مجله تحقیقات دام و طیور
سال پنجم شماره 1 (1395)

The aim of this study was to investigate effects of feeding barley grain during late gestation and early lactation on productive performance of maiden Lori-Bakhtiari ewes. Thirty-two maiden ewes were randomly assigned to equal two treatments as the control (fed custom ration) and the supplemented (fed custom ration plus 400 grams/day/head barley grain during 7-13 days before to 10 days after parturition). The lamb's birth weight was measured. Lambs sex, type of birth and mortality were recorded. Each ewe was individually observed for determine lambing difficulties. Lambs were weighed at 10 days, one month and four months (weaning) of age. The average daily gain between birth to 10 days, birth to one month and birth to weaning age were calculated. No significant difference was found for lamb's birth weight among treatments. Lambing difficulties was not observed in ewes of two treatments. The average daily gain from birth to 10 days (P

In this study, (co) variance components, genetic and phenotyping parameters for body weight traits at different ages of Zandi sheep breed were estimated. Birth weight, weaning weight, 6-month weight, 9-month weight and yearling weight were studied. The data were collected during 1991-2011 by Nakhjir breeding station in Tehran. (Co) variance components were estimated by Bayesian statistical method based on Gibbs sampling technique. Environmental factors of birth year, sex of lamb, birth type and mother's age were significant on all traits. Appropriate fitted models (based on lowest residual variance) for birth weight, weaning weight, 6-month weight, 9-month weight and yearling weight were found to be models 5, 5, 2, 1 and 1, respectively. Direct heritability was found to be 0.15±0.01, 0.26±0.003, 0.21±0.002, 0.25±0.003 and 0.26±0.001 for the traits, respectively. Maternal heritability of birth weight and weaning weight were 0.11±0.01 and 0.06 ±0.001, respectively. The results revealed that growth traits are more influenced by mother’s genetic factors in the early of age. With increasing the age of lamb and decreasing dependency to the mother, the significance of maternal effect reduced. Low to moderate heritability of the traits indicate that selection for these traits will result in a low to moderate genetic improvement.

The current study was carried out to determine chemical composition and some fermentation parameters of five rangeland plants species in Saral rangelands of Kurdistan province including Ferula haussknechtii, Astragalus curvirostris Boiss, Astragalus angustiflorus, Poa bulbosa var vivipara and Hypericum scabrum at three phonology stages(before flowering, flowering and seed yielding) using gas test technique. Gas production was recorded at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h of incubation. The experiment was conducted in completely randomized design. Results of this study showed that crude protein content of Astragalus angustiflorus at three phenology stages were the highest (P

In recent years, considerable progress in knowledge at different fields of life sciences has been occurred and resulted in discovery of important biological pathways associated with human diseases as well as important economic traits in animals. In a reaction mechanism involving many cells that are linked together. Product in each reaction can be used in the next reaction as a reactant and thus metabolic network can be formed. There are same fact about relationships between genes in regulatory networks and the products. Analysis and simulation of metabolic networks is one of the topics discussed in system biology that causes understanding molecular complex relationships in cell. The concept of systems biology is to identify mechanism of cell components or complete being and understanding growth and development paths. The discovery of this mechanism is possible using numerical data and analyzing the interaction of elements involved in the system that makes predicting the characteristics and performance of the components in biological pathways. The basic topics of this knowledge, the study of biochemical pathways and the use of different genomic information in identifying unknown paths and complete it. General purpose systems biology is modeling of biological processes and understanding the processes within cells in respond to changes in the environment. Use this knowledge to the test and characterization of isolated parts of a cell, the cell structure and dynamics of the total available will be checked.

This study was carried out to evaluate the effects of some important effective nutritional management strategies on laminitis prevention and some production, reproduction and economical indexes. For this purpose, a questionnaire were distributed among 75 commercial dairy herd of Gorgan district to investigate dairy herd’s circumstances from view point of implementation of these nutritional strategies and important production, reproduction and economic indexes. Considered nutritional management strategies were: proper ratio of forage to concentrate, use and non-use of feeder, use of sodium bicarbonate as a buffer compound, use of biotin as effective vitamin to lameness prevention, use of mineral and vitamin additive in transition period, use of total mix ration to acidosis prevention, that assayed their effects on dependent or response variable that included average milk production, milk fat percent, losses percent, average days in milk, number of insemination per success fertility, average fertility, laminitis incidence rate and treatment costs, culling percent and milk decrease percent by applying a multivariate linear regression. The results indicated that effects of these management strategies on some production and reproduction factors were statistically significant. Correlation coefficients showed that there are significant association between mentioned management strategies and production, reproduction and economical indexes.

This experiment was conducted to evaluate the effects of different levels of diet metabolizable energy on performance, egg traits and blood parameters of aged laying hens. In this experiment 192 Hy-line (W36) laying hens were used from 65-74 weeks of age in 4 treatments, 4 replicates and 12 hens in each replicate in a completely randomized design. The amounts of ME were 2800, 2900 (control group), 3000 and 3100 kcal/kg in 1-4 experimental groups. The highest egg weight, egg percentage, egg mass, the best feed conversion, the lowest feed cost for production each kilogram of egg, the highest egg color index, albumin and yolk, Haugh unit and egg shell thickness were observed in diet contained 2900 kcal/kg ME. High level of energy in diets, reduce the amount of feed intake and egg production, Haugh unit and shell thickness. In using low ME in diet, as the amount of feed intake without egg production improve increased, the production cost increased, whereas the egg color index, eggshell percentage and Haugh unit reduced. Using different levels of diet metabolizable energy did not have any significant effects on blood biochemical parameters and immune cells of laying hens (P