To investigate the nutritive value of egg and the possible use of waste eggs and spray-dried whole egg, as alternative protein source in neonatal calves, an experiment was done using twenty female and male Holstein calves. The treatments were: 1) milk without egg (control), 2) milk contain 7.5% raw egg, 3) milk containhng 7.5% raw egg and biotin (1 mg/kg), 4) milk contain, 7.5% spray-dried whole egg powder, in a 57/d feeding trial. Data were analyzed in a completely randomized design (CRD). The results showed that there were no significant differences between treatments on body weight (BW), average daily gains (ADG), dry mater (DM) intakes and feed conversion ratio (FCR) of calves. Digestibility of dry matter in control and milk containing 7.5% raw egg and biotin increased significantly. The concentration of cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were not significant difference versus treatment control. The Concentration of blood ferritin significantly increased by egg powder. There were no significant differences between treatments on IgG and total protein of blood calves. Results of experiment showed that feeding of calves with milk contain 7.5% egg, without negative effets on performance and blood parameters of calves.

The objective of this study was to determine the optimal herd life of dairy cows in North West of Iran based on data collected from nine large herds of three provinces (Ardabil, East Azerbaijan and West Azerbaijan) and to assess its affecting factors using data on costs and revenues in 2012 and by stochastic dynamic programming. Variables used to describe the state of cows included lactation number at 10 levels, production ability at 3 levels and reproductive performance at 4 levels. Markov chain was used to incorporate the probability for each level of factors in determining the status of a cow. The objective function was the expected net present value of a cow in a 10-years horizon and the optimization criterion was to maximize this function. Using dynamic programming the optimal combination of the state variables was realized and hence the optimum herd life of the cows was estimated to be 4.99 years. Examination of optimal objective function in different states revealed that increasing the production level and reducing the calving interval resulted in higher expected net present value of cows. The effect of changes in price of heifers, milk and discount rates on optimal herd life was examined and it was found that by increasing heifer price, lowering milk price and increasing the discount rate, the culling rate was decreased and optimal herd life was increased.

Object: Determination of vitamin A and Beta carotene status in Holestein cow.Design: Cross sectional study. Animals: A total of 342 blood and 371 liver samples from Holestein cows in both sexes and 5 age groups as <2, 2-3, 3-4, 4-5, 5< years. Procedure: Livels of vit. A as well as R carotene were determined in serum and liver by a spectrophotometer at wave length of 325 - and 453nm as follows: Levels of vitamin A in serum and liver =[(0.000017×figure of beta carotene)-(absorption levels at 325nm)]/(0.00182) Levels of β carotene In serum and liver = (absorption levels 453 nm)/ 0.00258 Hexane was used as a blank. Statistical analysis: Results were analyzed by ANOVA. Results: In this survey the levels of vitamin A and Beta carotene of serum and liver were 67.2 ± 3.1, 85.5 ± 4.0 µg/dl and 189.3 ± 3.0, 21.1 ± 1 µg/g respectively. Differences of liver vitamin A levels in 4 and 5 age groups and also between these two age groups and others were significant (P<0.001). In the meanwhile levels of liver vitamin A and those of liver and serum β carotene of females were significantly higher than of males. Effects of season alone and both of season and sex, season and age, age and sex combinations were different. Apart from vitamin A and β carotene the relationship among all the other variants of this survey were significant. Conclusion: On the basis of the results of this survey effects of nutrition and to some extent female and vitamin A and βcarotene were highly considerable but high Levels of liver vitamin A in winter were not explainable.

Collected semen with a good quality and quantity is essential for a bull for selected semen collection and preservation. This survey was carried out on a Friesian Holstein bull, kept in Northwestern breeding center of Iran. Although the bull had normal libido, the semen produced was reported to be azoospermic. Clinical examinations proved no testicular abnormality but the scrotal circumference was measured 27 centimetres which is less than the normal size of this breed (at least 30 centimetres). In histopathological studies, there was a decrease in semeniferous tubule's epithelium (sertoli and gonadal cells), Beside intratubules focal calcifications, fonnation of new connective tissue and vascularization was observed. All of these signs demonstrate an extensive degeneration in both testes.

