AIRDRIE, Alta. – A live calf at sale time is the most important detail to a cattle producer.
“If you don’t have a calf, you don’t have any income,” says Alberta Agriculture beef specialist Pat Ramsey.
He said herd reproduction is five times more important than growth rate and 10 times more important than carcass quality.
In an average year, 85 percent of Alberta’s cows produce a weaned calf. The rest are stillborn or die from disease or accidents.
Ramsey said good cow nutrition is vital to ensuring a live calf.
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“Nutrition affects beef cow breeding success more than any other component,” he told a cow feeding seminar in Airdrie, Alta.
A replacement heifer should weigh 85 percent of its mature weight at calving time. If heifers do not get off to a good start early, they are destined to be poor lifetime producers.
Studies show that poorly fed heifers have fertility problems. Only half get pregnant and many fail to come into heat by 14 or15 months of age.
Estrus is affected by weight, growth and genetics. British females tend to mature sooner.
One study showed well-fed heifers have a larger pelvic opening for easier calving.
“About 30 percent of calf death loss is due to calving difficulties,” Ramsey said.
Good nutrition starts in the heifers’ first winter as weaned calves. It is a good idea to feed replacement heifers and thin cows separately from mature animals that push the less aggressive ones away from the best feed.
Feed quality should be analyzed, although Ramsey said only about one third of cattle producers conduct forage tests.
Feed quality and quantity vary following a drought. Producers need to be creative to ensure their heifers and cows are properly fed so healthy calves are born next spring.
Nitrates are a problem this year, with some cases of nitrate poisoning reported this fall. High nitrogen content occurs in plants stressed by frost, cold, cloudy weather or drought. Animals can show poisoning symptoms within a few hours if they go to a high-nitrate feed from a low-nitrate feed.
“It’s that sudden change in the ration that overwhelms the microbes in the rumen and they can’t convert the nitrates to ammonia and get rid of it in the urine,” Ramsey said.
He suggests slowly introducing feed with higher levels of nitrates so the body has time to adjust.
Greenfeed may have more nitrates because of the amount of fertilizer used. Oat greenfeed seems to be the worst.
Less than .5 percent nitrate content is acceptable. Greater than one percent may cause abortions or death.
He said people are adding more straw to their rations this year, but too much straw can cause impaction problems. Protein supplements are also necessary every year.
“I get a little bit concerned when I see cows out on stubble grazing and they’re not provided with some supplemental protein or calcium,” he said.
“If you don’t keep an eye on them they can lose body condition quick.”
Protein feeds the microbes in the rumen, maintains body functions and stimulates hormone and milk production.
Protein deficiency can lead to depression, reduced feed intake, weight loss, poor feed conversion and delayed heat cycle. It can be supplemented with early-cut forages, legumes, soybean and canola meal, pea and lentil screenings, ammoniated feed and commercial supplements.
Calcium and phosphorus are also necessary. Calcium deficiency can lead to slow growth, rickets in calves, weak bones, weak or stillborn calves and milk fever.
A phosphorus deficiency may cause urinary problems, poor growth, weak bones and infertility. Forage loses phosphorus over the summer, so salt blocks go out to pastures late in the season.
Grain tends to be high in phosphorus and low in calcium, while the reverse is true for hay.
For producers who feed a high grain and straw diet, Ramsey recommends adding ground limestone to fill additional calcium needs.
Most producers supplement their cattle for trace minerals such as copper, zinc, manganese, iodine, cobalt and selenium.
Mineral intake depends on the cow, but can also be affected by high sulfate content in water and how much fertilizer is spread on a field. Energy requirements are often not met as cows go into winter. It is the fuel required for weight gain, body movement, heat and reproduction. It comes from fibre, carbohydrates and fat portions in the diet.
Pregnancy imposes a 75 percent greater energy demand on growing females that need to continue developing themselves, as well as support a gestating calf. Poor energy supplies cause poor growth, less milk, increased calving difficulty and a lower immunity.
Extra energy can come from legumes rather than grass. It is a good idea to restrict the amount of straw or chaff females receive. Extra calories are needed for warmth and body maintenance during the winter. Add six mega calories of digestible energy for every 10 degrees below -20 C.
