نشریه پژوهش های علوم دامی
سال بیست و سوم شماره 2 (تابستان 1392)

Although Wood function is of great importance to studying lactation curves because of its coefficients with biological interpretation, it has not been used under a random regression models. The objective of this study was to investigate the possibility of fitting Wood function on the test day records of dairy cows under a random regression model. Data was consisted of 743,205 test day records in first lactation of 81,192 Holstein cows from 46 herds in Iran which have been collected during 1991 to 2008. Linear form of Wood function which was a polynomial of 3 has been used. Three forms of Legendre polynomial functions with third order for additive genetic effects were also applied to evaluate the results of Wood function. Heritability estimates for daily milk yield obtained by linear form of Wood function were higher than those obtained by Legendre functions in most days indicating its advantage for genetic evaluations. Correlation between breeding values of animals predicted by linear form of Wood function and Legendre functions was 90%. In conclusion, Wood function can be employed in random regression models causing exploitation its desired characteristics and the advantages of random regression models to explain the genetic variations of dairy cows’ lactation curve.

In this research, 30Ghezel and 31Mehraban post-weaned male lambs were used to study the effect of slaughter weight on carcass characters. The lambs of each breed were randomly assigned to predetermined slaughter weight groups of small (50 kg for Ghezel and 45 kg for Mehraban), medium (60 kg for Ghezel and 55 kg for Mehraban) and large (70 kg for Ghezel and 65 kg for Mehraban) Kg and were fattened as long as reached their assigned slaughter weight.All non-carcass fats and back fat thickness increased (P<0.05) with increasing slaughter weight. The mean of fat-tail weight increased (P<0.05) with increasing slaughter weight in the both breeds. In Mehraban lambs the fat and bone of carcass cuts increased (P<0.05) with increasing slaughter weight from medium to large but the meat of carcass cut did not. In Ghezel lambs the meat, fat and bone of carcass cuts increased (P<0.05) with increasing slaughter weight from medium to large. Based on the obtained results it can be concluded that Ghezel lambs can be fattened for weight of 70 kg, but slaughter weight of 55 kg seems to be an acceptable slaughter weight for Mehraban lambs.

An experiment was conducted to investigate the effects of different levels of feed restriction on performance and body temperature of broiler chickens under heat stress condition. A total number of 240 cockerels from Ross 308 commercial strain were used as a completely randomized design. Chickens were kept under heat stress condition (35±2 °C) for 4 hours a day from 7 to 21 days of age. Treatments were different levels of feed restriction (70, 80 and 90 percent of control bird) from 7 to 14 days of age and (80 and 90 percent of control bird) from 7 to 21 days of age. At 42 days of age no differences were found between treatments for feed intake, body weight gain and feed conversion rate but for 7 to 21 days of age feed intake and body weight gain were significantly lower in feed restricted birds, also in feed restricted birds till 21 days of age feed conversion was lower than control birds. Duodenum weight in birds under 80 percent feed restriction till 21 days of age was the lowest. Different levels of feed restriction under heat stress condition didn’t have any effect on length and ash percent of tibia. In comparison before and during heat stress uric acid and glucose levels were lower after heatstress. Whereas triglyceride and HDL were increased during heat stress. At 14 days of age, control group was shown the highest rectal temperature after exposure to heat stress. But during heat stress at 21 days of age the highestrectal temperature was observed in feed restriction birds till 14 days of age. Finally we concluded that feed restriction under heat stress conditions moreover its useful effects due to chicken’s compensatory growth, also causes a decrease in feed cost and almost adjustment of harmful impacts of heat stress.

