Effect of intensive fattening of bulls fed a high-grain diet on selected health indicators

Abstract

The aim of the study was to investigate the effect of intensive fattening of bulls with a high-grain diet on selected health parameters. Metabolic indicators under study were compared with those in bulls receiving a traditional diet based on maize silage. The trial included 18 Czech pied bulls that were fed a diet containing from 75.0% to 83.6% concentrate on dry matter basis. As a control, 18 Czech pied bulls were used, given total mixed ration based on maize silage. The experiment was started after weaning when the treated group averaged 114 days of age and the control group 115 days of age. Bulls were slaughtered at an average age of 473 days in the treated group and 474 days in the control group. The experiment lasted 359 days. In the fattening period, blood and rumen fluid samples were withdrawn to evaluate rumen fermentation, acid-base balance and selected biochemical indicators. After the slaughter, samples of tuber coxae cancellous tissue were collected for the bone metabolism assessment. Among indicators under study, the rumen fermentation ones were the most affected by feeding the high-grain diet. Bulls fed the high-grain diet showed (P ≤ 0.05) lower rumen fluid pH and a higher total titration activity, a higher (P ≤ 0.01) total level of VFA and propionate proportion, and a lower (P ≤ 0.01) acetate proportion than the control bulls. Counts of infusoria were also lower (P ≤ 0.01). Acid-base balance was not significantly influenced by feeding the high-grain diet. The high-grain diet fed bulls showed increased serum levels of AST and phosphorus, but the differences from the control group were non-significant in most cases. In 1 g bone ash of the samples of tuber coxae cancellous tissue in the treated group calcium content was significantly (P ≤ 0.05) lower than in the control group; no significant differences were observed between other indicators under investigation.