Review- This paper intended to review the lameness in dairy cattle. But it was necessary to have an overview about the hoof anatomical structure, it's growth and overgrowth properties. Most common causes of lameness such as laminitis and its different clinical form or presentation such as sole ulcers, toe ulcers, white line disorders, sole and white line hemorrhages have been reviewed and discussed. The prevention of laminitis and the major factors involved in damaging the corium in dairy cattle which have been subdivided into the headings of calving, diet, excess standing and general management are discussed in detail.

The objective of this study was to evaluate the effect of supplementing close-up diets with rumen undegradable protein on serum metabolites and the incidence of health disorders of Holstein dairy cows, during the hot season. Eighty-eight multiparous Holstein dairy cows were randomly assigned to 1 of 2 treatment groups: low crude protein (14.3% CP; 14CP) and high crude protein (17.1% CP; 17CP) diets. Blood samples were collected weekly from d -30 up to calving and then at 0, 5, 14, and 21 days after calving, for serum metabolites determination.  Cows fed the 17CP diet had higher serum concentrations of albumin, blood urea nitogen, and Mg than 14CP cows during the close-up period. In postpartum, the 17CP cows had higher serum albumin and creatinine and lower free fatty acid, BHB, and glucose concentrations than the 14CP cows. The risk to developing subclinical ketosis (SCK), metritis and endometritis were higher for the 14CP cows than the 17CP cows. Overall, feeding high rumen undegradable protein diet to close-up cows during the hot season increased serum creatinine concentrations and lowered the incidence of SCK and metritis and endometritis postpartum.

Objective: Haemophilus somnus can be involved of bovine genital system with reproductive problem and it could be isolated from reproductive organs of pregnant and non-pregnant healthy cows.Design: Prospective study.Animals: 226 Holstein dairy cows.Procedure: Cows were examined into the 3 groups: 1) Treatment group which was included 103 cows with reproductive diseases. 2) 66 pregnant cows. 3) 57 non-pregnant I healthy cows. Bacteriological samples were obtained from uterine, cervix and vagina in treatment and non-pregnant II healthy cows. However, samples from pregnant cows were obtained from cervix and vagina.Statistical analysis: Chi-square test.Results: Haemophilus somnus was isolated from 6(5.82%), 1(1.52%) and 10(17.52%) from treatment, pregnant and nonpregnant group, respectively. In this study, the highest infectious rate (3.88%) was in treatment group included the uterine tissue. Vaginal infection in non-pregnant group was; significantly different from the pregnant and treatment groups (P< 0.025). There were differences between warm and cold seasons of the year in respected to prevalence of the bacteria in the genital system (P< 0.05).Conclusion: Haemophilus somnus was isolated from 17 (7.53%) out of126 dairy cows. Cows with reproductive diseases were infected by haemophilus somnus and these bacteria may be the origin of the problems. Haemophilus somnus was isolated from healthy pregnant and non-pregnant cows.

Introduction: Secondary sex ratio (SSR) is the proportion of males to females at birth. It has been shown in many different mammalian species, many factors are associated with SSR. Changes in secondary sex ratio in dairy cows is considered economically important and the ability to change it could affect the revenues and profitability of a dairy farm. Thus, sperm or embryo sexing techniques in recent years has attracted more attention. Most breed of dairy cattle are more likely to have female calf is born to use them as replacement heifers and in order to maintain their productive herd number. On the contrary, when the goal is the production of meat, bull calves due to higher growth rates and production efficiency, are more convenient and more economically efficient. The aim of present study was to investigate some key factors affecting SSR in Iranian Holstein cows.According to Fisher, the sex ratio in the population under the control of natural selection is not always the same. There is overwhelming evidence to support the theory that shows Fisher Primary and secondary sex ratio sex ratio can deviate from this balance and natural selection caused a change in this ratio can be in certain circumstances. For example, the secondary sex ratio of 52: 48 has been reported in dairy cows. Studies on mammalian species suggest that several factors, including latitude of the location, the dominant regional climate model, time and frequency of mating to ovulation, diet, age of parents, physical score, breed and produced eggs from ovarian left or right can have a significant effect on the secondary sex ratio. Weather conditions may modify the internal environment and the effect on physiological mechanisms or through the impact on the frequency and type of foods available to parents, the secondary sex ratio is impressive. The impact on the quantity and quality of parent's access to food sources in many species of mammals, the sex ratio has been fixed.Previous reports have shown that high environmental temperature and higher rates of evaporation from a week to a month before conception secondary sex ratio was increased.Materials and method: The demographic, production and reproduction data of six large dairy farms between years 1375 and 1389 were used. The rolling average of 305 d fat corrected milk yield was 8145 kg with a range of 7578 to 8670 Kg. Breeding Center of Iran and the herds covered by the registration and recording them on a regular basis carried out by experts dairy cooperatives. The flocks were in the area northeast of the country.Production data (date corrected milk production and the cumulative production by 60 and 305 days of lactation), reproductive data (such as calving year, calving season, type of birth, sex of calf, the latest information on AI, days open), and details the possible removal of the flock or death were recorded. Data were collected from flocks before the analysis was re-verification. Used by sperm, sperm into four groups: Iranian, Canadian, American and other countries (including sperm taken from European countries) groups. The data were analyzed using multivariate logistic regression model.Statistics 0/05 was used to ensure meaningful results.Results and discussion: Results showed that the ratio of males to females was 53 to 47. Origin of the sires (including Iranian, American, or Canadian) had no impact on secondary sex ratio. Type of calving (eutocia vs.non-eutocia calving including dystocia and still birth) had significant impact on SSR (P<0.05). SSR was not effected by calving year. Season of calving, days open, parity, and the corrected 305 d milk yield also had no impact on SSR while the interaction of parity and type of calving was significant (P<0.05).Conclusion: In conclusion, the results of this study shows that type of calving only had a significant effect of SSR.

