ANIMAL SCIENCE RESEARCHES (FACULTY OF AGRICULTURE, UNIVERSITY OF TABRIZ)
Year:2012 | Volume:22 | Issue:2|Papers Count:15

An experiment was conducted in order to evaluate the effect of different metabolizable energy and lysine levels on the growth performance and carcass quality of Arbor Acres (AA) broiler chickens. A total 180 of one day-old broiler chickens were randomly allocated to each of 6 treatments with 3 replicates in CRD design as factorial arrangement (2 metabolizable energy levels × 3 lysine levels) with 10 sex-mixed birds each. Three experimental bird groups received the experimental diets formulated to meet AA nutrient requirements for metabolizable energy with three levels of lysine (85, 100, and 115 percent of recommended level) and other three bird groups received the experimental diets with 200 Kcal/Kg deficient in metabolizable energy with same three levels of lysine. Except at 1- 14 days of age, feed intake, body weight gain and FCR of broilers were improved significantly (P<0.05) in standard energy level in other growth periods. With decreasing of lysine level in diets, feed intake and body weight gain was decreased at 1-28 days but performance traits were not influenced by lysine levels in other growth periods. The results showed that may be used 85% of recommended level of lysine in diet at 28 -49 days of age. Body weight gain and FCR was improved in standard level of energy at 1-49 days of age. It was concluded that AMEn values were significantly (P<0.05) decreased with declining levels of metabolizable energy and lysine in broiler diets. Dressing percent and thigh weight percent was not affected by metabolizable energy and lysine levels. Breast weight percent and breast meat value decreased with lowering levels of metabolizable energy and lysine in diets.

The aim of present study was to evaluate the effect of ascites on some blood parameters and internal organ weights in the two paternal lines A and B from a commercial broiler line which were selected for higher body weight and lower feed conversion rate, respectively. In total 302 male birds (161 birds from line A and 141 birds from line B) were selected randomly and studied under two treatments of control and ascites. Body weight was measured at 7, 10 and 54 days of age. Moreover the body weight gain, feed intake and feed conversion ratio (FCR) were evaluated within 23 to 54 days of age. At 28, 35 and 42 days of age, the blood gas parameters and hematocrit value were evaluated. At the end of experiment in 54 days of age, all birds were slaughtered and the weight of heart, liver and spleen were measured. Moreover mortality resulted from ascites syndrome in total period experiment was recorded. The results of current study indicated that just body weight at 10 days of age was significant difference (P<0.01) between two paternal lines, so that it was higher in the ascites treatment group. Although the difference between two treatment for feed intake was significant (P<0.05) so that birds in the control group showed higher feed intake compared to ascites group, however the FCR values in whole period of experiment were similar in two treatment. There was no significant difference between birds in two group for internal organ weights like heart, liver and spleen, but right ventricle to total ventricle ratio as an indicator of ascites syndrome was higher (P<0.01) in the ascites group. Although birds in line B and in the ascites treatment showed significantly lower percentage of blood O2 saturation (P<0.05), however for other blood gas parameters and hematocrit value there was no significant difference between two treatment in both lines A and B.

Six lactating primiparous Holstein cows were used in two integrated change over 3×3 squares to investigate the effect of exogenous fibrolytic enzyme (cellulase) on dry matter intake, nutrients digestibility and milk production. This experiment was conducted in three periods of 20 days. The basal diet consisted of 50 percent concentrate (rolled barley, wheat bran, cotton seed, cotton seed meal and mineral supplement) and 50 percent forage (corn silage and alfalfa hay). Treatments were: 1) control (without enzyme), 2) basal diet +0.5g enzyme applied to alfalfa, 3) basal diet+1g enzyme applied to alfalfa. In each period dry matter intake and nutrients digestibility were determined at 14-18 days and milk sampling and milk yield were determinate on the days 19 and 20. Milk yield and 4%FCM production and dry matter, organic matter and neutral detergent fiber digestibility were higher for treatment containing 0.5 g enzyme as compared with 1 g however, dry matter intake and digestibility of crude protein were similar among the groups. Effect of enzyme supplementation on milk fat, protein, lactose and SNF and lactose yield was not significant. Cows receiving diet containing 0.5g enzyme had higher milk fat, protein and lactose compared to other groups and the above mentioned parameters were higher for cows fed diet containing 1g enzyme in comparison to control group. Overall results showed that exogenous cellulase supplementation either 0.5 or 1 g/d for lactating Holstein cows in early lactation increases both dry matter and fiber digestibility and milk production, however the level of 0.5 g/d enzyme supplementation is better.

