نشریه پژوهش های علوم دامی
سال بیست و یکم شماره 2 (پاییز 1390)

Native chicken breeds are national investment and conservation of these populations is very important from biodiversity aspects. Studying mitochondrial genome in one breed and comparing it with other breeds can give useful information about genetic diversity in that population. This study carried out for determination of mitochondrial HVS-I sequence in Marandi native chicken. DNA was extracted from 15 random birds and HVS-I region was amplified using specific primers and then sequenced after cloning. From 15 primary sequences, 10 were sequenced properly and one consensus sequence was obtained. In studied population 6 haplotypes were observed and submitted to gene bank (NCBI) under accession numbers of GU481096-GU481104. The phylogenic tree was drawn with consensus sequence of Mazandarani breed and other similar sequences of different chicken breeds obtained from gene bank. In the phylogenic tree, the Marandi breed was clustered with Azarbayjan native, white Leghorn, barred plymoth Rock, Silky and Sonerati breeds. Then, it can be concluded that Marandi breed has genetic similarities with some commercially productive chicken breeds.

This study was conducted to determine the chemical composition and nutritive value of barely grain (Hordum Vulgar)، common vetch (Vicia Sativa) and bitter vetch (Vicia Ervilia) in both raw and roasted forms by in vivo and in vitro techniques. Sixteen Mehraban male sheep (in vivo) and tree fistulated Mehraban male sheep (in vitro) were used in this study. Roasting has been done in 120°C، for 10 minutes by gas- burning heaters. The effect of dry roasting on the barley grains، vetch and bitter vetch chemical composition did not have shown significant difference except for DM. Nutrients digestibility of dry roasted grains was determined by in vivo technique. There was significant difference between almost nutrients digestive coefficients except for DM and OM (P < 0. 05). In vitro DM and OM digestibility had no significant difference between raw and roasted grains. The method of the digestibility determination had significant effect on dry matter digestibility but organic matter digestibility was not affected by two methods. Correlation coefficients between In vivo and In vitro technique for DM and OM respectively for barley were 92 and 90، for vetch 95 and 85 and for bitter vetch 97 and 93 respectively that confirm adequate and sufficient accuracy in performance of digestibility experiments. Thus we can use the in vitro method for feed evaluation، because it is quick، and simple.

The objective of this study was to determine the digestion and gas production potential of sodium hydroxide treated cottonseed hulls using in situ and in vitro procedures. Cottonseed hulls were treated using 2 and 4 percent solutions of sodium hydroxide and then kept for 0.5 and 48 h. For in situ procedure, 5 g of each sample was weighed into a polyester bag and incubated in the rumen of three ruminally fistulated sheep. After each time of incubation, bags were removed and rinsed with cold tap water. The residual of dry matter and neutral detergent fiber was determined. For the gas production technique (in vitro), approximately 0.3 g of each sample was placed in a 100 ml glass syringes then incubated into 40 ml of buffered rumen fluid (ratio of buffer to rumen fluid was 2:1). The amount of produced gas in each time of incubation in each syringe was accounted for determination of gas production parameters. Results of the in situ technique revealed that alkali treating of cottonseed hulls by a 4 percent solution for 0.5 and 48 h and a 2 percent solution for 48 h caused to a significant increase of the quickly degradable fraction (a) of dry matter (0.057, 0.090 and 0.080, respectively) and neutral detergent fiber (0.076, 0.105 and 0.056, respectively). Alkali treating of cottonseed hulls by a 2 percent solution for 0.5 and 48 h significantly (P<0.05) increased the slowly degradable fraction (b) and fractional constant rate (c) of neutral detergent fiber (0.673 and 0.887, respectively). Gas production parameters of cottonseed hulls did not alter when treated with different sodium hydroxide solutions.

