Effect of restricted feeding on the live weight of suckler cows and their calves, quality of colostrum and calf serum IgG concentration

Anna-Kaisa Rytkönen, Laura Hänninen and Merja Manninen


To resist environmental infection pressure, a newborn calf must build up a good passive immunity in its fi rst 24 h of life by absorbing a suffi cient amount of immunoglobulin from colostrum. Considerable economic losses are incurred by the beef industry each year due to high calf mortality and morbidity. To counteract high feeding costs, feeding is restricted during the suckler cows's dry period. However, an overlay aggressive restriction can weaken the quality of the dam’s colostrum and lower calves' vital serum IgG (S-IgG) concentration. Our goal was to determine the effect of pre-partum feed restriction on suckler cow colostrum quality, live weight and condition. Live weight gain of calves and their S-IgG concentrations were also monitored. We studied 32 Hereford-crossed dam-calf pairs. The dams were fed 90 days prior to partum with wilted silage according to feeding recommendations (Y) or 75% of recommended feeding levels (A). A-dams tended to have lower condition score at calving than Y-dams (p<0.10) while feeding had no effect on colostrum IgG concentration. A-calves had approximately 4 g/l less S-IgG than Y-calves (p<0.01). In conclusion, although A-dams had lower condition scores and live weight than Y-dams, colostrum quality remained unaffected. The slightly lower S-IgG concentration of calves of restricted-feed dams may, however, be a risk factor on problem farms.