نشریه پژوهش های علوم دامی
سال بیست و دوم شماره 3 (پاییز 1391)

This experiment was conducted to evaluate the effects of wheat and barley based diets supplemented with probio-enzyme on performance، carcasses quality and blood metabolites of broiler chickens. Experiment was designed according to completely randomized design with 300 of Ross 308 broilers on 5 treatments and 3 replicates (with 20 bird in each replicate) for 42 days in two period included starter (1-21 days) and grower (22- 42 days). Experimental diets included: 1) control (diet without wheat، barley and probio-enzyme، 2) diet with 15% wheat and 15% barley with no probio-enzyme، 3) diet with 15% wheat and 15% barley with 0. 05% probio-enzyme، 4) diet with 15% wheat and 15% barley with 0. 1% of probio- enzyme، 5) diet with 15% wheat and 15% barley with 0. 15% of probio-enzyme in starter period، in grower period the inclusion level wheat and barley increased to 30%. The results showed that there were significantly difference between treatments regarding performance، carcasses quality and blood metabolites of broiler chickens (P<0. 05). The best feed efficiency in starter period (1. 51) was observed in birds receiving treatment 2، but in grower period observed in control group (2. 04). The highest percent of liver (3. 01%) and breast (33. 53%) were observed in 2 experimental group and the highest percent of gizzard (2. 67%) was observed in control group. The lowest percent of hetrophile (9. 67%) was resulted in 4 experimental group with using 0. 1% probio- enzyme. The overall results of the present study indicated that in broilers using 15% wheat and 15% barley in starter diets and 30% wheat and 30% barley in grower diets without any adverse effects on performance، carcasses quality and blood metabolites is possible and using probio– enzyme، can reduce the percent of hetrophile cells.

This study was carried out to determine the nutritive value of tomato pomace treated with 0، 1 and 2 percent urea using nylon bags and gas production techniques. In this study two rumen canulated steer Gizel sheep with average BW 351. 8 kg were used for in situ assay. The gas production was measured at 2، 4، 6، 8، 12، 16، 24، 36، 48، 72 and 96 h and ruminal degradability was measured at 0، 2، 4، 6، 8، 12، 16، 24، 36 and 48 h. Result showed that dry matter degradability of treatments processed with 2 and zero percent urea in 48 hours after incubation was 56. 10 and 47. 92 percent، respectively that had a statistically significant difference. Crude protein degradability in tomato pomaces treated with 2 percent urea and control treatment at 36 h after incubation showed significant differences. The amount of gas production of control and treatment with 2 percent urea at 72 h were significant difference (P<0. 05). Metabolizable energy (ME) of tomato pomace trated with 2 percent urea and control treatment showed significant difference (P<0. 05). According to obtained data in this study، tomato pomace treated with 2 percent urea had the highest degradation rate of dry matter، crude protein and metabolizable energy than the other treatments resulting a high performance.

This study was conducted to estimate genetic parameters of reproduction traits in Mehraban sheep. The data were collected from Mehraban sheep flocks of Hamedan province، during 1994 – 2008. Variance components of the studied traits were estimated using univariate animal models with derivative free approach of restricted maximum likelihood. Heritabilities of age at the first lambing، litter size، number of lambs born per year and number of total lambs born per ewe were estimated as 0. 15، 0. 06، 0. 04 and 0. 01، respectively. Estimates of heritability for litter average birth weight، litter average weaning weight، total litter birth weight، total lambs birth weight per year، total lambs birth weight per ewe، total litter weaning weight، total lambs weaning weight per year and total lambs weaning weight per ewe were 0. 04، 0. 17، 0. 08، 0. 03، 0. 09، 0. 11، 0. 09 and 0. 23 respectively. Estimates of the variance due to permanent environmental effects were negligible for the studied traits; therefore the estimates of heritability and repeatability for each trait were approximately equal. It was concluded that consideration of litter average weaning weight and the age at the first lambing، in the selection programs، is probably an effective method for genetic improvement of reproductive efficiency in Mehraban sheep.