Feeding unsaturated fatty acids sources in dairy cows is an strategy to improve animal health during postpartum period. The aim of this study was to investigate the effects of different sources of fatty acids on dry matter intake (DMI), milk production and composition and blood metabolites during the transition period in Holstein dairy cow. Multiparous pregnant Holstein cows (n=35) were selected (around 21 days before calving) and assigned randomly to one of the five experimental treatments including: 1) control (Source of palmitic acid), 2) CLA supplementation, 3) extruded linseed (LIN), 4) extruded linseed and CLA blend (LIN+CLA), 5) meal and calcium oil sesame. DMI and milk yield were recorded daily. Blood samples were collected at-21,-14,-7,-3, 0, 3, 7, 14 and 21 d relative to calving to determine plasma concentration of glucose, cholesterol, triglyceride, low density lipoprotein (LDL) and nonesterified fatty acid (NEFA). DMI, milk yield and composition, plasma concentrations of NEFA and triglyceride were not affected by treatments. During the postpartum period, plasma concentrations of glucose were greater in CLA treatment compared with control, LIN and LIN+CLA diets. Control treatment had the greatest plasma concentration of LDL. Cholesterol concentration of control treatment was higher at 7 and 14 d post calving compared with other treatments. In overall, feeding the unsaturated fatty acid improved concentration of blood metabolites, although they had no effect on milk performance.

In order to compare the effects of different weaning strategies on feed intake, structural growth measurement and health, blood metabolites and economic efficiency of young dairy calves, twenty four female Holstein calves were used. Calves after birth were randomly assigned into one of three weaning strategy as follow: 1) weaning based on feed intake, 2) weaning based on weight gain (30 kg weight gain compared to the birth weight), and 3) weaning based on age (at 90 days of age). Starter intake measurement and fecal scoring conducted daily. Calves were weighed weekly and blood samples were obtained on days 21, 42, 60 and 90 after birth. Results showed that there were significant differences among different weaning strategies on average weaning age and milk consumption (p<0. 05). All treatments had similar average daily weight gain, average daily feed intake, final weight and structural growth measurements. Calves weaned based on feed intake had lowest ruminal pH and N-NH3concentration and blood urea nitrogen on day 90 (p<0. 05). There were differences between groups on milk cost and total cost (milk + feed) and feed cost per kg of BW gain, so that Weaning based of feed intake compared to weaning based on weight and age saved up to 6000 and 3000 Rials per kg of body weight, respectively. Generally, similar growth and performance among different weaning strategies as well as reduction the cost of raising of calves indicated that calves weaning based on feed intake can be profitable approach.

Bovine leukosis virus (BLV) is a retrovirus that primarily affects lymphoid tissue of cattle. To determine the seroprevalence of Enzootic Bovine Leukosis Virus infection and its effects on some clinical, hematological and flow cytometric indications, this study was conducted on 197 Holstein cattle slaughtered in an abattoir in Tehran province. ELISA gp51 test of the obtained serums of the animals showed that the mean of infection rates was 22.3%. Age arrangement of the relative frequencies of the infection showed a significant correlation between EBLV infection and age increasing (0.001<p<0.005). There was a significant difference between the infection rates in cattle with any clinical problems or macroscopic pathological lesions and in apparently normal animals (0.001 <p<0.005). There weren't any significant correlation between EBLV infection and sex and body condition score. With omitting the animals with any clinical problems or macroscopic pathological lesions and stressed ones, because of probability of the secondary changes in hematological indications of them, seropositive cattle had higher total leukocyte counts (0.01<p<0.05) and 10wer Tlymphocyte (CD4+) percentage (0.01<p<0.05) than seronegative cattle. In addition there was a positive correlation between the number of B-Iymphocyte (CD21+) and total leukocyte counts and lymphocyte percentage in seropositive cattle. Results of this study depicted high seroprevalence rate of Enzootic Bovine Leukosis Virus infection in the surveyed animals and lower CD4+-cells percentage in seropositive cattle than seronegative ones.

The milk and fat production and some reproductive traits of Holestein cows in 6 dairy herds around Yazd (central region of Iran) using 11200 records from 550 cows were studied. The estimation of least square means of corrected (2X, 3050, ME) milk yield, fat production and fat percentage were 6270.30±48.20, 217.70±1.87 kg and 3.50±0.02 percent, respectively. Effects of herd, year and season on milk and fat yield were significant (p<0.01). Milk and fat production of cows, in fall season calving were more than other seasons (p<0.01). The estimation of least square means of calving interval (Cl), days open, dry period, days in milking and age at first calving (AFC) were 382.00±4.49, 103.00±5.12, 75.00±3.39, 307.00±3.72 days and 28.00±0.35 months, respectively. Effect of year on Cl and AFC was significant (p< 0.01). The results suggest that, autumn calving can be used as a strategy for increasing milk and fat production of Holestein cows in Yazd, in order to increase the economic efficiency of herds, AFC and Cl need to be improved.