Thirty Holstein calves were used to evaluate the effect of starting age for alfalfa feeding on feed intake، weight gain، feed efficiency، blood and rumen metabolites concentration، and weaning age. Average birth weight of the calves was 40. 6 ± 0. 77 Kg. The experimental diets were 1- diet containing starter concentrate، 2- diet containing starter concentrate + dry alfalfa (from the first day of the experiment) and 3- diet containing starter concentrate + dry alfalfa (from the day 21 of the experiment). All experimental diets were formulated to have the same levels of energy and crude protein. During the experiment، calves were fed with raw milk based on 10 % of their body weight and they were taken out three weeks after weaning. Experiment data were analyzed based upon a completely randomized design with three treatments and ten replicates per each treatment. The results showed that average daily feed intake was significantly (P<0. 05) greater for calves fed diets 2 and 3 than that of diet 1 for pre- and post weaning periods as well as the whole period of the experiment. Calves fed diet 2 had significantly (P<0. 05) greater average daily gain than diet 1 for pre-weaning and whole period of the experiment but no significant difference was found between diets for post-weaning period. Average weaning age for calves fed diet 2 was found to be significantly (P<0. 05) lower than the calves fed diet 1. The results of this study showed that the feeding alfalfa hay to calves from the first week after birth improved feed intake and daily gain and reduced weaning age.

Ovarian cysts are follicle-like structures with 2. 5 cm in diameter that persist at least for 10 days on one or both ovaries in the absence of corpus luteum. In order to investigation of estradiol 17-β، progesterone and blood urea nitrogen in cystic cows، 30 lactating Holstein cows (15 cystic and 15 normal cows) were used. Estradiol 17-β and progesterone were measured by chemilominecense method and blood urea nitrogen was measured using spectrophotometer. The results showed that the concentrations of estradiol 17-β and blood urea nitrogen (BUN) in cystic cows were significantly higher (P<0. 05) and glucose levels lower than the normal cows (P<0. 05). Milk yield had significantly effect on BUN levels (P<0. 05). The levels of estradiol 17-β in multiparous cystic cows were significantly higher than primiparous and multifarious normal cows (P<0. 05). Although mean of progesterone concentrations was lower in control group than cystic cows، there was no significantly difference between those groups (P=0. 06). This study showed that increasing of concentration of estradiol 17-β and blood urea nitrogen and decreasing blood progesterone can be used as sign of cystic ovaries in cow.

The objective of this study was to determine of chemical composition، true digestibility of amino acid (TDAA) and true metabolizable energy corrected to zero nitrogen balance (TMEn) of three poultry by-product meals (PBM). Three PBM were obtained from Tabriz، Mahabad and Urmia commercial slaughter plants. TMEn and TDAA of PBM samples were determined in 16 adult cecectomized broiler roosters with completely randomized design. Four roosters were assigned to each treatment and four roosters were deprived of feed throughout the experimental period to measure endogenous excretion of energy، N، and AA. The mean levels of nutrients (percentage) in the meals for CP، EE and ash were 56. 84±0. 42، 21. 57±0. 48 and 7. 62±0. 17، respectively. TMEn and TDAA were significant differences among meals (P< 0. 05) and mean of TMEn for all samples were 3528 (kcal/kg). TMEn for Tabriz sample was greatest and for Urmia sample was lowest (P< 0. 05). Mean of TDAA for Tabriz sample (81. 56%) was higher than Mahabad (67. 71%) and Urmia (66. 9%) samples (P< 0. 05). However، digestible amino acid was greatest for Tabriz sample among the PBM. The results of this study indicated that the nutritive value of Tabriz PBM was higher than that of Urmia and Mahabad meals.

The objective of this study was to investigate the effects of probiotic in the midlactation of high yielding (47. 46 ± 6. 16 kg/d) dairy cows. This study was conducted by 56 lactating multiparous Holstein cows (96. 87 ± 32. 15 d in milk) in a randomized complete design with two treatments (probiotic and control). The program of using probiotic included: first period was from day 1 to 10 which each cow consumed 56 g of an combination named P-1 (priority one) /day، second period was from day 11 to 40 which each cow consumed 28 g P-One and 28 g of a combination named DCP (priority DCP) /day. Also، for similarity with commercial production، 300 mg/cow/d of monensin was used in control ration. Diets were fed grouping ad-libitum as total mixed ration with a concentrate to forage ratio of 64. 8:35. 2. These additives did not affect fiber and crude protein digestibility. Feeding probiotic increased propionate percentage (P<0. 05) and tended to decrease acetate: propionate ratio (P<0. 10). But rumen pH was not affected by treatments. Milk fat production was increased when probiotic was used (P<0. 05) but milk production and other milk components were unaffected by treatment. Under the conditions of this study، supplementing midlactation high producing cows with probiotic may improved rumen fermentation and some production parameters and can be replaced with monensin as feed additive.