This research was carried out in order to determine of chemical composition، metabolizable energy، digestibility and content of gas production of range species Artemisia siberi Besser. Artemisia siberi Besser were sampled in during the three physiological growth phase (vegetative growth، flowering and seed) and was chosen from two regions with different altitudes (Neor was around 1800-2000 meters and Hir around 1300-1500 meters). The obtained crude protein in vegetative growth were 15. 76 and 17. 87 (%) for Hir and Neor regions، respectively. The amount of crude protein decreased with aging plant. Data analyzed completely according to randomized design and it was based on factorial array. Degradability of Artemisia were high in the vegetative growth phase and it showed significant difference with flowering and seed stages (P<0. 05). Artemisia has more digestibility and metabolizable energy in the stage of vegetative growth. Metabolizable energy of Artemisia was estimated 9. 95 and 9. 85 MJ/Kg in the Hir region for vegetative growth and flowering stages، respectively. These values in the vegetative growth and flowering stages in the Neor region were estimated 10. 37 and 10. 13 MJ/Kg، respectively that it showed significant difference with the seed stage (P<0. 05). The organic matter digestibility of Artemisia was not significant difference in the vegetative growth and flowering stages، but it showed significant difference with the seed stage (P<0. 05). The organic matter digestibility of Artemisia in the different growth stages in Hir region was estimated 67. 33، 66. 04 and 56. 06 (%)، respectively and in Neor region was obtained 70. 04، 68. 00 and 61. 35 (%).

The aim of this study was to assess the effects of some mycotoxin absorbents on biochemical and hematological parameters of broiler chickens fed on aflatoxin B1 contaminated feed. Total of 200 broiler chickens Arian 386 in a completely randomized design with 5 treatments and 4 replications (10 birds for each replication) were used. Experimental treatments were: group A or negative control (soybean meal and corn diet)، group B or positive control (basal diet+1mg/kg aflatoxin B1)، groups C، D and E were formed by addition of 2. 5 g/kg of Milbond-TX، natural zeolit and Polysorb، into diet B، respectively. The results showed that aflatoxicosis significantly increased AST، ALT and LDH enzymes activity in comparison to the negative control group (P<0. 05). Adding absorbent additives decreased these enzymes activity compared to positive control. The amount of total protein and serum albumin were significantly lower in positive control group compared with the other groups (P<0. 05). The use of additives significantly reduced the serum cratinine in comparison with positive control group (P<0. 05). Addition of zeolit reduced serum uric acid compared to other absorbents. Serum cholesterol، triglyceride، glucose، calcium and Zn were not affected by aflatoxicosis (P>0. 05). Red blood cell counts in positive control group was significantly lower than the other groups except E (P<0. 05). Hematocrit in positive control group was significantly higher than the negative control group (P<0. 05). The hemoglobin value and erythrocytes osmotic fragility were significantly influenced by the type of added absorbent. In conclusion natural Iranian zeolit as well as the two commercial mycotoxin absorbents reduced the aflatoxin B1 induced biochemical and hematological alterations in broilers.

The main objective of this study was to compare two test day models (with fixed or random regressions) applied for genetic evaluation of protein yield in Holsteins dairy cattle of Razavi Khorasan Province. The data set was included 57،551 protein test day records from 7036 first parity Holstein cows calved between 2003 and 2006. Total number of herds، sires، dams and animals in pedigree file were 138، 590، 6091 and 13117، respectively. Contemporary groups were defined based on combining herd-year-season of production-milking times (HYST). The response variable was test day protein yield for which there was an average 918 gr (SD=225. 8 gr) in the whole data set. In fixed and random regression test day models، HYSM (fixed effect)، calving age (linear and quadratic covariables)، Holstein gene percentage (linear and quadratic covariables)، and random effects of additive genetic and permanent environment were included. To take account of the shape of the lactation curve at phenotypic، genetic and environmental levels، orthogonal Legendre Polynomials were also included in the models so that the order of the Legendre fit was zero and third order for fixed and random regression test day models، respectively. Fixed and random regression test day models were run using WOMBAT and DXMRR software، respectively. The results indicated there was a very high rank correlation coefficient (0. 936) between predicted breeding values (PBV) which was statistically significant (P<0. 001). Averages PBV of progeny were found to be -0. 209 and -0. 037 gr for fixed and random regression test day models، respectively which were not significantly different. The results also indicated that the highest (0. 197) and the lowest (0. 049) of heritability were found for the first and eighth month of the lactation course. It can therefore be concluded that fixed regression test day model could be used instead of random regression test day model in genetic evaluation of Iranian Holstein dairy cattle for protein test day records in particular where computational capacity is limited for running a random regression test day model at the national scale.

An experiment was conducted to study the effect of different dietary metabolizable energy levels on performance of Lohmann LSL-Lite strain pullets at the rearing periods. A total of 196 3-week old chicks were randomly allocated to 7 experimental diets with different metabolizable energy levels (2400، 2500، 2600، 2700، 2800، 2900 and 3000 Kcal/kg)، 4 replicates per diet and 7 birds per replicate pen. Level of metabolizable energy 2800 Kcal/kg as the control group was considered، and all data were analyzed in a randomized complete block design. Mash feed and water were available for ad libitum consumption. Total of the rearing periods was divided to 3 periods: grower (4-8 weeks)، developer (9-16 weeks) and prelaying (17-18 weeks). Comparing the results of other diets with control diet at the entire periods showed that reducing the level of dietary metabolizable energy up to 2500 Kcal/kg do not significantly affect feed intake (P>0. 05) and feed conversion ratio (P>0. 01)، in addition to، the cost of this metabolizable energy level was significantly lower than control diet. Under the conditions of this experiment، the conclusion based on feed conversion ratio in each period show that the best level of metabolizable mnergy in growth، development، and the prelaying periods، respectively can be 2600، 2500 and 2700 Kcal/kg diet.