Livestock husbandry in dry areas is facing scarcity and fluctuation of feed supply specially during dry seasons. At the same time use of halophytic plants such as Alhagi spp. could supply small ruminant requirements. The study was conducted to determine the effect of feeding diets containing Alhagi on the milk yield of Baloochi ewes and body weight gain of their lambs. Seventy-two adult Baloochi ewes (43.5±3.5 kg) in late gestation were randomly selected and distributed into three equal groups, 24 animals each. The selected ewes were fed with the dietary treatments for 2 month before the lambing date and continued until 60 days. The treatments include: 1) Alhagi 0%, wheat straw 65%, barley grain 20%; 2) Alhagi 40%, wheat straw 25%, barley grain 20%; 3) Alhagi 80%, barley grain 20%. Increasing Alhagi replacement in diet led to raise in lignin-cellulose materials. The dietary treatments had a significant effect on overall DMI of ewes (P<0.05). The ewes receiving diets without Alhagi (1338.25 gr) and containing 80% Alhagi (1323.50gr) had increased feed intake significantly (P<0.05) compared with animals fed with Alhagi 40 percent (1068.25gr). Also treatments had a significant effect (P<0.05) on DMI of ewes during the different physiological stages: late gestation and lactating. The ewes fed with Alhagi 80% showed higher milk production than those fed with 40% Alhaji foliage in diet. Means of daily milk production were 574.42, 499.01 and 642.99 g per ewe for the diets containing 0, 40 and 80 % Alhaji, respectively. The milk fat percent related to diet 0% Alhagi was higher than diet containing 80% Alhagi significantly (P<0.05) and milk protein percent was highest (P<0.05) for ewes fed with 0% Alhagi. Diets had no significant effect on milk lactose, SNF and TS percents. The treatments had no significant effect on birth weight. The highest weaning weight and growth rate of lambs was for ewes received diet 0% Alhagi and the lowest was for ewes fed diet 40% Alhagi (P<0.01). Feeding Alhagi browse with energy supplement to lactating Baloochi ewes did not present any significant problems on milk yield or growth rate of lambs and substituting Alhagi browse for cereal straw or alfalfa in diets of sheep and will reduce the cost of roughage component and also it will supply nutritive during periods with forage scarcity.

Zilpaterol (ZH) is a ß-adrenergic agonist which has been shown to improve feedlot performance in rumiunant. The aim of this study was to investigate the effects of alternative consume of dietary ZH on growth performance in Ross broiler chicks. Eighty 25 d-old Ross female broiler chicks were used in a 20 day feeding (four pens per treatment in a completely randomized design) Chicks were fed a corn and soybean meal based finishing diet and received ZH at level 0, 0.2, 0.25, 0.3 mg/kg of live body weight in a skip 2 days manner. Each bird was individually weighed on d 25, 48 of the experiment. On d 48, chickens were slaughtered and carcass data were collected. Data were analyzed using Proc GLM in SAS program. Supplemental ZH significantly improved feed efficiency compared with control group (P<0.05) and treatment that contained 0.25 ZH had best result (P<0.05). ZH increased final LBW of broiler chicken. But the effect of ZH on carcass weight and carcass yield was not significant. Consumption of Zilpaterol hydrochloride increase glucose plasma (P<0.05). Also Zilpaterol hydrochloride induced an increase in tissue protein (P<0.05). The result suggested that Zilpaterol hydrochloride as a ß-agonist improved growth performance in broiler chicken.

Honey production is correlated to some behavior‚ productive and morphological characteristic in honeybee colonies. In the other hand‚ fluctuation of these traits simultaneously can increase or decrease of honey production in colonies. Determining the correlated traits of honey production‚ can help the researchers and beekeepers to identify the best colonies with lower cost and during the fewer time. This research has tried to find the correlation between honey production and worker foraging behavior through different methods in 10th generation colonies of “Honey Breeding Project of Iran”. In the first method‚ in the sunny day and without wind in the hours between 11 and13‚while the hive entrance was closed‚ pictures were taken front of each hive. The pictures were taken at the same distances of hives‚ by a camera that was equipped with macro lens. Then the bees were counted in front of each colony or hive. In the second method‚ the number of bees that going out and return back to the hive also the numbers of returned foragers with pollen load were counted during 2 minutes in front of each hive entrance. Counting the foragers was done in the morning and afternoon of the same day for all of the colonies. The obtained data were compared through T-test analysis program in high and low production colonies and different times. The obtained data were showed the retuned bees (P<0.05) and returned bees with pollen load (P<0.05) in high production colonies were more than low production colonies (in both of methods). But the number of bees that were going out of colonies has not significant differentness. Our results showed that the number of foragers in the morning were more than afternoon in the some days (P<0.05). So the number of forager bees has positive correlation with honey production in honeybee colonies. Therefore‚ the number of foragers of colonies can help the beekeepers and researchers to select the best colonies in order to establish the next generations.