Seasonality has been a major research area in economics for several decades. In our country there are only a few studies in this issue. This paper discusses about seasonal unit root tests and introduces HEGY as one of the most important unit root tests، and applies it for the broiler price in the East Azerbaijan، West Azerbaijan، Ardebil،Tehran and Zanjan. The results indicate that the price series have a seasonal unit root at biannual frequency، beside a common unit root at zero frequency، Therefore the price series exhibit seasonality.

An experiment was carried out to evaluate total mixed ration (TMR) physical form on some characteristics of rumen fermentation، milk yield and its components in lactating dairy cows. Three Brown Swiss dairy cows (average milk yield of 22 kg/d and 200±20 days in milk)، rumen-fistulated، were used in a Latin Square Design 3×3 with three diets as treatments. The experimental diets were: 1. TMR with mash concentrate، 2. TMR with pellet concentrate and 3. TMR with cubic form. The experimental diets were fed twice daily. Each experimental period was lasted 21 days، that allocated first 14 days for adaptation and next 7 days sampling practices، respectively. Samples were taken from milk، feed intake، feed residual and rumen fluid. Total time of chewing activity (including eating and rumination time) was measured for only one day during each period. The results indicated that consumption of DM، OM CP and NDF، milk yield، milk protein and lactose yield and percentage، rumen pH were not significantly affected by the experimental diets. However، the average time of eating and rumination feed intake over 24 hours as well as milk fat percentage and rumen N- NH3، were different significantly (P<0. 05) among the experimental diets. It seems that a decrease in the feed particle size of cubic processing is accompanying with decreasing chewing activity and milk fat percentage، but no adverse effect was revealed on dry matter intake، milk yield and its components.

In this study، nutritional values of lemon and orange pulps treated by Saccharomyces cerevisiae were investigated. Samples were analyzed for their chemical composition. Digestion coefficients of dry matter (DM) and organic matter (OM) were determined by an in vitro procedure. In situ degradability of dry matter، crude protein and NDF were also determined. The data were analyzed as completely randomized design. Mean values of the chemical analysis for crude protein، ash، organic matter، NDF and ADF for untreated lemon pulp were 8. 36، 6. 59، 93. 41، 18. 23 and 14. 45; for treated lemon pulp 14. 31، 18. 87، 81. 12، 28. 47 and 24. 36; for untreated orange pulp 8. 03،. 73، 96. 3، 17. 17 and 15. 38; and for treated orange pulp 16. 5، 6. 03، 93. 97، 26. 77 and 24. 63، respectively. The differences of chemical compositions of treated and untreated citrus pulp samples were significantly (P<0. 05). Digestible organic matter in dry matter and metabolisable energy for the lemon pulp were decreased (P<0. 05) by treatment. NDF degradability coefficient of lemonh pulp at different outflow rates (2%، 5% and 8%/h) was decreased significantly (P<0. 05) in treated citrus pulp. In conclusion، treating citrus pulp with Saccharomyces cerevisiae increased percentage of CP and NDF for citrus pulp، and increased NDF degradability for lemon pulp.

In other to evaluate the effect of different levels of Nanozeolite (NZ) to reduce aflatoxicocity in broilers، an experiment was conducted in a completely randomized design with 336 male Ross broilers with six dietary treatments and four replicates. Dietary treatments were a control corn-soy diet without aflatoxin (AF) and five other contaminated diets to 0. 5 ppm AF containing different levels of NZ (zero، 0. 25. 0. 5، 0. 75 and 1 percent). Birds were fed AF contaminated diet without NZ had significantly lower body weight gain and higher feed conversion ratio than the other dietary treatments (P<0. 05). Significant lower feed intake was found in broilers fed AF contaminated diet without NZ as compared to control diet during grower as well as whole periods of the experiment (P<0. 05). The utilization of NZ in broilers diets led to reduce of AF adverse effects on their performance. Feeding broiler diets by AF contaminated diet without NZ led to significant reduction of carcass yields as compared to control diet (P<0. 05). Broilers fed AF contaminated diet without NZ had significantly lower total protein، cholesterol، albumin and triglyceride serum concentrations as compared to control diet (P<0. 05). Adding NZ to AF contaminated diets led to increase these blood parameters. Although experimental treatments had no significant effect on total bacteria and lactobacillus populations، but adding NZ to contaminated diets without NZ led to decrease of total bacteria population and increased of lactobacillus population. Dietary treatments containing NZ had significantly lower coliform bacteria population than AF contaminated diet without NZ (P<0. 05).

