The Milk Producer - April 2011 - (Page 40)

REARINGREPLACEMENTS By Brian Nelson, Ken Leslie and Vivianne Bielmann Early boost G Research gives new life to mostly abandoned practice of injecting newborn calves with selenium oing back to injecting dairy calves at birth with selenium and vitamin E as a routine, inexpensive practice could help get your young replacement animals off to a healthier start. Research shows calves receiving supplemental injections are less likely to develop viral infections and diarrhea. In the 1980s and 1990s, newborn calves were commonly supplemented with selenium and vitamin E by injections. Beef cow-calf operators still widely use this practice. Today, selenium supplementation to dairy calves is no longer common. Producers generally assume calves get adequate selenium from their dams before birth, as well as through colostrum and milk consumption. Most close-up dry cow rations contain additional selenium and vitamin E. Strategies to increase selenium levels in calves include: • increasing the amount fed to dry cows to boost transfer across the placenta; • administering systemic injections; • increasing selenium quantity in colostrum or milk. Most research over the past 30 years on the importance of selenium in dairy cattle nutrition and health has been on mature cows, related to mastitis control and reproduction. Little effort has looked at the role of selenium in young calves. However, the University of Guelph has conducted research projects recently to investigate selenium status in newborn calves and methods to improve it. This research shows selenium levels vary widely in Ontario calves and among farms. Calf selenium status is inadequate 40 | April 2011 | MilkPRODUCER Treated calves were found less vulnerable to infections and scours. compared with the desired laboratory reference levels for cows. A 2010 report described selenium status of 1,500 newborn dairy heifer calves from 14 southern Ontario dairy farms. It classified about one-third of the calves sampled as selenium deficient. The graph on page 42 shows the calf selenium levels against the accepted reference levels. The average selenium level was barely higher than the lower reference limit of 0.20 micrograms per millilitre. A related project found supplementing maternal colostrum, or colostrum replacer, with selenium did not increase passive transfer of immunity. However, supplementation did increase calves’ whole-blood selenium levels, measured 24 hours after first feeding. Yet, the selenium level in raw colostrum, without extra supplementation, was not strongly associated with whole-blood selenium levels in the calf, measured at 24 hours after colostrum feeding. This study also found the dam’s selenium status should be used only as a rough estimate to predict calf selenium status. Dam and calf selenium levels varied widely. A large field study done during the summer of 2009 determined the ef-

Table of Contents for the Digital Edition of The Milk Producer - April 2011

The Milk Producer - April 2011
Contents
Editor's Notes
DFO Chair's Message
Dairy Update
Industry Roundup
DFC Promotion
Cover Story
Producer Profile
Research
Applied Science
Ruminations
Calf Rearing
Markets
New 'N' Noted
Back Forty

The Milk Producer - April 2011