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A simple system to fit the scourge of scours

Losses, treatment costs, and reduced performance can be a $4,000 hit in a 100-head beef herd

Editor’s note: This article from the Beef Cattle Research Council posted last fall offers what could be money-saving advice for producers heading into spring calving. The following is a condensed version. The full article ‘How fresh pens and pastures prevent calf losses’ can be found at www.beefresearch.ca.

Doug Wray believes in keeping newborn calves separated as much as possible from other two-week and older calves to avoid livestock congestion and dramatically reduce the risk of congregated calves developing and spreading scours.

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And for the past several years the plan has worked.

The Irricana rancher has developed this calving-on-pasture system over the past 10 years. In his year-round grazing system, his herd of about 300 bred cows begin calving May 1 on swath grazing and then by May 10 the pregnant cows move to grass and the first batch of cows with calves stay behind.

The first grass pasture is 160 acres in size, divided into eight 20-acre paddocks.

“The herd is managed in one group on pasture for about two weeks before we make the first split,” says Wray. At roughly the first two-week mark, cows with calves (usually about 120 head) “are taken to fresh pasture in one direction, while the bred cows head to new grass in another direction.”

Wray essentially runs two herds at calving season. One group of pregnant cows, that gets smaller with each passing week, and one group of cow-calf pairs that gets larger over the calving season. The pregnant cows are managed on one quarter divided into paddocks, while the cow-calf pairs are managed on another quarter about three-quarters of a mile away. That quarter is also divided into paddocks.

Separating pregnant cows from cow-calf pairs is determined by how fast grass is growing and how many cows have calved.

“On average once we get into mid- and later May we are probably making a split every three or four days to a week,” says Wray. “It is very much a read and react approach.”

Once he has somewhere between 50 and 75 cow-calf pairs in a paddock on the pregnant herd side of the rotation, he trails those cow-calf pairs over to the pair’s quarter section where they join earlier cow-calf pairs.

“The overall principle is to keep both groups of cattle moving to fresh ground,” says Wray. “Quite often we have an environment where we have plenty of fresh growing grass and the sun is shining, and it is very favourable conditions for calving. If we run into a couple of days where it is cold and wet, we won’t move a group of new cow-calf pairs from the pregnant herd side of the rotation over to the pairs rotation. We’ll wait.”

The rotation is good for calf health and also fits with Wray’s pasture management objectives — as grass is rapidly growing he likes to move cattle through quickly to take the first clip off before they return later in the season.

The herd’s breeding season usually runs about 54 days, so the length of calving season is typically one week on either side of that period. By the end of calving season, the herd will be regrouped in a main herd of cow-calf pairs to continue through a rotational grazing system for the summer.

“Our primary objective is to keep newborn calves from being all bunched together and to make sure we’re always calving on fresh ground,” says Wray.

The system has produced excellent results.

“Scours and some of the other newborn calf issues, such as respiratory disease, just aren’t a concern.”

The strategy for healthy calves is to keep newborns separated from older calves and always keep the calving herd moving to new ground to avoid a buildup of disease bacteria.

“The system seems to work well for us because we are calving later, calving on pasture and we are also moving cattle to make sure they have fresh grass,” says Wray.

Sandhills system

The 2014 Western Canada Cow-Calf Survey reported that scours and pneumonia accounted for about 30 per cent of calf deaths. The 2017 survey attributed about 25 per cent of calf deaths to scours. Other research has found performance of calves treated for scours is compromised, resulting in weaning weights anywhere from 15 to 30 pounds lighter.

The overall cost of calf death loss, treatment costs, and reduced performance in a 100-head beef herd with a 20 per cent incidence of scours has been calculated at about $4,000 in a year.

Wray’s system aligns with the Sandhills Calving System developed at the University of Nebraska about 20 years ago. Many Canadian veterinarians and other animal health specialists are encouraging more producers to consider the system, or some variation, to reduce the risk of calf losses due to disease.

Newborn calves commingled with older calves — particularly if concentrated in a relatively small area and if weather conditions are cool and wet — is the ideal scenario for the development of a scours outbreak.

The cycle of scours at calving often originates with mature beef cows as they carry the scours pathogen. Newborn calves often pick up the pathogen and may not become sick, but their guts serve as pathogen multipliers. These calves shed an increasing load of pathogen onto the calving ground, then newborn calves come along and pick up the heavy load of the bacteria. The dose load of pathogens overwhelms the calf’s ability to resist disease.

If a beef herd calves on the same area year after year, the soil can also be contaminated with scour-causing pathogens.

“Among the first considerations — producers need to have enough land available to handle each group of cows and calves over the calving season,” says Dr. Elizabeth Homerosky of Veterinary Agri-Health Services in Airdrie. “The herd should be split about every two weeks with the cows that haven’t calved moved to a fresh pasture. If a producer has a 60-day breeding season, for example, they would need to have planned for five pastures with adequate holding capacity.”

Proper fencing to provide separation of the calved and to-calve herds is important. Homerosky says a single-strand electric wire to divide pastures usually isn’t sufficient as calves can cross under the wire and mix.

Depending on calving season dates, water may need to be available quite early in the spring in each of the pastures.

Newborn calves are most vulnerable to some of the scour-causing pathogens within the first weeks of life, but their immunity grows as each day passes, provided they received adequate and good-quality colostrum at birth, says Homerosky. Once calves reach about four weeks of age their immunity system has developed sufficiently to fight most scour-causing pathogens.

Variations

While the original Sandhills Calving System involves a pasture sequence that leaves cow-calf pairs behind as the yet-to-calve cattle are moved to fresh ground, there are variations. Homerosky has worked to develop a modified Sandhills Calving System with producers who prefer to keep the calving herd close in to corrals and calving facilities and move the cow-calf pairs to new ground. These may be smaller beef operations, purebred producers, or farms with a smaller land base.

“I often refer to it as the Foothills Calving System,” says Homerosky.

This variation is just the reverse described in the Sandhills system and Homerosky recommends cow-calf pairs be moved away from the main pregnant cow herd within 24 hours of calves being born.

For example, if 10 calves are born today, as soon as they have nursed and are ambulatory, move that group to the new paddock or first nursery pasture within 24 hours. If 10 calves are born tomorrow, do the same thing — move those pairs into the paddock or nursery pasture to join up with the first day’s calves.

Keep moving cow-and-newborn-calf pairs into that first nursery pasture for 10 days to two weeks (or before, if the pasture reaches capacity), then add another nursery pasture as needed.

“Newborn calves do not shed any scours pathogens in their manure within the first 24 hours of life, so that’s why it is important to move those calves within 24 hours,” says Homerosky.

By moving the pairs, it limits their exposure to any pathogens that may be present around the main cow herd and they are also not adding to the pathogen load in the calving area.

If by some chance a case of scours does develop, the Foothills system allows a producer to contain or manage the outbreak to within a small group of animals, rather than the whole herd.

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