Careful antemortem examination and interpretation of findings, assisted by good clinical records, do much to throw light on the nature of vertical fissure in cattle. During an eight month period of investigation, 13 (3.2%) lame cows with vertical fissure out of 52 Holstein cows with different claw fissures were selected for clinical and gross pathological purposes in a commercial dairy farm wit...

British breeds of cattle are not so effective as Zebu in extracting nutrients from low-quality roughages, and these breeds differ in their nutrient metabolism and animal physiology. Breeds of cattle may differ in their requirements for Mg. Brahman cows are less susceptible to death from disease and metabolic disorders than are British breeds of cattle, whereas cows with 50% or greater dairy bre...

In pasture-based seasonal calving systems, failure to become pregnant during the breeding season results in important economic losses as maximum profit is attained by minimising costs and increasing the proportion of grass in the diet of the lactating dairy cow. In the United States, dairy producers primarily strive to maximise production potential but are becoming increasingly aware of the eco...

Forty-eight Holstein and Guernsey cows were assigned according to age and breed to one of seven groups based on days following parturition. Cows in Groups II to VII received an intramuscular injection of 100 ~tg gonadotropin releasing hormone (GnRH) on either 1 or 2, 3 or 4, 5 or 6, 7 or 8, 12 or 13, or 18 or 19 days postpartum, respectively (six cows per group). An injection of the carrier veh...

Bovine genital campylobacteriosis is one of the most economically important diseases of dairy cattleresulting in lowered fertility, embryo mortality and abortion, repeated returns to service, reduced pregnancyrates and extended calving intervals. While the occurrence of repeat breeding syndrome and abortions arereported from many Iranian dairy cattle farms, little information is available regar...

Mastitis is one of the most prevalent diseases in cattle and remains among the most costly diseases to the dairy industry. Various surveys have indicated a greater prevalence of and risk for mastitis in Holstein cows than in Jersey cows. The innate immune system comprises the immediate host defense mechanisms that respond to infection, and differences in the magnitude and rapidity of this respo...

Two experiments were conducted to evaluate seasonal variation in oocyte competence in Holstein cows and to test whether oocyte quality in summer is affected by the magnitude of heat stress. In the first experiment, ovaries of Holstein cows were collected from a slaughterhouse and used to harvest oocytes over 1 yr (n = 18 replicates). After in vitro maturation, fertilization, and culture, propor...

Lipid peroxidation can be described as a process under which free radicals attack carbon double bonds of omega-3 and omega-6 fatty acids. Whereas the end products of this process are reactive aldehydes, such as malondialdehyde (MDA). Lipid peroxidation leads to adverse changes in the nutritional value of milk; therefore, higher degree of antioxidant protection (DAP) ensures higher stability of ...

The effects of flax meal (FM) on the activity of antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT)) in the blood, mammary tissue and ruminal fluid, and oxidative stress indicators (thiobarbituric acid-reactive substances(TBARS) and 1,1-diphenyl-2-picrylhydrazyl-scavenging activity) in the milk, plasma and ruminal fluid of dairy cows were determined...