مجله تولیدات دامی
سال بیست و چهارم شماره 4 (زمستان 1401)

The aim of this study was to estimate the economic values for residual feed intake and some production and performance traits in Iranian Holstein dairy cow. For this purpose, trait by trait or multiple traits of bio-economic modeling along with production and economic data were used. These data were collected from seven large herds of dairy cows in 2020. The economic values of the residual feed intake was calculated in four different age groups. The diets of different groups were formulated using CNCPS software. Index economic weights (multiplication of the economic values by discounted genetic expressions, in Rial and one cow per year) on average at the level of the studied farms were estimated to be IRR 14280 per kg of milk yield; IRR 291060 per kg of fat yield; IRR 232260 per kg of protein yield; IRR - 790860 per kg of residual feed intake; IRR 702588 per month of longevity and IRR- 113820 per day of days open. The sensitivity analysis showed that the price of concentrate ingredients has a greater effect on the economic value of the residual feed intake than of forage ingredients. In the genetic- economic analysis, the milk production with a relative emphasis of 50 percent was the most important trait in the breeding of Iranian dairy cows, while the relative emphasis on feed efficiency was only about 5 percent. The results of this research provide valuable information for economic values of traits that can be used to complete the national selection index and cost-benefit analysis.

The objective of this study was to compare growth performance, birth and weaning body weights, and survivability between purebred Balouchi (n=53) and crossbred Balouchi×Romanov (n=114) lambs. In addition, carcass characteristics (n=24) were determined. Balouchi ewes were inseminated with Romanov semen to produce crossbred lambs. All experimental lambs were weaned at 77 d of age and slaughtered at 10 months of age. Birth body weight of the purebred Balouchi lambs was significantly greater than for the crossbred lambs (3.75 vs. 3.56 kg, P<0.01). However, weaning body weight and average daily gain from birth until weaning and slaughter were greater (P<0.05) for the crossbred lambs than for the purebred lambs. Slaughter body weight at 10-month age were not different brtween the tow groups  (P=0.08). Litter size was also increased by crossbreeding and using hormone (1.13 vs. 1.00), but lamb survivability was not different between the two groups. The fat yield decreased with crossbreeding. Crossbreeding increased (P<0.05) the weights of testis, liver, heart, and lung. It is concluded that crossbreeding Balouchi ewes with Romanov semen resulted in improved litter size, weaning and slaughter body weights, average daily gains from birth until weaning and slaughter, and carcass characteristics without affecting lamb survivability. Therefore, crossbreeding can be a profitable strategy to increase lamb (meat) production in Balouchi sheep.

The effect of feeding essential oil of Pistacia Atlantica Kurdica gum during the suckling period on pre and post-weaning growth performance of Sanjabi male lambs using 30 male lambs from an estrus synchronized flock of ewes was carried out, in the form of a completely randomized design with 3 treatments and 10 replications. The lambs were divided into three groups three days after birth. The first group received no essential oil, and the second and the third groups received a daily dose of 0.8 and 1.6 ml until weaning by a drenching syringe, respectively. Lambs were weaned at 100 days of age and were raised for 10 weeks with the other herd lambs until 170 days of age. Feeding the essential oil increased weaning weight and post-weaning daily weight gain. The blood glucose of lambs during the suckling or post-waning period did not change due to feeding the essential oil. Lambs received the essential oil and had lower blood cholesterol, triglyceride, total protein, and higher urea and albumin to globulin ratio. Feeding the essential oil reduced blood malondialdehyde levels but increasing the level of the essential oil did not further decrease this metabolite. The results showed that the essential oil as a new feed additive has a good potential to improve the pre and post-weaning performance of lambs when fed during the suckling period. Since, increasing the level of the essential oil resulted in no additional improvement in the performance of lambs therefore, a daily dose of 0.8 ml is recommended.