This study was conducted to determine the effects of nitrogen fertilizer and polyethylene glycol)PEG 6000) application on safflower forage and silage on their chemical composition, ruminal degradability parameters and in vitro gas production. Safflower forage was harvested in June 2010 at budding growth stage with 30 percent dry matter content from research farm of Birjand university agricultural college. Urea was used as forage’s N fertilizer (at rate of 300 kg N/ha) and PEG solution (with concentration of 30g/100 ml, solution 30% w/v) was used as silage’s additive. Chemical composition was determined in both safflower forage and silage but DM ruminal degradability and gas production were determined just in safflower silage. So there was 2 treatments in evaluation of forage chemical composition as: 1- forage fertilized with N, and 2- unfertilized forage, while 4 treatments were available in evaluation of safflower silage as: 1- silage of unfertilized forage and without polyethylene glycol additive, 2- silage of unfertilized forage and with polyethylene glycol additive, 3- silage of fertilized forage and without polyethylene glycol additive and 4- silage of fertilized forage and with polyethylene glycol additive. Forage N fertilizing caused to increase its CP content and took place a suitable fermentation trend in its silage. Also, silages of fertilized forages had higher ruminal and post-ruminal digestibilities. Adding PEG had no effect on digestibility and other determined parameters of experimental silages. The results of this study showed safflower N fertilized forage and its silage was of high nutritional value in ruminant feeding, especially at arid areas with saline soils which this plant is well adapted.

Hygienic behavior is important defense mechanism of honeybee colonies. This behavior protected the colonies against various pathogens such as bacteria, fungi and some parasites similar varroa mite. One of Hygienic behavior is consist of detecting of damaged or died brood, uncapping their cells and removing the broods. This study was carried out on 100 colonies of honeybee breeding project of Iran. Uncapping and removing and also some performance traits such as honey production, defense behavior and population size of honeybee colonies were evaluated in the spring and summer. Results showed considerable phenotypic variation of uncapping and removing in the honey bee colonies. 21 and 18 percent of colonies had desirable hygienic behavior in the first and second period of research. Results showed there are no significant correlation between defense behavior and hygienic behavior. Obtained results showed the removing have significant correlation with population size (P<0.05), honey production have significant correlation with uncapping (P<0.01) and removing behavior (P<0.05). Based on these results it seems the selection of hygienic colonies in honeybee breeding programs can make good progress in the future.

To study the effect of production season on probability of milk fat depression (MFD), a number of 938,047 test day records belonging to 108,077 first-parity Holstein cows belonging 427 herds and calved during 1995-2009 were used. Logistic generalized linear model using GLIMMIX procedure of SAS software was fit to the data. In the model, fixed effects of production season in four levels (spring, summer, autumn and winter), sperm type (internal and external) used for dam insemination, first calving age, herd production level, animal genotype (grade and pure Holstein), calving year, stage of lactation as well as random effect of animal’s sire were included. Based upon fat to protein ratio for each test day record and with respect to threshold point of -0.12, dependent variable was defined as a binary (zero code for lack of MFD and unit code for incidence of MFD) character. The results indicated that all factors included in the model (except sperm type) had significant effects on probability of MFD. Estimates of odds ratio (OR) for spring season was found to be 0.832, 0.835 and 1.248 relative to the summer, autumn and winter seasons, respectively, and for the summer season were 1.004 and 1.494 relative to the autumn and winter seasons, respectively, and for the autumn season was 1.493 relative to the winter season. MFD probability in the spring as compared to the summer and autumn seasons were lower by 16.8% and 16.5%, respectively while it was greater by 24.8% as compared to the winter season. MFD probability in summer season was greater than that of the autumn and winter seasons by 0.04% and 49.9%, respectively. OR estimate indicated that MFD probability was greater in the autumn season by 49.3% as compared to the winter season. With respect to a higher probability of MFD in summer season, more attention to roughage feeding is essential.