This research was conducted to evaluate performance parameters of two strains of Aryan and Ross broiler chicks fed a diluted diet. For this study، 320 sex determined broilers from two strains of Aryan and Ross fed according to diluted nutrient requirements recommended by National Research Council for 49 days. This trial was conducted as a 2×2 factorial arrangement in a completely randomized design with four replications and 20 chicks per replication. The results of this study showed that with feeding of a diluted ration، the Aryan broilers have significantly (P < 0. 01) more body weight gain and feed intake in comparison to the Ross broilers. However، production indices and feed conversion ratios are not significantly different. There was not a significant difference in carcass traits between Aryan and Ross broilers. The results obtained from this study show that، with a diluted ration، the Aryan broilers have relatively better rearing properties in comparison to Ross broilers.

This experiment was conducted to investigate the effect of different levels of poultry by- product meal (PBPM) produced two slaughter houses Golestane province on performance and carcass characteristics of broiler chicks in a completely randomized design. Dietary treatments consisted of a control corn- soybean diet، and 3، 6 and 9% levels of PBPM produced by slaughter house1 and 3، 6 and 9% levels of PBPM produced by slaughter house2 that was prepared for starter (o- 21 d) and grower (22-42d) periods. Thus، there were seven treatment groups with 4 replicates and 20 Ross 308 mixed sex chicks per replicate. Results chemical analysis of PBPM samples showed that the amount crude protein، ether extract، calcium and net energy PBPM 1 were 60. 77، 12. 34، 3. 21%، 4459. 73 kcal/kg and PBPM 2 were 62. 24، 17. 45، 3. 52 % and 4786. 36 kcal/kg respectively. Weight gain of chicks fed with level of 9% PBPM 1 was significantly (P<0. 05) lower than the control (1696 gr vs 2056 gr). Using of PBPM 1 and 2 had no significant effect on feed intake، feed conversion ratio، protein efficiency ratio and carcass composition in whole experimental period. By increasing PBPM in level 9% of PBPM of houses 1 and 2 feed cost significantly decreased vs control (P<0. 05)، but there was no significant difference among groups in feed cost per 1 kg weight gain in 42 days of age.

In this research a total of 46،563 wool weight records belonging to 12،842 Baluchi sheep (represented 414 sires and 4892 dams) collected during 24 years (1983-2006) from two herds of Abbas Abad breeding centre، Mashhad were utilized to study the effects of some environmental and genetic factors. A linear mixed model was used to evaluate fixed environmental factors using SAS software. The year and month of shearing، sex، birth type، age and shearing order of lamb had statistical significant effect on wool weight. Phenotypic trend estimation was 13. 12 g per year which was statistically significant. Genetic analysis of the trait was undertaken by a repeatability animal model using DMU software. The estimates of additive genetic and permanent environment variances، heritability and repeatability were 9293. 58، 6758. 45، 0. 092 and 0. 159، respectively. The estimation of genetic trend for wool weight was 3. 49 g per year which was statistically significant. Mean breeding value for wool trait was significantly lower in male (24. 67 g) than female (32. 11 g) lambs

The aim of this study was to investigate the effect of two commercial extenders without egg yolk: Bioxcell and Andromeda on freezing ability in Iranian Holstein''s and Brown Swiss''s bull. Semen was collected from 8 bulls (4 Holstein، 4 Brown Swiss) in Iranian Progeny Test Center using artificial vagina. Semen were mixed (2 ejaculated / bull / week for 4 weeks) and allocated to the extenders in two equal sections. Freezing was conducted using IMV semi-automatic equipments. The percentage of motility (MO)، progressive motility (PPM) and viability (VI) of these samples were evaluated before freezing and after thawing by standard method. The effect of extender، breed and interaction between them on the MO، PPM and VI after thawing was significant. Mean MO، PPM and VI were high (P<0. 01) in Bioxcell than Andromeda in per two breeds. The highest mean motility، progressive motility، viability was observed in the treatment Bioxcell in Holstein breed. Results showed Bioxcell extender in comparison with Andromeda extender had more ability to maintain sperm quality during freezing procedure.

