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Virginia Cooperative Extension -
 Knowledge for the CommonWealth

Beef Management Tips

Livestock Update, May 1998

A.L. Eller Jr., Extension Animal Scientist Emeritus, Virginia Tech

As I write this column in mid-April, grass is green and cattle are going to summer pasture. Spring has just been the reverse of last year. If you will recall, last year's spring was very dry and late coming. It looks like we have an excellent early pasture season this year and excellent prospects for good first cutting hay crop. Here are some thoughts:

  1. Start Fly Control Programs in May: Horn and face flies are major fly problems for beef cattle in Virginia and elsewhere. Control of these parasites in general should begin in May. Usually there is no significant fly buildup until May or later though it varies some within the boundaries of Virginia. Many producers continue to use fly tags with moderate to good success. Many of these fly tags go into the ears of cows or grazing yearlings in April which is actually a month too early in most cases. Keep in mind there are two basic types of chemicals contained in fly tags which are synthetic pyrethroids and organo phosphates. Various fly tags may contain one or the other and some contain a mixture of both classes of chemicals. The fly tags containing third generation pyrethroids have been among the most effective during the last three or four years. Flies have built up resistance and continue to do so to various chemicals so we have usually recommended that fly tags carrying a different chemical be used each year in a rotation fashion. Old tags should be cut out of cattles' ears at the end of the fly season to cut down on the opportunity for flies to become resistant. For most types of fly tags, the general recommendation for cows is to put a fly tag in each ear though one or more of the new tags only recommend one tag per animal. Nursing calves generally do not need to be fly tagged. Yearlings may get good control with one tag though for many tags on the market, two are recommended. There are still a number of alternatives to fly control. Dust bags properly placed 18 to 24 inches above the ground in areas where cattle use heavily will work well. Back rubbers utilizing appropriate chemicals and number 2 diesel oil as a carrier can also be effective. There are fly control products on the market in the form of pour-ons such as Permectrin CDS. This product and perhaps others can actually be applied as a pour-on, spray, mist or through back rubbers and kill a wide spectrum of insect pests on lactating and non-lactating dairy and beef cattle. These types of topical pour-ons and sprays will no doubt need to be used several times over the course of the grazing season to get good control.
  2. Minerals Important In Summer: Minerals for beef cattle are important year round. For most grazing cattle whether they be stockers, replacement heifers or cows, the three most important ingredients are salt, calcium and phosphorus, though any mineral mix in our region should contain selenium as well. The calcium to phosphorus ratio in commercial or homemade mineral mixes for grazing cattle should be approximately two parts calcium to one part phosphorus. In breeding herds, phosphorus is extremely important as it relates to reproduction. Most mineral mixes should require something in the neighborhood of 40 to 60 parts per million of selenium. Many programs for cow herds should include a mineral mix with magnesium for the prevention of grass tetany particularly in early spring and late fall. Such mineral mixes should contain at least 12% magnesium. There are a number of excellent commercial minerals on the market though many beef cattle producers will make their own mix, providing they have a mechanism for mixing it well. Homemade mixes may be made as follows:
    1. High Magnesium Mineral Mixes: Trace mineralized salt 22 %, dicalcium phosphate 22 %, selenium 600 10%, magnesium oxide 22 % and dry molasses or ground grain 22 %
    2. Mineral Mixes Without Magnesium: Trace mineralized salt 45%, dicalcium phosphate 45%, selenium 600 10%.

If magnesium oxide is used it should be granulular, not powder. Selenium 600 contains 600 parts per million (.06%) selenium. The above mixtures will contain 60 parts per million of selenium.

Producers often asked about vitamins in mineral mixes. Only when cattle consume mature, bleached, severely rain-damaged or other types of low quality forages, are supplemental vitamins A, D or E necessary.

