For many beef farmers, keeping cows and heifers fit and not fat is essential to having a smooth run at calving time.
While thin cows can pose a challenge at calving time, fat cows come with their own set of problems.
If you do nothing to remedy the overweight cow’s condition before they reach calving, and they maintain their level of weight gain in late pregnancy, it can lead to fat buildup near the pelvic canal.
In younger cows and heifers especially, this can cause problems while calving.
Because the pelvis is narrow, when the calf is pushed through the fat gets pushed along under the thin-tissue lining of the birth canal.
This fat can then be concentrated to the point where it causes a tear.
These lacerations in the cow or heifer’s birth canal leaves her exposed to infection – the last thing a cow needs when she has a new calf.
Even though feeding in the final month has some impact on the calf's birth weight, simply rationing the overweight cow a few weeks before calving for a smaller calf will not fix the situation
This is because the size of the calf is mostly determined by the calf's genetics, which were decided 8 months previous, when the cow or heifer was mated.
When cows are in good condition at calving they can compensate for being able to eat less by burning off some of the extra body condition they are carrying and using it as a source of energy.
It is a common but dangerous practice to restrict feed to thin cows in the final month before calving as cows may rapidly lose body condition but it will have little impact on calf size.
Prevention is key, but if it becomes too late, you need to be vigilant of these cattle at calving time. Timely intervention is the vital factor in getting a healthy cow and calf.