To analyze the effect of some environmental factors on the number of insemination per conception، 9125 insemination records obtained from first lactation Holstein cows which were inseminated during 1989-2008 were utilized. All records were collected from a very large dairy herd which comprised of two units. Poisson model was applied as the statistical model. In the model، effects of year and month of insemination، technicians and units were fitted as fixed. Also temperature and relative humidity in the day of insemination were fitted as covariates. The statistical model was run using GLIMMIX procedure of SAS software. The results showed the effects of year of insemination، unit and temperature on the number of insemination per conception were significant، but month of insemination، technicians and relative humidity didn’t have statistically significant effect on the number of insemination per conception.

The Advantageous effects of artificial insemination (A. I.) on the stability of performance، productivity، profitability and strengthen in dairy cattle enterprise have been confirmed by several studies. In spite of such benefits، application of this technique is less acceptable by some dairy cattle breeders. The aims of the present investigation were studied the status of A. I. technique application in Jiroft city، southern part of Iran، and identification of the affecting factors on the adoption of this technique by local dairy breeder. Therefore، 200 dairy cattle farms were investigated during 2009-2010. The obtained results revealed that 61 percent of farmers use A. I. To determine the factors affecting the adoption of the A. I.، Logit model was estimated using maximum likelihood method. The results showed that the number of dairy cattle’s in the farm، literacy، distance to city center، attitudes to A. I.، services provided by governmental institutions and non-farm employment are effective factors on the adoption of A. I. technique.

The existence of genotype by environment interaction on milk production traits of Iranian Holstein dairy cattle was investigated by considering recorded performance of daughters of sires at different calving seasons regards as different traits. In the current study، recorded data on Holstein cows between 2001 and 2010 were used. For production traits (milk yield، fat percentage and protein percentage)، genotype by environment interaction were estimated by using multiple-trait random regression sire model. Additive genetic and permanent environmental variances of milk production traits did not vary at different calving seasons. Heritabilities for 305-d production in spring، summer، autumn and winter calving seasons were 0. 26، 0. 29، 0. 27 and 0. 24 for milk yield، respectively; 0. 28، 0. 30، 0. 30 and 0. 28 for fat percentage، respectively and 0. 42، 0. 45، 0. 40 and 0. 38 for protein percentage، respectively. The genetic correlations for 305-d milk production traits between different calving seasons were higher than 0. 93 and that no significant genotype by environment interaction was indicated. The Spearman rank correlations between estimated breeding values of 20 top sires between summer and autumn and also between summer and winter were 0. 68 for protein percentage and the re-ranking of sires between these seasons were observed. In conclusion، results from this study indicated that there were interactions between genotype and season of calving for milk production traits in Iranian Holsteins dairy cows. The results of current study can be used to increase the accuracy of sire selection.

Forty eight crossbred Holstein-Kordi cows in 3rd lactation period and from 3rd months of parturition were studied during a four months period. Cows allocated based on body weight in two groups as 550 and 650 kg with two replicates in each group. The mixed model was used for statistical analysis of continuous data. The logistic analysis method was applied for analyzing of data based on the occurrence of acidosis. The experimental treatments were: total mixed ration or TMR (T)، separate feeding of forage and concentrate (P) and traditional feeding method (C). The experimental diets were fed three times daily. The results of study showed that the treatments had a significant effect on milk production and the use of a balanced ration was increased milk production، and decreased the fat and protein percentage (P<0. 05). The effects of village، body weight and month of lactation had a significant effect on milk production (P<0. 01). TMR feeding resulted in lower acidosis incidence as well (P<0. 05).

Thirty-six Moghani ewes with a history of two parities, weighing 55±5 kg were allocated in 3 groups (n=12) to investigate the impact of flaxseed and soybeans grains in the complementary randomized design on the ewes metabolites and hormones in blood, and their reproductive performance through a period of the 35 days. The experimental treatments were: 1- Flaxseed (F) (5% of total ration dry matter), 2-Soybean (S) (5% of total ration dry matter) and 3- Control (C) (without seed oil) respectively. Isonitrogenous (9% CP) and isocaloric (3.6 Mcal/kg) experimental diets were used. Body condition score of ewes at the beginning of experiment were 2.5 and reached to about 3 at the breeding time. Ewe's estrus was synchronized using CIDR 14 days before mating. 24 hours after CIDR removal, ewes were mated randomly with 5 rams of the station in the first of June. The usage of oilseeds improved fertility and lambing rate (P<0.05). Glucose, cholesterol, insulin and estrogen hormones levels of serum were higher in experimental diets containing flaxseed and soybean seeds than the control group (P<0.01).