The objective of this study was to determine the effect of various levels of precipitated microcrystaltic waste of Mashhad power plant (PMW) on egg production، egg weight، feed conversion ratio (FCR)، egg specific gravity and egg shell quality. Three hundred and fifteen laying hens (83 weeks age) were used in an experiment by employing a complete block randomized design for 12 weeks to test seven diets with 5 replicates and 9 birds in each. The levels of 0، 16. 6، 33. 4، 50، 66. 6، 83. 4 or 100% PMW were substituted with dietary CaCo3. Daily egg production was recorded، whereas egg weight and feed consumption were recorded once 28 day during. Two eggs from each replicate were used to measured egg components once 28 during. Hens fed diets supplemented with levels higher than 3. 34% PMW had lower hen-day egg production and egg mass and higher FCR than those fed control diet during the whole experimental period. Hens fed diets containing 8. 34 and 10% PMW had lower feed intake than those fed diets supplemented with 0، 1. 66 and 3. 34%. Hens had diets supplemented with higher than 3. 34% PMW produced lower shell weight and thickness than those fed control diet during the experiment. This study revealed that this PMW at the levels greater than 3. 34% of laying hen''s diet may negatively influence egg production or shell quality and decrease the feed intake.

The 18 multiparous close-up Holstein dairy cows averaging BW 791. 1 kg in 23 d before expected calving date were assigned in a completely randomized design (n = 6) to study the effects of different levels of effective neutral detergent fiber (peNDF) on feed intake and nutrients digestibility in close-up and performance in the subsequent lactation. The effective neutral detergent fiber was considered as high 30. 40 (H)، moderate 27. 38 (M) and low 24. 61% (L). These changes were induced by alfalfa، corn silage and barely grain alterations in diets. All the cows were fed the same diet after parturition. Total rumination time was 473، 443 and 408 min/d for treatments H، M and L، respectively (P < 0. 03). Pre-calving DMI was 12. 07، 14. 29 and 12. 89 kg/d، (P < 0. 0007)، and post-calving DMI was 17. 41، 19. 03 and 18. 72 for treatments H، M and L، respectively (P < 0. 0001). Milk yield (P < 0. 09) and milk protein yield (P < 0. 07) were tended to rise with decreasing the peNDF. Total chewing activity negatively affected by decreasing the peNDF content in the diet. The results of the present study indicated that decreasing the peNDF in close-up diets have potential to increased DMI in both pre and post calving. We conclude that although the strategy of decreasing peNDF content of the close-up diets increases DMI and had potential to improve energy balance in dairy cows; the severe decrease of peNDF in close-up diets could negatively affect rumination time that possibly could have negative effects on cow health.

In order to investigate the effect of genetic markers in genetic improvement of domestic fowl، seven breeding programs were simulated. In first breeding program called base program، phenotypic information of traits was only used. In this program، aggregative genotype equation consisted of body weight at 8 weeks of age، egg weight and egg number and selection index consisted of traits in aggregative genotype together with two other tarits including body weight at 12 weeks of age and age at sexual maturity. In other programs called marker assisted programs، QTL information that described 5، 10، 20، 30، 40 and 50% of genetic variation of egg number were also included in selection index. Based on obtained results، in program that QTL described 5% of genetic variance، economic response was improved by 3. 37% compared to base program. Economic response in program that QTL described 50% of genetic variance was also improved by 14. 28% compared to base program. Rate of inbreeding was decreased from 0. 69% in base program to 0. 50% in program that QTL described 50% of genetic variance in each generation. The results of present study showed that QTL information، even with 5% description of genetic variance، effectively can be used in genetic improvement of domestic fowl.