In this research, economic value for production traits and reproduction traits of Afshari sheep were estimated using a deterministic bio-economic model. In production system of Afshari sheep, the variable costs comprised 99 % of total costs. Revenue sources consisted of meat, milk, wool and manure, where meat with 83.4 % of revenue had the highest effect. Economic value for a trait as the change in profit of production system by increasing one unit in the trait avrage, while avrage of other traits were constant was estimated. After that, milk, wool production and ewe survival were followed. Birth weight had negative economic value. The sensitivity of economic value of various traits to ±10 % changes in feed, non- feed costs and also to meat, wool and milk prices were examined, and the results showed the economic values of wool and milk productions were not sensitive to none of the costs. Also changes in the costs of rearing and marketing had no effect on the economic value for body weight in various ages of wool and milk production. By changing the price of meat, the economic values of all traits except birth weight, wool and milk production were changed, by increasing the price of meat results to increases in the economic values of those traits. Among various factors, meat price had the most effect on the economic value of traits.

The aim of this experiment was to study the effect of fibrolytic enzyme on milk yield and composition, nutrient apparent digestibility and rumen pH of Holstein cows in early lactation period. Fifteen multiparous lactating cows (DIM 30±10, and initial body weight 616±12) in change over design randomly were allocated to one of experimental diets. The experimental diets included: 1) control (with no Natuzyme enzyme added to basal diet), 2) basal diet with 2.5 g/kg of Natuzyme enzyme to kg of DM 3) basal diet with 5 g/kg of Natuzyme enzyme to kg of DM. Design had three periods and five cows allocated to each diet in each period. Individual dry matter intake and daily milk yield, milk composition weekly and body condition score (BCS) changes were measured at first and at the end of each period. Digestibility of nutrients of basal diet was measured with acid insoluble ash as marker. Rumen fluid collected for determining of pH from each cow in every period at zero and 4 h after feeding. Results indicated that 2.5 g/kg of enzyme of DM of TMR increased milk production, %3.5 fat corrected milk (FCM) and energy corrected milk (ECM) compared to the other groups (P<0.05). Milk fat and protein yield increased significantly (P<0.05) in group that consumed 2.5 g/kg of enzyme. Dry matter intake increased significantly in cows consumed 2.5 g and 5 g/kg of DM of enzyme (P<0.01). Body condition score changes were improved significantly (P<0.01) for cows consumed 5 g/kg of enzyme of DM compared to cows fed with 2.5 g/kg of enzyme and control groups. Milk efficiency decreased significantly in cows consumed 5 g/kg of enzyme (P<0.01). Furthermore, just diet with 5 g/kg of enzyme could increase NDF and ADF digestibility in basal diet (P<0.05). The Enzyme had no any effect on rumen pH at zero and 4 h after feeding. Results of the current study indicated that the enzyme with 2.5 g/kg of DM of TMR can be useful in increasing of milk yield of early lactation Holstein cows.

