DICKINSON, N.D. -- The Dickinson Research Extension Center is busy calving heifers. The heifers were bred May 22. The calving season started five days early on Feb. 24, with one calf born dead.
That was followed with one calf on the 25th that was assisted, two calves on the 26th with no assists, three calves on the 27th with no assists, six calves on the 28th with one assist, eight calves on March 1 with one assist, three calves on the 2nd with one assist, three calves on the 3rd with one assist, three calves on the 4th with no assists, nine calves on the 5th with four assists, two calves on the 6th that were both assisted, one calf on the 7th that was assisted, and one heifer on the 8th with no assistance.
The fact that eight heifers calved on their due date is noteworthy. Now that the calves are on the ground and we have worked through the difficulties and extra management and labor, the influence of gestation length provides measureable data.
Of the 21 heifers that calved on or before the actual calving date, the average birth weight was 83.4 pounds and only three of the heifers (14 percent) required assistance. Of the 22 heifers that calved after the due date, the average birth weight was 88.7 pounds and nine of the heifers (41 percent) required assistance.
The average gestation length for those heifers that calved on or before their due date was 281.7 days and the average gestation length for those heifers that calved after their gestational due date was 286.5 days. The difference of 4.8 days in gestation length was 5.3 pounds in birth weight, which is 1.1 pounds per day of fetal growth in these heifers. This is not a good thing and only can be controlled by selecting the right bull.
The bottom line, in an effort to lower calving difficulty, the average birth weight of the calf needs to be sufficiently lowered to account for a lower birth weight and for calves that may not be born on time.
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http://www.ag.ndsu.edu/news/columns/beeftalk/beeftalk-unwanted-calf-average-daily-gain
Contacts:
Kris Ringwall, (701) 483-2348, ext. 103, kris.ringwall@ndsu.edu
Rich Mattern, (701) 231-6136, richard.mattern@ndsu.edu