The effects of four dietary fat sources were studied on growth performance, bacterial community and pH values in digesta of small intestine and cecum of broiler chickens. A total of 240 one d-old male broiler chicks were randomly assigned to four experimental diets with 6 replicates per each. The four experimental diets were diet without fat (control diet), diet containing 6% beef tallow (BT), diet containing 6% sunflower oil (SO) and diet containing 6% fish oil (FO) and fed to chicks from 0-42 days of age. Our results showed that FO diets significantly increased weight gain of chicks compared to control or BT diets from 1 to 21 d of age (P=0.022). At the same age, the best feed conversion ratio was observed in chicks fed SO and FO diets as compared with chicks fed BT treatment (P=0.038). Body weight gain, feed intake and feed conversion ratio of birds were not significantly affected by dietary fat sources at the entire experimental period (1-42 d). The birds fed SO and FO diets, had higher counts of Lactobacillus spp. in small intestine and cecum digesta and lower counts of coliforms in cecal digesta as compared to birds fed BT diet (P<0.05). A significant decrease was also observed in pH of cecal digesta of birds fed FO diet (P=0.039) compared to those fed BT diet at 42 d of age. In conclusion, the dietary fats rich in polyunsaturated fatty acids can improve growth performance, intestinal microflora and pH value in broiler chicks as compared with the dietary fats rich in saturated fatty acids.

A set of in vitro experiments conducted to determine ruminal metabolism of fish oil fatty acids (Complete randomized block design), effects of fish oil on protozoa population, rumen parameters and nutrient digestibility (Complete randomized design). Also the effects of oil protection methods on these parameters were addressed. Extent of apparent fatty acid biohydrogenation was too far from accumulation of corresponding saturated fatty acids, which indicated incomplete biohydrogenation of fish oil fatty acids. Different biohydrogenation intermediates of 18, 20 and 22 carbon length was detected in incubation vessels and their contribution on apparent biohydrogenation was calculated. Protection of fish oil affected extent of ruminal fatty acid biohydrogenation and also production and accumulation of biohydrogenation intermediates. Unprotected oil and fatty acids had major effects on protozoa counts, VFA and ammonia nitrogen concentrations. Protection methods were resulted in increased concentration of VFA and cell wall digestibility and molar proportions of acetate. However, different protection methods with different oil concentration had different effects. Further experiments to fully describe effects of oil microencapsulation on biohydrogenation and also in vivo experiments are warranted.

The objective of this study was investigating the effect of monensin and vitamin E supplementation on nutrients degradability characteristics of diet with high content of oilseed using in situ technique. For this purpose two ruminal fistulated sheep were used. Experimental treatments were: a) treatment with 20% whole cottonseed without monensin and vitamin E supplementation, b) treatment with 20% whole cottonseed and 500 IU of vitamin E and c) treatment with 20% whole cottonseed and 24 mg of monensin/kg DM. The incubation times were 0, 2, 4, 6, 8, 12, 16, 24, 36, and 48 h. The obtained data was analyzed using SAS program as completely randomized design With ANOVA procedure. 2 h after incubation, the treatment with monensin had the highest DM disappearance among treatments (P<0.05). The treatment with monensin for 48 h ruminal incubation had the highest (71.17%) DM disappearance and treatment without additive had the lowest (50.51%) DM disappearance (P<0.05). Supplementing monensin and vitamin E to the diet with high level of oilseed increased DM, OM, CP, NDF and ADF digestibilies in rumen (P<0.05). The results indicate that monensin and vitamin E supplementation to diet with high level of cottonseed may improve ruminal function and cause increase in rumen nutrients degradabilies.

