As the dairy-beef crossbreeding phenomenon continues to evolve, there remain unsolved challenges to maximizing the performance and value of those animals.
We know those calves aren’t the same as fullblood, conventional beef animals. And we know we can’t feed and raise them exactly the same. But can we get closer to matching the performance of their beef cousins, particularly related to challenges like their currently high incidence of liver abscesses?
A recent Iowa State University study sought to bring some clarity to the lifetime nutrition of beef-cross animals, and how it influences their performance and ultimate carcass quality. The study started with 120 day-old, dairy-beef cross steers, and segmented them into 4 feeding groups:
- A high-starch starter ration for 60 days, followed by a high-starch pelleted ration for 60 days.
- A high-starch starter ration for 60 days, followed by a forage-based TMR ration for 60 days.
- A low-starch starter ration for 60 days, followed by the high-starch pelleted ration for 60 days.
- A low-starch starter ration for 60 days, followed by the forage-based TMR ration for 60 days.
All calves were weaned from a common liquid ration at 60 days. Following the 60-day postweaning experimental phase, the entire study group was fed a common grower TMR ration for 140 days, and a common finishing diet for another 200 days.
In the post-weaning receiving phase, the two groups fed the pelleted ration had significantly higher feed intake, average daily gain (ADG), and ending weight. However, that disparity narrowed during the grower phase. By the end of the grower phase (~260 days), there was no significant difference in bodyweight between the four groups.
In the finishing phase, there was also no significant difference in feed intake or ADG between any group. But the low starch/TMR group was unique in that it had a slightly different growth curve. Those calves continued steadily increasing in daily feed intake and growth as the other calves were slowing down.
“Some of this may be due to compensatory gain following the receiving phase, but we speculate some may also be due to a healthier rumen in the later finishing period,” said Iowa State Extension Beef Specialist Denise Schwab, primary investigator of the study.
Harvest data indicated no difference in the quality grade, yield grade, or carcass weights between the four groups, but the low starch/TMR group had slightly heavier carcass weights.
Most telling was the disparity in the incidence of liver abscesses and condemned rumens. In total, the incidence of liver abscesses across all groups was 19%, which is well below current industry incidence for dairy-beef cross steers. The high starch/TMR group had more than 30% incidence of liver abscesses, while the low starch/TMR group had less than 5%.
Rumen condemnations were highest for the high starch/high starch pellet group, at 19%. Comparatively, the low starch/TMR group was the lowest, at just 4%. Overall, the low starch/TMR group had an average of 20% fewer liver abscesses and rumen condemnations compared to the other three groups.
In terms of numeric economic returns, the low starch/TMR group had the highest average carcass value, and the high starch/TMR group had the highest net economic returns.
A summary of the study, which was supported by the Iowa Beef Industry Council and Iowa Beef Checkoff, can be found here.
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