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31.
A longitudinal study of the feet of cows from a seasonal dairy herd was conducted over a 12 month period to measure the occurrence of subclinical hoof lesions. Eleven 2-year-old cows, entering the herd for the first time, and eleven mature cows were randomly selected from a herd of 415 cows at the end of winter (July 1989) prior to calving. The incidence of lameness in the herd over the 12 months was 2%. None of the trial cows became lame during the study. Cows were examined monthly. The type, severity and location of any hoof lesions were recorded. Sole haemorrhage, erosion of the heel bulb and minor white line separation were the most commonly observed lesions. These lesions were observed with specific claw distributions in the cow and at specific times of the year and breeding season, with waves of each type of lesion passing through the herd at a particular time. White line separation was observed commonly during spring (up to 37% of digits affected), disappeared almost completely over the dry summer months and reappeared in autumn, increasing to 40%' again over winter. Lesions were more commonly observed in the lateral digits, with fore feet being more commonly affected than hind feet. Erosion of the heel bulbs was common in August (65% of digits affected, more common in mature cows than 2-year-olds), disappeared quickly during spring, and reappeared in all cows during the following winter (88% of digits; no age differences). There were no differences in distribution between digits. Sole haemorrhages were concentrated over the mid-sole and abaxial sole zones. They were more common in the hind feet than the front feet and more common in the outside claws (p < 0.001). Haemorrhages were not observed prior to or soon after calving, appeared in October and reached a peak of 40% in December, then gradually disappeared by the time of drying-off in May. The 2-year-olds were more frequently affected than the mature cows (p <0.001). 相似文献
32.
Hoof growth and wear studies were conducted on ten spring-calving cows over 12 months. The rates of hoof wall growth and wear were lower in autumn and winter than during spring and summer. Both were greater in 2-year-old than in mature cows (p<0.05). Sole wear occurred most rapidly along the abaxial edge of the weight-bearing surface, less quickly in the toe and heel areas, and most slowly in the mid-sole region. Both hoof wall wear and sole wear were greater in lateral digits than in medial digits (p<0.01). Sole concavity, measured using a profile gauge, was greater in 2-year-olds prior to calving than in mature-aged cows (p<0.05) but this difference disappeared soon after calving as concavity was lost in the younger cows. Medial digits almost always had greater concavity than lateral digits. Sole concavity measurements were also made on the hind digits of 24 autumn-calving cows on four occasions at 2-monthly intervals. Prior to calving, concavity was much greater in these cows than in the spring-calving cows. However, concavity was lost rapidly following calving and concavity measurements were soon similar to those found in the spring-calving cows. 相似文献
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One hundred Queensland stockfeeds were examined for their counts of total aerobic bacteria, coliforms, fungi and salmonellas. The total aerobic bacteria, coliform and fungal counts were significantly higher (P < 0.005) for mashes than for crumbles and pellets and salmonellas were isolated from significantly more (P < 0.005) mashes (64%) than pellets and crumbles (8%). Counts of less than 1 salmonella per 100 g were found in 36.4% of the 44 positive feeds. The remainder of the counts ranged from 1.2 per 100 g to greater than 147 salmonellas per 100 g feed. 相似文献
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