Logistic regression models were used to examine the relationship between milk yield and incidence of certain disorders. Lactations (n = 2197) of 1074 Holstein-Friesian cows from 10 dairies (25 to 146 cows per dairy) in Lower Saxony were studied. The 305-d yield from the previous and current lactations served as the standards for milk yield. Eight disorder complexes were considered: retained placenta, metritis, ovarian cysts, mastitis, claw diseases, milk fever, ketosis, and displaced abomasum. Each disorder complex was modeled separately. In addition to milk yield, the influences of the lactation number, the calving season and the other disorder complexes were examined with the "herd" factor taken into account. A correlation between retained placenta, mastitis, and milk fever to milk yield during the previous lactation was found to be probable and for ketosis and displaced abomasum such a correlation was found to be possible. A connection to the yield in the current lactation was shown for ovarian cysts, claw diseases, and milk fever. No relationship to milk yield existed for metritis. An influence of the lactation number was also demonstrated in various models. Single models allowed a demonstration of the influences of both milk yield and lactation number. Limitations of the model types are discussed.

ABSTRACT:The aim of the study was to monitor the effect of increased iodine supplementation of the clinically healthy kid organism on the selenium status. The study included 7 clinically healthy 14-day-old kids from mothers with high iodine supplementation (group E) and 7 clinically healthy kids from mothers with hypoiodaemia (group C). Kids in group E were administered potassium iodide orally from 14 to 90 days of age. During the experimental period, the group E kids had a total daily iodine intake (from the feeding ration and from the per os potassium iodide administration) of 440-590 µg per head and day in comparison with 140-190 µg per head and day in the group C kids (only from the feeding ration; no potassium iodide administration). In kids of both groups, selenium concentration (Se), glutathione peroxidase activity (GSH-Px), concentration of the thyroid gland hormones (T 3 and T 4 ) and animal weights were monitored. In the group E kids, lower Se concentration (88.1 ± 10.9 µg/l; P < 0.01) and lower activity of GSH-Px (484.0 ± 125.4 µkat/l; P < 0.05) were proved at the end of the experiment (at 105 days of age of the kids) in comparison with the group C kids (131.8 ± 23.2 µg/l and 713.3 ± 153.3 µkat/l, respectively). No significant differences were found out in the T 3 or T 4 concentrations or in the weights of animals of both groups. The results indicate that increased iodine supplementation may have a negative effect on selenium metabolism and/or selenium status in kids.

Abstract

Passive transfer of immunity in dairy calves is routinely monitored in North America. This study analyzes such type of biochemistry monitoring in 591 calves (Holstein, Fleckvieh) from 19 large farms in the Czech Republic. All calves, aged 1-6 days, were blood sampled once. Serum concentrations of total protein, albumin, zinc sulphate turbidity units and γ-glutamyltransferase activity were analysed by photometry methods. The samples were divided according to concentrations of total protein and zinc sulphate turbidity units, and the age of calves. These groups were compared using nonparametric tests. The samples had good mean values (total protein 63.5 g·l -1 , albumin 30.5 g·l -1 , zinc sulphate turbidity 11.5 U, γ-glutamyltransferase 10.7 μkat·l -1 ) but 41% and 54% of calves had low total protein (< 60 g·l -1

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