Ohio Beef Newsletter

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April 4, 2007

Managing the Environment for Controlling Scours - William P. Shulaw DVM, Extension Veterinarian

Calf scours is one of the most common animal health concerns of Ohio producers at this time of year. Various studies have suggested that scours are the cause of 15-20% of all calf deaths prior to weaning. Scours are caused by bacteria (E. coli, Salmonella spp., Clostridium perfringens), viruses (coronavirus, rotavirus) and protozoa (Cryptosporidium parvum, or "crypto", and in older calves - coccidia of the Eimeria spp.). Most of these infections are actually carried and spread in manure and on body surfaces by healthy-appearing adult cows. Disease results when management and environmental conditions favor their transmission and the calf's resistance is reduced. In fact many of these organisms are present on many, if not MOST, farms (dairy and beef) but may not cause enough loss to be recognized until conditions are favorable for an outbreak of scours. As an example, in an Ohio State study of Cryptosporidium on dairy farms, all four farms studied were infected, and over 85% of all calves on each farm became infected during the first 3 weeks of life. Calf scours were not identified as a significant problem except on one farm on which Salmonella in scouring calves was also identified. Other studies have revealed similar data. Reports of studies by the National Animal Health Monitoring System suggest that at least 40% of cow/calf operations have Cryptosporidia infections. Cold and wet weather, mud, overcrowding, poor sanitation, poor nutrition of the cows, and dystocia (or calving difficulty) are all factors that favor the development of scours.

When a scours outbreak occurs, producers often focus a great deal of labor and money on treatment of calves with fluids and antibiotics, but the environment may not be recognized as an important part of the problem. Once the first case of scours develops, even a clean environment often becomes extremely contaminated very quickly. Calves with E. coli scours may be shedding billions of bacteria in a single stool. A similar situation occurs with the viruses where it has been estimated that within three days of infection, a calf may be shedding 500,000,000,000 virus particles in a teaspoon of stool material. In our work with crypto, we measured the shedding of Cryptosporidium parvum as high as 17 million oocysts per cc of stool in some calves. With this organism, infection may occur with ingestion of as few as 10 oocysts. Cows carry scour-causing organisms on their udder, hair coat, and feet and legs and spread them around the environment ensuring that other susceptible calves are exposed unless something is done to reduce the potential for calf exposure.

Over the years, several strategies to limit environmental contamination and calf exposure to scours pathogens have been described. Because calves born to heifers are often more at risk, it is a good idea to feed and calve heifers in separate areas from the cowherd. Various strategies have suggested moving pregnant cows from the wintering area to a clean calving area one to two weeks before calving begins. If the herd is large and approximate breeding dates are known, dividing it into smaller, more manageable groups may be helpful. In one of these systems, producers are advised to move cow-calf pairs to different nursery areas within a day of calving and manage them as small groups. If scours breaks out in one of these groups, no new calves are added to the group and care is taken not to spread the contamination from that group by equipment or people. (People can be efficient spreaders of disease-causing organisms.) The idea is to try to limit the infection and pathogen load, as well as the labor of treatment, to one area. When the calves in these groups are three to four weeks old, they may then be moved to spring/summer grazing areas.

Over the last four to five years, Dr. David Smith and his colleagues at the University of Nebraska-Lincoln have developed and demonstrated the Sandhills Calving System (sometimes called the "Sandhills Shuffle") as a tool for preventing or reducing calf scours. The objective of this system is to prevent "effective contact" of calves with calf scours pathogens(germs). An effective contact is defined as an exposure of the calf to pathogens in a dose, or for a duration of time, sufficient to cause disease. In the Sandhills system, effective contacts are minimized by 1) segregating calves by age to prevent transmission of pathogens from older to younger calves; and 2) scheduled movement of pregnant cows to clean calving pastures. The overall idea is to re-create the more ideal conditions that are usually present at the start of calving season at each subsequent week of the calving season.

The system uses several clean pastures for calving rather than a high animal density lot or pasture. In practice, the cows are turned into the first pasture as soon as the first cow calves, and calving continues for two weeks. At the end of two weeks, the cows that have not calved are moved to a second pasture and the existing cow/calf pairs stay in the first pasture. After a week of calving in the second pasture, pregnant cows are again moved to a third pasture and the cows that calved remain in pasture two. Each subsequent week, cows that have not yet calved are moved to a new pasture thus distributing cows with calves within one week-of-age of each other in separate groups. Cattle from different pastures may be commingled after the youngest calf in a group is four weeks old. Generally, calves of this age are at low risk for scours.