The effect of using different levels of olive cake on production, milk composition and antioxidant atatus of dromedary camels, an experiment using 9 Turkmen dromedary camels with milk production of 5 ± 0.7 kg/day and average weight of 500 ± 30 kg a 3 three-week periods (14 days of adaptation and 7 days of sampling) was investigated in the form of a change over design with 3 treatments and 9 replications. The experimental treatments were included: 1- control group, 2- treatment containing 15 percent olive cake and 3- treatment containing 30 percent olive cake. Feed intake and milk production were not affected by experimental treatments. Milk fat percent a nd yield and milk protein percent (2.5, 0.11 kg and 2.66, respectively) decreased due to use of olive cake in the diet (P<0.05). There was no difference in the concentration of most of fatty acids and the ratio of omega-6 to omega-3 fatty acids in the milk of camels fed experimental diets, but concentration of palmitic acid in camels that consumed 30 percent olive cake was lower than control group (P<0.05). According to the results of this research, the use of olive cake (in the level of 30 percent of ration DM) in camel feeding, may have positive effects on increasing the nutritional value of dairy products especially in arid and semi-arid areas.

The effect of chick initial body weight and dietary nutrients density on growth performance and immune response were investigated using 360 Ross 308 one-day-old straight run chicks (mixed sex) in a completely randomized design with 2×3 factorial arrangement of treatments, four replicates and 15 birds per replicate. The initial body weight of chicks was grouped as 42±1 g (standard weight); 38±1 g (light weight; 10% under standard weight); 46±1 g (heavy weight; 10% over standard weight) while the nutrients density of the diet was either 5% lower than the nutritional recommendation of Ross 308 (typical commercial diet in Iran), or as recommended by Ross 308 manual (high-density diet). Chickens fed the high-density diet had higher daily weight gain and lower conversion ratio than chickens fed the typical diets (P<0.05). The effect of dietary density and initial body weight of chicks on carcass components and weight of internal organs were not significant except for heart. Broilers fed the high-density diet and heavy weight had higher antibody titers to sheep red blood cell (P<0.05). Light chicks fed the high-density diets had greater total anti sheep red blood cell and immunoglobulin G titers than light chicks fed the typical diets (P<0.05). Results indicate that feeding light chicks with high-density diets increases their growth rate compared to the chicks with standard or heavy weights. Moreover, feeding diets with a high density of nutrients to light chicks can improve immune responses.

This research was carried out to evaluate the effect of sunflower seed meal fermented with Aspergillus niger and Saccharomyces cerevisiae on performance, nutrient digestibility, immune response, some blood parameters in 200 male Ross 308 broiler chicks in a completely randomized design. with five treatments. Experimental treatments were: 1- Diet containing sunflower seed meal fermented by Aspergillus niger 2- Diet containing sunflower seed meal fermented by Saccharomyces cerevisiae 3- Diet containing sunflower seed meal fermented by both Aspergillus niger and Aspergillus niger 4- Diet containing sunflower seed meal without processing 5-Control diet based on corn and soybean meal. Feed intake in control and treatment 1 were higher than the other treatments in starter and finisher periods of the experiment (P<0.05). Daily Feed intake in control group was higher than the other treatments in whole period of the experiment (P<0.05). Daily weight gain in control and treatment 1 were higher than the other group in starter and grower periods of the experiment (P<0.05). Feed conversion ratio in treatment 1 was better in finisher phase. In whole period of the experiment, feed conversion ratio in control and treatment 1 was better than the other treatments (P<0.05). Dry matter, crude protein, crude fat digestibility in the control group was higher than the other treatments (P<0.05). In conclusion, inclusion of sunflower seed meal fermented with Aspergillus niger, in broiler diet showed similar feed conversion ratio in compared to control group in whole period of the experiment and also lowered abdominal fat percentage.

The aim of the present study was to compare sponge and cider with two different brands in estrous synchronicity, vaginal health and off-breeding performance in Moghani ewes. For this purpose, 120 ewes of Moghani breed were selected and randomly divided into four experimental groups. Ewes in the first and second groups, using sponge Sponjavet and CIDER Eazi breed (as valid and common brands) for 12 days, respectively, and the third and fourth groups, respectively, using sponge Fluorojest and CIDER Progest (as New brands made jointly by Iran and China) were treated for 12 days. Ewes in all groups received 400 IU units of eCG at the time of sponge and cider harvest. The rate of vaginal mucosal discharge and adhesion in sponge was higher than cider (P< 0.01). However, there was no significant difference between reproduction and progesterone concentrations between CIDER and sponge as well as brands of these two tools.Therefore, due to lower price and similar efficiency, Sponge Fluorojest and CIDER Progest can be considered as an appropriate alternative to common commercial sponge and CIDER..