The effect of levels of concentrate in feedlot diets on the health status of beef calves

In this two year study we investigated the effect that the level of concentrate in feedlot diet had on the occurrence of health problems in bull calves belonging to two multibreed groups.

In each of the two years, the 168 day feedlot period was divided into two equal periods of 77 days with an intervening 14 day adjustment period. During the first period, the animals in half of the pens within each breed-group received a high concentrate (85% grain) diet (H) while the rest of the pens received a diet (L) of hay ad libitum and half as much concentrate as the bulls on high concentrate. The L diet contained an average of 48% grain. In the second period, diets of bulls in half of the pens within each breed-group were switched from L to H and vice versa. During the feedlot period, the incidence of sickness among bulls was recorded. Disease incidence was higher in the second year compared to the first. In the second year, 49 out of 56 (87.5%) calves on the high concentrate diet required treatment for respiratory infections compared to only four (7.14%) in bulls on the low concentrate diet. The results suggest that a high concentrate diet for animals in feedlots may be more stressful to calves coming directly to the feedlot following weaning compared to a low concentrate diet, thereby acting as an additional predisposing factor to respiratory infections.

     

Evolving perceptions of bluetongue: A challenge for government and industry

From the first discovery of bluetongue virus activity in Canada in the Okanagan Valley of British Columbia in 1976 to the present, more than 175,000 sera from cattle in Canada have been tested for the presence of bluetongue antibody during the course of disease investigations and during regional or national surveys. Serological reactors have been detected only in cattle resident in the Okanagan Valley or in those originating in the United States.

Despite the regional nature of the distribution of antibody to bluetongue, international trade sanctions were applied on a nationwide basis. The strategy of the federal government for limiting the international, as well as the domestic, impact of bluetongue has evolved over the past 15 years as the epizootiology of bluetongue has become better understood. This new information is also ameliorating somewhat international attitudes toward nations which experience infections.