In the order to compare some growth and quantitative and qualitative carcass traits of crossbred and Ghezel lambs of Khalat-Pooshan research station 40 male lambs of the same age were used. Genetic groups were included the 7 heads of pure Ghezel lambs and the 7 heads Baluchi×Ghezel crossbred lambs, 7 heads Arkharmerinoos×Ghezel and the 10 heads Arkharmerinoos×Moghani and the 9 heads Baluchi×Moghani lambs. The lambs in 90 days of age were fattened for 110 days in 5 groups. In during of fattened period the weighting operation were doing after 18 hours hunger. Feeds remaining were weighted in close day. Finally feed conversion ratio was calculated according to dry matter intake. In finish five heads slaughtered of any genetic groups. The carcasses were transferred to freezing home in four centigrade for 24 hours. After the exit of carcasses of freezing home and recording the morphologic traits, segmentation of right side of carcasses of any animal were doing as (4276) standard of Iran. For analyze of traits the SAS 9.1 software was used and comparing of means were did of comparing the least square means. In this study genetic combination was significant on gigot width (B) and the weight of shoulder, femoral muscle, bone, kidney fat, mesenteric fat, dressing percentage, meat to fat percentage in 0.05 probability and significant on weights of hot carcass, cold carcass, hot fat tailed, flank and body fat in 0.01 probability.Total carcass fat of Iranian crossbred lambs and Ghezel breed was higher than Arkharmerinoos crossbred lambs, this result showed the pure performance of Iranian breeds. In comparing of meat to fat Ghezel breed and Baluchi×Moghani had pure performance to Arkharmerinoos crossbred lambs in meat to fat ratio Large fat tail size of Iranian crossbreed sheep’s is reason of this result.

This study was conducted to survey a laying parent stock performance and egg quality traits. A laying parent stock unit was selected at the age of 52 wk and data including hen and cockerel number, mortality percent, hen to cockerel ratio, egg production percent (hen day and hen housed production), non- settable egg number and settable egg (%) were recorded daily up to 72 wk of age before beginning of molting. For calculating hatchability (%), the data were obtained from hatchery unit. The collected data were divided to 6 experimental periods (28 days/period). At beginning of the study, the number of hen and cockerel were 30013 and 4144, respectively. The hen to cockerel ratio was 14. The percent of hen and cockerel mortality at experimental periods were 0.033 and 0.022, respectively. Hen day egg production (%) was lowered as compared to the recommended data in parent stock management guide (5.55 %). Generally, the analysis of the data showed that with increasing experimental periods (or the age of birds), the non-settable and settable egg numbers were increased and decreased, respectively. The settable egg (%) was significantly different from the recommended data in parent stock management guide. With increasing experimental periods, the hatchability was deceased. The hatchability (%) of this farm was lowered as compared to recommended data in parent stock management guide. The analyzing of concerned production traits of this farm revealed that production and nutritional management need more attention in this laying parent stock unit.

Chemical compositions of treated date palm fronds with Neurospora Sitophila were determined by proximate analysis and dry matter (DM), crude protein (CP) and natural detergent fiber (NDF) degradabilities were studied by using in situ technique. The data were analyzed as completely randomized design. Mean values of DM, Organic Matter (OM), CP, NDF, acid detergent fiber (ADF) and ash for untreated date palm fronds were 94, 89.62, 5.1, 78.98, 77.23 and 10.08 percent, and for treated date palm fronds were 92.16, 88.76, 10, 77.45, 75.80 and 11.23 percent, respectively. After processing, CP of date palm fronds was increased (P<0.05), whereas the percentages of DM, NDF and ADF were decreased (P<0.05). Physical characteristics such as water-holding capacity and soluble DM were decreased, however, soluble ash, specific gravity and bulk density were increased by processing (P<0.05). Effective degradability and nutritive value index (NVI) of DM and CP, and NDF degradability for treated date palm fronds were higher than untreated (P<0.05). Generally, processing of date palm fronds by Neurospora Sitophila increased CP, effective degradability and NVI values and its physical characteristics was improved. Therefore, processed date palm fronds can be used as a valuable feed for animal consumption.