  1. Manage For A 60 Day Breeding Season: A well managed beef cow/calf herd should in most instances put in practice a 60 day breeding and calving season. For herds that have a much wider breeding and calving season then this, it may be necessary to reduce it gradually over two or three years to get it down to 60 days. Why a 60 day season? Assuming that calves are to be weaned and perhaps marketed at a single date on the calendar, for every 30 days later a cow will calve, it will cost about 60 pounds of weaning weight. If a cow gets bred one heat cycle later then would be most desirable, then cost is 40 pounds in weaning weight. The nice thing about a 60 day breeding season is that when bulls are turned in at the start of the breeding season, every cow should be cycling and is subject to being bred on the first or certainly the second heat cycle. To make a 60 day breeding season work cows need to be in average or better condition. On a condition score scale of 1 to 9, the thinnest cows should be 4, the cows in better condition 7, with most cows being in a condition score of 5 or 6. If cows calve in the right condition enough nutrition must be furnished to keep that cow in average condition until breeding season begins. Another consideration is adequate bull power. In a 60 day season, two-year-old and older bulls should be expected to breed 30 to 35 cows and an ideal conditions up to 40 cows. In poorer conditions such as mountain pastures, probably 25 cows. Yearling bulls can handle 15-20 cows. If conditions are severe 15 and if conditions are good maybe as many of 25 cows. Don't expect too much from a yearling bull. Be sure that yearling bulls and older bulls are not put together in a multi-bull breeding pasture because the dominance of the older bull will dictate that he will do most of the breeding. Herd health is another consideration. Cows should be vaccinated when open prior to the breeding season for IBR, PI3, BVD, five strains of Lepto and Vibriosis. In a cow herd with good management that are currently using a 80 or 90 day breeding season, a 60 day breeding season is very attainable. First calf heifers probably should be cut a little closer and given a 45 day breeding season. Heifers that calve early the first time are much easier to keep on schedule in subsequent years.
  2. What Frame Size Is Right: When I think back several years into the 1960s and 70s, we had lots of cattle that were three and four frame score. These cattle were a bit on the small side to produce progeny that would finish at 1100 to 1300 pounds. Most purebred breeders decided that what their cattle needed was more frame size. We saw breeders go on a frame size single-trait selection binge that produced lots of cattle that were 7, 8 and 9 frame score and we realized we had gone too far. In the last several years we have seen frame sizes come back down. There have been some concerns expressed that "this is fine but don't get them too small again". Looking at cattle coming out of the feedlot, weighing 1100 to 1300 pound, the bulk of these cattle would be frame score 5 and 6 which means as feeder cattle that many of them would be medium frame feeder cattle and some over into the large frame category. In a cow herd where replacements are raised, we control frame size largely by the bulls we use. I truly believe there is room for frame scores in bulls to go from 4 to 8. But for the most part, 5, 6 and 7 frame score bulls are those that will fill the greatest need. In fact, for most cow herds, frame score 5 and 6 bulls are the ones today that are most popular and rightly so. Their progeny will gain rapidly and finish at 1100 to 1300 pounds and will do it efficiently. The 5 to 6 frame score bull has been a popular item for the last several years and is probably just about right for the industry.
  3. Plan To Deworm Spring Calves In Mid-Summer: I realize it is a bit early here in May, but now is the time to plan to deworm spring born calves about early to mid July. Our research and field studies have well proven that this is a paying proposition and any number of excellent deworming materials may be selected to get the job done. Put mid-summer calf deworming on your work schedule calendar and make sure it happens. You will add pounds of calf at weaning and improve profitability.
  4. BIF Convention at Calgary Alberta, Canada: The 1998 Beef Improvement Federation annual Convention will be held June 30 to July 2 at the International Hotel in Calgary Alberta, Canada. For reservations in Calgary contact Carlson Wagonlit Group Department, 705 Fifth Street SW, Calgary Alberta, Canada T2P1V8, 1-800-696-3505 or contact Ron Bolze, Executive Director of BIF at Northwest Research Extension Center, P.O. Box 786, Colby, Kansas 67701, 785-462-6281.



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