This study was conducted to determine the digestibility and palatability of white and red grape pomace. Experimental feedstuffs were analyzed chemically, and phenol concentration was determined. Then the feeds digestibility measured in vivo and in vitro and their palatability was tested. Four adult male sheep with 40±1.2 kg body weight were used in these experiments. Red and white grape pomaces replaced with alfalfa hay with proportion of 50: 50 to determine the digestibility. The results showed that red grape pomace had more phenol and tannin concentration than those of white grape pomace, thus, reduction of protein concentration, digestibility and metabolizable energy of red grape pomace was expectable. Nutrients digestibility of basal diet including alfalfa hay was significantly (P<0.01) higher than experimental feeds. It may be due to higher concentration of tannin, lignin and neutral detergent fiber in grape pomaces. Lower digestibility of red grape pomace may be attributed to higher tannin concentration in this pomace. Palatability of basal ration (alfalfa) was lower than pomaces. Palatability of white grape pomace (45.5%) was higher than that of red grape pomace (38.16%) (P<0.01). It may conclude that grape pomace can be considered as a good source of fiber and may use in diets of low yield animals to meet the requirements of energy and nitrogen. For increasing nutritive value of grape pomace, it may be better to use chemical treatment and physical processing of such as ensiling, drying and addition poly ethylene glycol which needs more investigation to be done.

This study was performed to study the effect of using CIDR and presynch method with ovsynch program on the pregnancy level of dairy cows. Cows were allocated to three groups ovsynch (control, n=40), presynch+ovsynch (n=40) and CIDR+ovsynch (n=33). They were compared to the rate of blood metabolite concentrations and their effects on pregnancy rate. At the time of insemination 5 ml blood was taken with venoject tubes without anticoagulant, and achieved blood sera were frozen at -20co to test. Achieved Data were analyzed following two models: In the first model using software GLM procedure SAS 9.1, were analyzed the effects of treatment, stage of lactation, milk record monthly and ambient temperature effect on measured blood metabolites. Effect of milk record monthly with probability level (P<0.05) on blood serum glucose was significant and effects of environmental temperature and stage of lactation on blood serum BHBA were quite significant (P<0.01). Effects of treatment and ambient temperature on blood serum estrogen were quite significant (P<0.01) and monthly records of milk had a significant effect (P<0.05). Parity and annual milk production had no significant effects on any of the blood metabolites. In the second model using logistic regression, effects of variables related to animal and measured metabolites on pregnancy were analyzed. Blood serum glucose concentration (P<0.01) and blood serum BHBA concentration (P<0.05) were significant. This means that condition of constant other factors, one unit increasing in serum glucose concentration increase 0.03 units possibility of conversion non-pregnancy to pregnancy and one unit decreasing in serum concentration of BHBA increases 0.22 units possibility of conversion non-pregnancy to pregnancy. Pregnancy rate in presynch+ovsynch program was higher than ovsynch program and CIDR+ovsynch program (4.22%, 12.85%) respectively, which increased the number of pregnant animal in one year. According to the results of this study could be suggested that the presynch+ovsynch program is appropriate method for managing cattle reproduction and increasing production.

Estimation of environmental factors effects and genetic parameters of some reproductive traits including calving interval (CI, n=16108), lactation length (LL, n=5821) and age at first calving (AFC, n=4421) of buffaloes that their calving occurred during 1995 to 2009 in 162 village were carried out. Mean±S.D of the traits were 437±92, 211±47 and 1318±109 days for CI, LL, and AFC, respectively. The provinces of Mazandaran, East Azarbayjan and West Azarbayjan possess the best buffaloes for CI, LL and AFC traits, respectively. Buffaloes that had calving in winter showed the highest calving interval but the lowest lactation length. Estimation of genetic parameters for the aforementioned traits revealed that genetic variation were moderate to high in Iranian buffalo population. Averages of heritability estimates obtained from uni- and bivariate analysis were 0.28, 0.46, and 0.14 for CI, LL and AFC traits, respectively. Genetic correlation between milk yield and calving interval was negative (-0.156) whereas this correlation was positive between milk yield and age at first calving (0.563).

