in 5 week-old meat-turkey poults by 5 diets. Regression lines are fixed with the data (for raw material) as the dependant variables, and the diet parameters were as the independent variables.The most efficient equations are based on RAV and potassium on PAV, temperature of pelleting and potassium. The highest R2values was 0.758. According to the expressions of equations, the effects of dependant variables are not increased in this case.