The success of this system relies on two key principles. Age segregation of calves helps prevent the transmission of pathogens from older calves to younger calves and assists in management of scours outbreaks within groups if this does happen. The routine movement of pregnant cows to fresh calving pastures helps prevent the buildup of scours-causing germs in the calving environment that often leads to exposure of the youngest calves to overwhelming doses in more conventional systems where cow/calf pairs are not segregated.

Moving pregnant cows can be easier and less disruptive than moving cow/calf pairs, and each week the number of cows in the group that has to be watched for calving is reduced. If pregnancy examination information is available, cows that are expected to calve later in the calving season can be maintained as a separate group and added to the system as appropriate.

This system should be planned well ahead of the calving season to maximize its potential. It may be somewhat difficult for some farms to adopt it because of pasture, water, or shelter limitations. In addition, the planning has to take into account potential weather conditions likely to occur during the calving season and the potential for damage to pastures if it turns wet and muddy. However, with some "tweaking" of the system, many Ohio herd owners could develop a farm-specific plan that utilizes the basic principles of the Sandhills system. Combined with a sound nutrition program; an effective reproductive management program, including breeding soundness exams in bulls; a vaccination program; and a biosecurity program, the negative impact of calf scours can be minimized.


Forage Focus: Grass Needs N - But Not Now - Jeff McCutcheon, Extension Educator, Knox County

This week in Ohio it became obvious, the spring flush is starting. Ok it may slow down this weekend due to the cold front but with the recent warm weather and the abundance of moisture, grasses have broken dormancy and are (were) growing rapidly. On recent farm visits I observed pastures with 4-6 inches of growth or around1800 to 2400 lbs. of dry matter per acre. Orchardgrass had 4-5 leaves emerged and fescue 3-4 leaves emerged. Now is the time to manage grazing. Applying nitrogen will only make the management harder.

It is true that nitrogen is essential for grass growth and nitrogen fertilizer should be considered for a grass dominant pasture. Grass pastures will respond quickly to nitrogen. When you use it make sure you can utilize the forage produced.

Since our cool season pastures produce over 60% of their growth in the spring and most of us can not effectively utilize that growth, an early spring application does not help.

The only advantage to an early spring application of nitrogen on our pastures is about a two week jump start.

Save the nitrogen for your pastures till June when the spring flush is over and we are heading into the summer slump. Or better yet incorporate legumes into your pastures to supply the nitrogen for you.


Cattle Demand Strengthens - Brian Roe, Associate Professor AED Economics, Ohio State University, April 3, 2007

Despite the wintry weather experienced out west during the early parts of 2007, February beef production was up 7% compared to the previous year with a 9% increase in the number of cattle slaughtered being tempered by a 2% decline in dressed weights. Despite the surge in production, average prices were only about 40 cents lower than February 2006, suggesting that demand for live cattle strengthened during the month of February. Had demand been equal to that of 2006, average cattle prices would have sold in the upper $70's rather than the upper $80's as they did during February. In other words, stronger demand meant about $9 per hundred more for fat cattle in February 2007 than February 2006.

Will this demand strength carry forward through April and June? So far, it looks that way. In April of 2006, prices averaged only about $81 on very heavy sales volume. Compare that to recent April futures contracts, which are trading around $99. If cattle demand this April were to match last April's demand, it would take a 10% decline in dressed beef during April to explain that $99 futures price. Since a 10% decline isn't likely in the cards - a 3 or 4 % decline is more likely - it suggests the futures market price includes an $11-12 dollar demand premium over last year. That's $2-3 more than the bump we saw in February, i.e., the futures market is building in even greater demand strength than was observed in February.

The Cattle on Feed report also suggests that the number of cattle coming to market during May and June will be smaller than last year due to fewer placements of lightweight cattle onto feedlots late last fall and due to fewer placements of heavier feeder cattle on feedlots during the snowstorms of January. Recently, June futures contracts were trading at $96.40. If demand were merely as strong as last year's June demand, beef production would have to be about 8% lower than last year to justify such a futures price. A 3% reduction in beef supply might be more likely in June. This suggests that the $96.40 futures price is predicting a June cattle demand that is about $10 stronger than last year's June demand, which is in line with February and April improved cattle demand figures.