In this study the yield, chemical composition, in vitro digestibility and gas production of forage from 18 different varieties of oat (Avena Sativa L.) was studied. All the oat varieties were grown under the similar agronomic condition in three replicates in a randomized complete block design at Research Farm of School of Agriculture, Razi University. Significant difference (P<0.01) was observed in the yield of forage (15.6 to 26.3 ton dry matter (DM) /ha) from different varieties. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) content varied from 52.2 to 122, 500 to 597, 306 to 400 and 33.1 to 58.0 g/kg DM in forages respectively. The in vitro dry matter and organic matter digestibility (IVDMD, IVOMD) and metabolizable energy (ME) were significant (P<0.01) differences between 18 varieties of oat forage. The variety 12 and V8 had the highest and lowest IVOMD, respectively (674 vs.549 g/kg DM). The mean value of digestible OM yield (DOM) was 10.8 ton/ha. Variety 8 had the highest DOM (13.2 ton/ha). The potential of gas production (A), rate of gas production (c) and lag time (L) indicated significant difference among different varieties. The result of this study emphasized a great variation in chemical composition, digestibility and kinetics of fermentation in different varieties of oat. However the diversity in digestibility and total cumulative gas production was greater.

This experiment was carried out to determine and compare the chemical composition, digestibility and gas production of grain ofVicia sativa, Lathyrus sativus and Vicia ervilia cultivated in Ardabil province. Digestibility was estimated using in vitro methods. The gas production was recorded after 2, 4, 6, 8, 12, 24, 48, 72 and 96 h of incubation. Crude protein content of legume grains were in range of 23.89-29.34%/DM, NDF (31.12-36.63%/DM) and digestible dry matter (71.86-84.93%). Among the tested grains, the grain of Vicia ervilia had highest fermentation parameters, potential gas production and rate of gas production, Short Chain Fatty Acids and metabolizable energy that estimated as 80 mL in 200 mg sample, 0.103 mL h-1, 1.506 mmol, and 11.72 MJ/kg respectively and Vicia sativa grain had the lowest potential gas production (72.18 mL in 200 mg sample), rate of gas production (0.083 mL h-1), Short Chain Fatty Acid (1.313 mmol), and metabolizable energy (10.35 MJ/kg) content. The grain of Vicia ervilia, had higher nutritive value than other tested feeds due to its in vitro fermentation characteristics as well as chemical composition. It was concluded different test feeds had different chemical composition, in vitro digestibility, gas production and metabolizable energy which significantly affected the degradation parameters.

In this research a total of 46466 wool weight records belonging to 12821 Baluchi lambs (6334 males and 6487 females) (progeny of 413 rams and 4879 ewes) born from 1983 to 2006 in two herds of Abbas Abad breeding centre, Mashhad, Iran were utilized to study inbreeding effect on wool weight of Baluchi sheep. Inbreeding coefficient was calculated for individual lambs using pedigree software. Data were analyzed by a linear model using SAS software. Year and month of shearing, age at shearing, inbreeding coefficient, sex and birth type had statistical significant effect on wool weight (P<0.0001). In total pedigree animals, 2441 was inbred (19.4%). Average and standard deviation of inbreeding coefficient for total and inbred population were found to be 0.669±2.60% and 3.90±5.17%, respectively. Minimum and maximum of inbreeding coefficient were 0 and 31.25%, respectively. Average inbreeding coefficients for male and female lambs were 0.708±2.69 and 0.733±2.68%, and for single and twin lambs were 0.684±2.59 and 0.785±2.84, respectively. No statistical significant difference was found between two means of inbreeding coefficients of male and female lambs while statistical significant difference was revealed between two means of twin single and twin lambs (P<0.05). Inbreeding had negative effect on performance of wool in twin male and female lams (P<0.05). Increasing 1% of inbreeding coefficient of twin male and female lambs was accompanied with decreasing 2.86 and 6.62 g in their wool weight, respectively. Annual change trend in inbreeding coefficient for total and inbred population were 0.075% and -0.26%, respectively that was statistically significant (P<0.0001).

