Ivan Rush: Lice control and heifer development
It has been a wonderful winter in much of the High Plains area so far, allowing producers the option to continue winter grazing. This saves harvested feed, particularly large quantities of hay, which has increased in value considerably.
During this time of year, lice begin to make an appearance – if not previously treated during the fall season. Heavy lice infestation can forfeit production. I expect lice numbers to increase above normal levels due to the mild winter.
Many excellent products are available to help curtail the lice population. Most producers use pour-ons, others find spraying easier, while some chose back rubbers treated with liceacides.
The discussion about biting versus sucking lice, and control of lice eggs, are important concerns. One good pour-on product with a recommended and cleared liceacide can pay big dividends. I recommend rotating insecticides to keep lice resistance to a minimum.
Did you know controlling lice can also help in fence and corral repair? While recently visiting a producer’s place, cattle were rubbing considerably on the wire fence. I mentioned that lice may be the problem, which drew the response, “Yes, we need to get a hot wire around the corral to stop that.”
Data suggests that heavy lice infestation can cost 15-20 pounds of gain on calves being wintered; I’m sure in cases that may be greater in cows. It’s important to control lice on pregnant females to keep the pest from moving to newborn calves.
For those producers who want to remain “natural” and not use insecticides, I ask you this: Is it more comfortable for cattle to have lice biting and chewing on their skin versus those that have lice controlled?
Recently I read a few research reports in the University of Nebraska 2012 Beef Cattle Report that are noteworthy to cow-calf producers.
Rick Funston and fellow researchers at the West Central Research and Extension Center continue to pursue excellent research in the reproduction and management area for cattle producers in the Inter-mountain Range region.
Funston examined 11 years of data on heifer calves born early in the calving season (first one-third, or 21 days). He compared them with the calves born in the second, and third 21 days of the calving season. Not surprisingly, the earlier calves were heavier at weaning because they were older. Study weights were 483, 470 and 434 pounds for the early to late calves, approximately a 50 pound difference from oldest to youngest.
Pre-weaning and post-weaning gain was not greatly different in the study, but pubertal breeding, pregnancy testing and calving weights were heavier for the earlier calves. Of note, calves born form the earlier-calved heifers were significantly lighter at birth than for those from the later-born heifers. Later-born heifers seem to produce heavier calves at birth. Dystocia scores and calving assistance were not significantly, different but tended to favor the larger, earlier-born heifers.
The bottom line of this data indicates that the more calves born early in the calving season will obviously result in heavier calves at weaning. But what we may think of is that the earlier-born heifer calves will maintain that weight advantage the following year, producing more pregnant heifers after the second breeding season.
Another study by Funston and his team looked at different sources of protein for first-calf heifers when supplemented in late gestation.
The UNL West Central research group has conducted considerable research in supplementing mature beef cows grazing Sandhills range and has found a positive effect on progeny performance, carcass quality and health. Reasons for this are not totally understood, but the research has been replicated several times in mature cows. Data has been limited in young, two-year-old heifers pregnant with their first calf.
Researchers fed a group of heifers average-quality meadow hay and were either offered no supplement (the control group) or two treatments with two sources of protein: dried distillers grains (DDG); and dried corn gluten feed (DCGF) at a rate of 1.8 pounds per day.
As expected, two-year-old heifers supplemented with either DDG or DCGF had greater weight gain, dry matter intake and feed efficiency. But what about the effect on their calves in utero? Just as in the mature cow research, calves from supplemented heifers were heavier at weaning and initial feedlot weight. But unlike in the mature cow research, calves from the protein-supplemented dams had similar feedlot performance, carcass characteristics and carcass weight as those from dams with no supplement.
It is not clear why there are performance differences between supplementing mature cows and younger females. We know the heifer is still growing and needs added protein for her own body growth. With all the fetal programming work, discussions continue to be waged as to when fetal programming is triggered: Is it just when the cows’ protein is met, versus cows that are deficient? Or is it when excess protein is in the diet?
The bottom line is that protein supplementation, and in many cases energy supplementation, is important in young, growing two-year-old heifers to maintain adequate body condition, which will result in higher reproduction. Any benefit that is gained in fetal programming is basically a bonus, although it appears to be less in heifers than mature cows.
As a few producers start calving heifers soon, I hope the weather cooperates and that things go well, as you look towards a prosperous New Year.