BACKGROUND: Postpartum anestrus is a major problem in primiparous dairy cows.OBJECTIVES: The objective of this study was to investigate postpartum ovarian activity in primiparous Holstein dairy cows.METHODS: Seven primiparous Holstein dairy cows were monitored for ovarian activity using a combination of ultrasound examination and alteration in progesterone concentrations. Daily blood sampling and ultrasound examination were conducted starting from day 6 until the third ovulation postpartum.RESULTS: First wave dominant follicles (³10 mm in diameter) were detected on day 11.5±1.48 postpartum. This follicle did not ovulate in any of the experimental cows. Moreover, none of the cows ovulated within 20 days postpartum. There was no difference in the follicular growth rate and the diameter of ovulatory follicles between the first, the second and the third ovulations postpartum (p>0.05). Interval from calving to the first postpartum ovulation was 48.1±6.89 days. Mean diameter of corpus luteum and progesterone concentrations of the first cycle (18.8±0.94 mm and 2.0±0.24 ng/mL) were significantly less than those of the second cycle (24.0±0.89 mm and 3.6±0.36 ng/mL; p<0.05).CONCLUSIONS: In conclusion, increased interval from parturition to the first ovulation is not due to the delayed or lack of the first wave dominant follicle formation after parturition; but is due to the regression of this follicle.

Injuries of the birth canal in cows (perineal lacerations, fistula…) cause significant economic loss in dairy herds. These injuries usually are associated with obstetric trauma during labor. Third degree perineal lacerations and fistula formation usually happen because of dystocia, improper repairs, abscesses and forced extractions and lead to fecal contamination of the birth canal and reduced fertility. The main reason for the birth canal and external part of the reproductive tract surgery is to restore fertility of the animal and repair the injuries associated with dystocia. In this review the causes, management, and treatment of these disorders by emphasizing on the importance of birth canal injuries in cows were discussed.

The aim of this study was to evaluate the factors affecting days open (DO) as the main reproductive performance and longevity index in Holstein dairy cows in Iran. The demographic, production and reproduction data of six large dairy farms were used. The data were analyzed using Standard Least Squares models. Survival analysis using Kaplan-Meier method was used to determine the impact of DO on longevity. The results showed that DO and dystocia were increased during the recent years (P<0.01). Days open was increased due to the higher milk yield in recent years (P<0.01). Non-eutocia calving also increased the DO (P<0.01). Parity impacted DO and cows in their 6th or more lactations had the highest DO (P<0.01). Male calves increased DO (P<0.05). Sire origin had significant impact on DO and Iranian sires had the lowest DO compare to their counterparts (P<0.01). Season of calving had significant influence on DO and cows calved in winter had higher DO compare with their counterparts calved during summer (P<0.01). Increase in DO during the first calving had a negative impact on cow longevity and cows with more than 160 days of DO were culled sooner (P<0.05). In conclusion, the results of the present study demonstrate that DO as the main reproductive performance index is impacted by genetic and environmental factors.