This experiment was conducted to investigate the replacement of soybean meal by different levels of canola meal (0%, 8%, 16% and 24%) in wheat or corn based diets on performance and carcass traits of male broiler chickens. The experiment was a 2×4 factorial based on completely randomized design with 5 replicates of 8 birds in each, using 320 Ross chicks. All of chickens received similar ration until 12 day of age, then received experimental rations from 12 up to 42 days of age in two periods, grower (12 to 21) and finisher (22 to 42).Results indicated that different levels of canola meal replacement had no effect on feed intake, body weight gain and feed conversion ratio in the total period (12-42). The interaction between basal diet and canola meal levels on above mentioned traits was not significant. However, the effect of replacement of canola meal was significant (P<0.05) on body weight gain and feed conversion ratio in the grower period. Effect of basal diet (corn or wheat) on body weight gain was significant (P<0.05) during the finisher and total periods. However, chickens fed wheat based diet had increased weight gain in comparison with corn based diet. Increasing levels of canola meal increased percentages of total digestive tract and total intestinal weights (P<0.05), but had not significant effect on other carcass traits (percentage of breast, tight, abdominal fat pad, liver, heart and proventriculus and gizzard).As a while, the results of the present study showed that canola meal can be used up to 16% in wheat or corn based diet.

This experiment was conducted to evaluate the effect of various supplemental fats applied in the flushing diet on reproductive performance, blood metabolites and hormones of Ghezel breed ewes.36 Ghezel sheep were assigned in three treatments for 42 days in completely randomized design. Experimental groups were as follow: control (without supplemental fat in diet), sunflower oil (5% of ration dry matter) and calcium salts of palm oil (5% of ration dry matter). Experimental rations had the same Metabolisable Energy (3.6 Mcal/kg) and Crude Protein (9.2%) contents. CIDR was used for estrus synchronization. Insemination was done 48 hours after CIDR removal. Supplementation of fat resulted in higher levels of blood total serum cholesterol (P<0.01). Groups with Sunflower oil in flushing diet had higher blood glucose levels than others (P<0.01). Blood sera concentrations of insulin and estrogen were higher in sunflower oil supplemented group than others (P<0.05). Fat supplementation of flushing diets resulted in lambs with greater birth weight (P<0.05). The number of offspring and twining birth was higher in the sunflower oil treatment (P<0.01). Results indicated that, using sunflower oil in flushing diet increased metabolites and hormones related to reproduction and subsequently improved offspring number and twining.

To evaluate capability of sonography for estimation of carcass traits of live animals in Afshari sheep a study was conducted using 97 male lambs of Afshari breeds. Lambs were at age of 11 month before slaughtering. Muscle thickness, loin muscle area and back fat thickness, between 12th and 13th ribs was measured using the ultrasound. Back fat and muscle thickness was also measured directly using a metal ruler in same area on the carcasses. Carcasses were stored at cold room for 24 hours and afterward were divided into two halves of left and right. The right side of carcasses dissected into neck, leg, thigh, tail and waste. Ultrasound measurement of longissimous muscle showed a high accuracy and highly correlated with carcass weight (0.84), arm (0.8), flank area (0.78) and thigh (0.74) muscles with bone, respectively. Ultrasound muscle depth and its direct measurement on carcass were highly correlated (0.87). But its correlation with weight of carcass components was less than those of muscle area. Correlation between fat depth measured by ultrasound and fat depth measured on the carcass was 0.7. Regression equations for prediction of carcass traits using ultrasound and carcass measurements were calculated. The results of this study showed that measurement of loin muscle area and back fat by ultrasound has relatively good accuracy and can be used for estimation of some carcass traits.

Relatively high cost of milk production appears the necessity and importance of producers and policy makers' attention in order to reduce the production cost. It would require full knowledge of the structure of production technology. The present study analyzed the production structure of milk-producing farms of Isfahan. To this end, the Translog cost function and derived cost share equations estimated in a system of equations by iterative seemingly unrelated regression using the theory of duality. The results showed that the milk production has increasing returns to scale. Magnitudes of own price elasticityof inputs also indicate that they are inelastic. However, the own price elasticity of animal feed is the smallest. Also, the cross elasticity of animal feed against the change of other input prices is lower than other ones. Finally, it is recommended that the milk-producing farms can increase milk production by increasing the amount of inputs proportionally. In other words, they can use advantages of increasing returns to scale in order to more economical production.