In Eastern Corn Belt feeder cattle markets, the 30 cent decline in cash corn prices during March has not immediately spilled over to higher cattle prices - light weight feeder prices were flat during March while heavier weight feeders gained a few dollars. Furthermore, the decline in corn prices has not been enough to allow the price slide between the lightest and heaviest feeders to expand as it has during the past few years. That is, during 2005 and 2006, the per pound price difference between 300 pound and 800 pound feeder cattle has usually increased from the upper-$20's during January and February to the $40's by March and April. This year that price difference between weight groups is still in the $30's, meaning that the decrease in corn price is not large enough to allow buyers to confidently buy lighter weight feeders that will consume so much corn in the months to come.

The decrease in corn price has made dried distillers grains less attractive, however. During late February, the substitution of one ton of dried distillers grains for 26.1 bushels of corn and 420 pounds of soybean meal would provide a savings of about $15-20. By late March the cost advantage of such a switch declined to about $5. The question becomes - will the increase in ethanol production eventually start to drive the price of distillers grains lower on a more permanent basis?


HEIFER DEVELOPMENT: Target Weight Concept - Steve Boyles, OSU Extension Beef Team

The Target Weight Concept is a method to control the amount of gain. We thereby assure the heifers attain enough gain to attain puberty but also avoid getting them too fat. Rates of gain not lower than 1 lb. or greater than 2.O lbs. per day reflect the needs of most of our current cattle population. For example, a heifer weighs 450 lbs. at weaning and has a target puberty weight of 675 lbs. There are 200 days between weaning and breeding. We would actually prefer her to reach puberty weight at least 2 to 3 cycles before breeding (160 days).

(675-450)/160 = 1.4 lbs of gain per day

Rations can be formulated to meet the nutritional requirements for this amount of gain. The rate of gain need not be constant over the entire period, as long as the target weight is reached. Typical gain targets from weaning to breeding are 1.25 to 1.5 lbs per day for British breed type heifers and 1.5 to 1.75 lbs per day for Continental breed types. Some research identifies advantages to developing heifers in stages of reduced energy and gain followed by periods of compensatory growth. A slight reduction in feed expenses has been shown for heifers developed at fairly slow rates of gain early followed by a period of accelerated growth just prior to breeding.

Target weights and gains for developing replacement heifers

Stage of development      Age, months                Target weight, lbs    % of mature        Target gain lbs/day
Weaning period                          8                                  450                                  41                      1.75
Post-weaning to breeding          9                                  500                                  45                      1.25
Breeding to calving                    14                                684                                  62                        .8
Calving to rebreeding                23                                880                                  80                          .4
Second breeding season            27                                927                                  84                          .4
Second calving                          36                              1012                                  92                          .2

The gain can be increased through supplementation during the winter feeding period if previous experience on the farm tells us that heifer gains on pasture just prior to the breeding season are less than adequate. Heifers going to adequate pasture, prior to breeding can be expected to gain from .75 to 1.4 pounds daily. Knowing forage quality means knowing whether protein, energy or both must be supplemented. Computer ration balancing services are available through the county extension offices and probably through the local feed dealer.


Ohio Cattlemen's Association Seedstock Improvement Sales Catalogs Now Online - Bill Doig, MS, Beef Program Specialist, OCA/OSUE

Breeding season is just around the corner. Do you have your herd bulls lined up for this year? The Ohio Cattlemen's Association Seedstock Improvement Bull Sales offer the solutions for all types of bulls you might be searching for. We invite you to the 2007 Seedstock Improvement Sales set for Saturday, April 14 at the Union Stock Yards Company in Hillsboro, Ohio, and on Friday, May 4 at the Muskingum Livestock Auction Company in Zanesville, Ohio.

Sixty eight (68) bulls will be selling at Union Stock Yards and 53 bulls will be selling at Muskingum. The bulls, ranging in age from 1-5 years, are all registered and have expected progeny differences (EPDs). Many of the proven bulls available will have additional performance based information including offspring data. Breeds represented are Angus, Hereford, Maine Anjou, Limousin, Romanola and Simmental. Some of the top genetics in the country are represented in the sales.

For your convenience, the catalogs are now available online at www.ohiocattle.org by clicking under the Beef Improvement Tab and then Seedstock Sales. If you have any additional questions, or would like to request a hard copy of the catalog, please contact Bill Doig at [email protected], or by calling 614-873-6736






 
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