مجله تحقیقات دام و طیور
سال یکم شماره 1 (1391)

Managerial factors have important and lasting impacts on the performance of dairy farms. Main gold of farm management is catch to desirable performance in long time; therefore need to an examination for evaluating managerial factors and explain relation between managerial methods with farms performance. Furthermore mechanization with overcome to technical, climate and time limitation produce, to facilitate management of dairy cattle farms. The multiple attribute decision to make available possible to measure management and mechanization capacity in dairy farms and to consider relation between management and mechanization capacity with performance, profitability and improve firms. This investigation has been included industrial dairy cattle farms in southern Tehran province. Total dairy cattle farms studied in form entire number. Results this investigation showed that among the indicators of management, education had the most weight on the management capacity and automatic milking machines had the most important role in the development of mechanization capacity dairy cattle farms. Results proved have been Positive and significant correlation between management and mechanization capacity with average milk production of each dairy cattle and herd size. Also positive and significant correlation between the management and mechanization capacity were observed. The results investigation showed that along with increasing management and mechanization capacity, profitability increases. Improve management and mechanization capacities of industrial dairy cattle farms can cause improve performance dairy cattle farms.

To estimate variance components and genetic parameters of growth traits in Zandi sheep, 5542 records during years 2005 to 2011 of herds under research center in Qom were used. Estimates of variance components with derivative-free restricted maximum likelihood method (DFREML) and using the animal model was estimated through six models using WOMBAT software. Year of birth, season of birth, lamb sex and birth (singleton and twin) and the herd showed significant effects (P<0.05) in the studied traits. Therefore, it was implemented as a fixed effects model. The magnitude of likelihood logarithm was estimated for the six models for all the traits. To ensure, the constant (AIC) was also used and the best model for each trait was reported. Direct heritability of traits was estimated based on the values of 3, 3, 2, 2, 2, 2, respectively, for total average birth weight, birth weight, total weaning weight, weaning weight, weights of 12 and 24 months of lambs of ewe were found to be 0.18, 0.17, 0.29, 0.23, 0.18 and 0.1, respectively. Average value of phenotypic and genetic direct and maternal traits in each year were estimated using the best linear unbiased prediction (BLUP) estimates, and the genetic trends of the traits were looked at for over 6 years. The average direct genetic birth weight and total birth weight of lambs of ewes and average of total weight and weaning weights of 12 and 24 months using a single-single analysis were 1.33 ± 0.07, 2.28 ± 0.4, 6.68 ± 2.1, 8.57 ± 1.9, 98.54 ± 22.1 and 205.11 ± 25.8 g, respectively.

Common coot (Fulica atra) is a species of waterfowl that is interested in hunting and the local communities bordering the lagoons north of Iran. In this study, 30 individuals of common coot (15 males and 15 females) from the southeastern coast of the Caspian Sea were sampled in winter 2009. The lead, chromium and iron levels in the breast muscle tissues of common Coot were measured using atomic absorption spectrophotometry. Results showed that average levels of lead in male and female were 1.24 ± 0.3 and 1.12 ± 0.3, chromium levels in male and female were 0.15 ± 0.08 and 0.14 ± 0.7 and iron metal were 55.5 ± 18.4 and 54.5 ± 19.04 wet weights, respectively. There was no significant difference between two sexes (P>0.05). The highest contaminations of lead, chromium and iron in males and females were 1.89, 0.33 and 99.8 µg/g wet weights, respectively. There was poor correlation between these elements in muscle tissue. The results of this study showed that the concentrations of lead and iron in breast muscle of common coot from Gomishan international wetland (Southeast of the Caspian Sea) were below toxic levels.

The aim of the present study was to investigate the effect of storage type (drying vs ensiling) ¬on the nutritional value of saffron residues. Chemical composition, degradability parameters and ruminal and post ruminal digestibility of residues were determined using in situ and in vitro (gas production) methods. Experimental data were analyzed based on T-test using SAS statistical software. Results showed that ensiling caused the amount of water soluble carbohydrates and crude protein to decrease and to increase, respectively. Ensiling did not affect the minerals and phenolic compounds content of residues. ¬DM rapidly degradable fraction (a), DM effective degradibility, DM ruminal digestibility and total tract digestibility were not affected by ensiling¬¬. Further, gas production from DM potentially fermentable fraction (b), organic matter digestibility (OMD) and metabolisable energy (ME) content of dried and ensiled residues was the same. The results of this study showed storage type of residues had no effect on their nutritive value, however more in vivo studies on nutritive value of these residues are recommended.

This study was undertaken to estimate genetic parameters for total weight of weaned lambs per ewe joined (TWW/EJ) in first to 4th parities. Data were obtained from 1912 ewes collected during 17 years (1990-2006) by the Zandi sheep breeding station in the Khojir Tehran province. Analysis was carried out by Restricted Maximum Likelihood procedures using univariate and multivariate animal models. Heritability obtained for total weight of lamb weaned per ewe joined (TWW/EJ) in parity one through parity four as 0.065±0.04, 0.100± 0.06, 0.110±0.07 and 0.159±0.05, respectively. In the univariate analysis, two models including genetic additive effects and service sire effect were used. Results showed that effects mentioned above had a minor importance in phenotypic appearances of the studied trait. Random effect variances due to service sire for these traits were low. Additive genetic correlations of total weight of lamb weaned per ewe joined among different parities moderate to high and positive, ranging from 0.454 (between first and 4th parity) to 0.723 (between first and 2th parity). The corresponding estimations for phenotypic correlations ranged from 0.034 (between first and 3rd parity) to 0.414 (between first and 2rd parity). Considering high genetic correlations between first and subsequent parities, selection for increasing reproductive performance can be based on total weight of lambs weaned per ewe exposed at first parity.

Growth hormone (GH) is one of important hormones that affect growth and production traits in mammalian. Growth hormone gene has been used as a candidate gene for marker-assisted selection in different ¬domestic livestock species. In this research, for investigation of genetic polymorphism of the gene, blood samples (180 samples) were obtained from animals located in shirang station, Golestan. DNA was extracted from blood samples and a 365 bp fragment from the exon 5 of the ovine growth hormone gene amplificated by polymerase chain reaction. Then PCR products were analyzed by SSCP method on 8% polyacrilamide gel¬. Single strand conformation polymorphism (SSCP) analysis showed three conformational patterns for this gene. There was found no significant difference between milk composition and GH patterns in this population. Results showed a significant difference between observed and expected frequencies indicating that there was not Hardy-Weinberg equilibrium.