جستجوی مقالات مرتبط با کلیدواژه « مقاومت » در نشریات گروه « علوم دام »

The aim of present study was to investigate the effect of selection against ascites syndrome on different traits body growth, internal organs, and bloodparameters 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 werebred 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 traitsin SUS and RES were performed by correlation statistics, Chi-square test, and GLM procedure of SAS software (version 9.1), respectively. Thecorrelation between ascites susceptibility in different families indicated that families that showed more ascites under AIC also had more ascites underNCC. Comparative study of different traits in susceptible and resistant groups showed that in SUS, body weight, growth rate and respiratory capacitywere significantly lower and blood partial pressure of carbon dioxide was significantly higher than RES (P<0.05). In the present study it was shownthat selection against this syndrome not only does not reduce growth rate in the investigated broiler line, but also improves growth traits and resistanceto this syndrome in the mentioned line.

Received: July 28, 2015 Accepted: July 12, 2017 1MSc Student, Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran 2Professor, Department of Animal Science, Faculty of Agriculture, University of Tabriz, Tabriz, Iran 3Professor, Department of Pathobiology, Faculty of Veterinary Medicine University of Tabriz, Tabriz, Iran *Corresponding author: [email protected]
Nowadays, beside of production traits, the characteristics of genetic resistance to diseases is considered as animal breeding aims in animal breeding. There is a growing interest by producers and consumers in the production of meat animals with minimal chemical input to reduce chemical residues in the meat and to increase the sustainability of livestock production. Selection of superior sires with identified resistance should be possible because parasite resistance that usually measured by fecal egg counts (FEC) or blood packed cell volume (PCV), is moderately heritable. One option to control helminth infections is to breed sheep that are resistant to these parasites. Genetic variation in response to parasite infection has been documented in the previous studies in some sheep breeds, mostly involving tropical and subtropical breeds, such as the Red Maasai, St. Croix, Florida Native, and Barbados Blackbelly. These breeds have consistently been more resistant to trichostrongyle infections than temperate breeds, such as Dorset and Rambouillet. The objective of this study was to evaluate differences between blood packed cell volume (PCV), parasitic nematode eggs per gram of feces (FEC) and FAMACHA scores of Ghezel breed and Ghezel-Baluchi crossbreds and determine that which group is more probable resistant to nematode parasites.
Material and Data were obtained from 24 one year-old lambs belonging to two genetic groups. Genetic groups including Ghezel (n= 12) and Ghezel-Baluchi (n=12) crossbreds. Ghezel × Baluchi group was containing 50% of Ghezel breed and 50% of Baluchi breed. Samples were collected at two different times on the 2012/2/19 and 2012/3/4 in the Khalat pooshan research station, Tabriz, East Azerbaijan. All lambs were born in the winter of 2011 and they were not given anthelmintic before and they were at the same environmental conditions. Fecal samples were collected directly from the rectum of animals and samples were tested by the method of Clayton Lane. The FEC were obtained for nematodes of Nematodirus (spp.), Marshallagia(spp.), Trichuris(spp.) and unknown nematode eggs. The other measured traits included body weight, PCV and Famacha test. All data except PCV were analyzed by the MIXED procedure of SAS software.Birth weight and blood packed cell volume were analyzed by the procedure of the GLM.
Results showed that the effect of the genetic group on nematodes eggs per gram of feces and Famacha test was significant (P The Ghezel-Baluchi crossbred ewes appeared to be more resistant to infection than the Ghezel breed in natural grazing condition. Crossbreeding of Ghezel and Baluchi sheep breeds increased resistance to internal parasites of the traits measured in this study. As a general conclusion, this research attempted to find resistance traits in relation to domestic parasites in the domestic environment. These characteristics have been investigated by veterinary parasitologists for many years, but animal breeders also need to consider the issue of improving the genetic resistance of sheep to nematodes, and more precisely how they measure the relevant traits and expressions to use in selection of breeder rams and ewes. It seems that crossbreeding of the Ghezel sheep breed with Baluchi breed increases the relative resistance to internal parasites in terms of Famacha, EPG and PCV as measured in this research. In the future there are two needed subjects in this area of animal science: a) to do more investigations to find exactly genetic explication for the relative superiority of crossbreds to pure breeds; and b) the discovery of the nature of the polygonal or non-additive nature of genetic resistance to nematodes in small ruminants.

The aim of the present study was to investigate the physicochemical performances at three sites on skin, namely the diagonal, neck and leg based on different age groups. Eighteen skins pieces in 6 m, 6 m to 1 yr and 1 yr to 1.5 yr of age were selected to represent means of the respective age groups with regard to skin area. The skin area were7.4±1.41, 13.5±1.4 and 18.2±1.1 ft2 for the ostriches, respectively. The diagonal region, neck and leg parts were approximately 81.5, 10.1 and 8.4 percent of the skin area. The areas increased with an increased chronological age at all sites. Average skin area increased at a rate of 0.9 ft2 per each months of age. Average and range of thickness of the leather were 1.5±0.1 (0.6 to 3.0) mm, breaking load 22.2±3.3 (4.9 to 49.2) kgf, tensile strength 146.3±17.1 (70.5 to 269.7) kgf/cm2, percentage extension 58.7±4.9 (21.5 to 93.3) % and density were 0.6±0.05 (0.4 to 0.9) g/cm2. It was evident that leather thickness increased with age. A similar tendency was observed for tensile strength (P12 months of age (P

The study was consequently investigated effect of different tanning methods on apparent density, thickness, tensile strength and also extension percentage in three different tanning (chromic, alum and vegetable) of grown part of ostrich skins (n = 15; 12 to 14 months). Average apparent density and thickness of leathers were 0.7 ± 0.0gr/cm2 and 1.7 ± 0.1 mm, respectively. The breaking load, tensile strength and extension of chromic tanning leather (33.0 ± 4.9 kgf, 197.2 ± 23.9 kgf/cm2 and 53.3 ± 7.0 percent) were more than alum tanning leather (27.4 ± 5.5 kgf, 161.7 ± 26.7 kgf/cm2, 46.4 ± 7.8 percent) and vegetable tanning leathers (13.0 ± 4.5 kgf, 70.7 ± 21.8 kgf/cm2 and 40.1 ± 6.4 percent). However, the best physical quality was found in the chromic tanned leather for ostrich skin proccesing related to alum and vegetable leathers.

This research was carried out to compare the physical effectiveness of grape pomace(GP) with alfalfa hay in Makui sheep. Four adult male Makui sheep with 40±1.2 Kg livebody weight were selected. In this experiment, three treatments including alfalfa hay asa basal diet (control), white GP (WGP) and red (RGP) were separately substituted at50:50 in a ratio with alfalfa hay as experimental diets. The diets were fed over 10 days. Chewing activity of sheep was determined by direct visual observation over 24 h and physical effectiveness factors was done using Penn state separator sieves method. The result of this study showed that the value for physical effective NDF in basal diet was significantly more than WGP and RGP. The physical effective NDF of basal, RGP and WGP was 0.96, 0.68 and 0.61, %, respectively. The distribution of particle on 19 (P<0.0004), 8 (P<0.0001), 1.18 (P<0.0037) sieves were significantly different. Chewing time for basal ration, RGP and WGP mixes was significantly different. The results of the current experiment showed that substitution of alfalfa hay with GP significantly decreased total chewing activity and rumination time in experimental animals in comparison to those were fed with alfalfa hay.