By Bonomi, A., Rivista di Scienza dell'Alimentazione, 1999
Description
Relationships between the manganese content of the ration and its effects on zinc deficiency in dairy cows was examined through studies carried out on 3 farms. 90 Italian Friesian cows were fed with rations containing a normal level of zinc (50 p.p.m.) and manganese levels of 30 (controls), 40, 60 and 80 p.p.m. At manganese levels of 80 p.p.m., cows showed a secondary zinc deficiency with a decrease in plasma zinc content (from 90-70 ‘g/100 ml), an increase in lesions in the soft tissues of the feet (digital and interdigital dermatitis, interdigital hyperplasia, interdigital phleamon) in 47% of cows, reduced reproductive efficiency (2.30 services per conception vs. 1.65 in controls), a decrease in milk yield of 11%, and an increase of 30% in the incidence of common diseases (mastitis, ovarian cysts, metritis and silent oestrus). Feeding zinc carbonate (2 g/head per day) to the cows with foot disease contributed to a more rapid healing of tissues than in controls (20 vs. 50 days; P<0.05)
Relationships between the manganese content of the ration and its effects on zinc deficiency in dairy cows was examined through studies carried out on 3 farms. 90 Italian Friesian cows were fed with rations containing a normal level of zinc (50 p.p.m.) and manganese levels of 30 (controls), 40, 60 and 80 p.p.m. At manganese levels of 80 p.p.m., cows showed a secondary zinc deficiency with a decrease in plasma zinc content (from 90-70 ‘g/100 ml), an increase in lesions in the soft tissues of the feet (digital and interdigital dermatitis, interdigital hyperplasia, interdigital phleamon) in 47% of cows, reduced reproductive efficiency (2.30 services per conception vs. 1.65 in controls), a decrease in milk yield of 11%, and an increase of 30% in the incidence of common diseases (mastitis, ovarian cysts, metritis and silent oestrus). Feeding zinc carbonate (2 g/head per day) to the cows with foot disease contributed to a more rapid healing of tissues than in controls (20 vs. 50 days; P<0.05)
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