Nutrition: fact from fiction

SAN ANTONIO, Texas — Listening to friends at the coffee shop or searching the internet may not be the best way to get sound animal nutrition advice.

In a tag team event, animal nutritionists Dusty Abney and Wesley Moore of the international feed company Provimi busted some common nutrition myths at the recent National Cattlemen’s Beef Association convention in San Antonio, Texas.

Myth: How big are your cows?

Many people estimate their cows weigh about 1,200 pounds. In reality they likely weigh at least 1,400 lb.

“The importance of knowing what the cow weighs is critical in developing your nutrition program,” said Moore.

“Body weight is everything, especially if trying to feed them efficiently and at the least cost,” he said.

An extra 100 lb. of cow body weight requires another 2.2 lb. more total digestible energy and an extra half a pound more of protein for the cow to maintain body weight. If the ration was developed for a 1,200 lb. cow that actually weighs more, the result is underfeeding.

Cow weight varies throughout the year, so an on-farm scale is a good investment.

“Match your cows to your environment and calving to your forage base,” Abney said.

Invest in feed when it is needed. Don’t spend money to get them overfat. Also, remember that cows that are too thin or overfat have welfare issues.

“If you want to take better care of the calf, take better care of the cow,” said Abney.

Think about the calf she is carrying while also feeding a calf on the ground.

“You’ve got to get these animals bred. That is all that matters,” said Abney.

Skinny cows don’t cycle well, struggle to get pregnant, don’t milk enough and don’t last as long in the herd.

“Fetal programming is real. What happens to that cow nutritionally will cause good or bad things to happen to that calf its entire life,” Abney said.

Myth: Fat replacement heifers are wonderful

Producers tend to pick out the best heifers and then overfeed them, said Abney.

Overfat heifers are harder to breed and may have dystocia issues because there is too much fat in the birth canal. They may not produce enough milk because their udders are overfat. Abney said a heifer should not be pushed to gain more than two lb. per day.

Myth: All feed is created equal

Producers need to consider the rumen degradability of different protein sources. This is the fraction of the crude protein consumed, which is broken down by rumen microbes.

Lots of ingredient options exist to supply protein, but there is a variation of 25 to 100 percent when looking at rumen degradability of different sources, said Moore.

Myth: Fat on the feed tag equals calories in the feed

Too often there is not enough information on the tag of purchased feed to make the best decision. Protein, fat and fibre content are on the ingredient lists but that may not be enough to make an informed decision in terms of digestibility or quality, said Moore.

He recommends dealing with reputable feed manufacturers and consulting with local nutritionists.

Myth: Hay is cheap and all a cow needs

Lower quality hay means lower intakes, which means the cow may not be getting enough energy or crude protein.

“I see terrible hay all the time,” said Abney.

“No matter how good you think your hay is, it probably is not.”

People may think a cow eats three percent of her body weight but that is a myth.

“There is almost no hay on the face of the earth where the cow eats three percent of her bodyweight,” he said.

Myth: That cheap hay I bought just needs some protein

Intake of lower quality forages can be boosted with added protein, but it depends what production stage the cows are at and what time of year it is.

“It was cheap for a reason. Hay that is low in crude protein is probably low in pretty much everything else,” said Abney.

Don’t assume the quality is there. Get samples tested every year because quality varies.

Myth: Creep feeding too costly

Producers may perceive creep feeding as too expensive based on past experience. Calves may have become too fleshy, there was no obvious gain in profits when the calves were sold or there was no improvement in weaning weights.

It can be difficult to measure whether the gain was economical, said Moore.

Controlled intake reduces the chances of fleshy calves. It can also improve quality grades and increase saleable weight. As well, weaning stress is reduced at the feedlot because the calves have already been introduced to a new feed.

Producers also need to think about whether a calf is already getting good nutrition from the cow’s milk and forage that is available at the time.

Some use creep feeding to give the cow a break during a drought or other situation in which feed is limited, but research says it does not really save the cow, said Moore.

Myth: Don’t overfeed pregnant cows because the calf gets too big

Calf size is probably influenced more by genetics than nutrition.

“There is some truth to that because we will make the calf bigger by taking care of the cow, but it does not lead to any incidence of an increase in dystocia,” said Moore.

A good body condition score and adequate precalving nutrition helps produce healthier calves. The cow can make better colostrum for calf immunity, leading to improved vigour and survivability.

A well-nourished cow has a better subsequent pregnancy rate and fewer post-partum days before rebreeding.

Don’t be afraid to correct the cow during pregnancy, especially if there were nutrient deficiencies during the grazing season, said Moore.

Myth: Salt blocks are a complete mineral supplement

Salt blocks are made of salt, said Abney.

The colour in salt blocks comes from colouring agents and does not represent mineral content.

A cow needs half to five eights of an ounce of salt per day but also needs additional vitamins and minerals every day.

Myth: Magnesium is the most important mineral

Magnesium is needed for energy utilization and bone growth, but absorption is affected by the amount of calcium, phosphorus and potassium in the diet.

If there is high potassium in the ground it antagonizes the absorption of magnesium. Other trace elements can be deficient in forage and may also be antagonized by the presence of other nutrients such as sulfur or iron.

“It is a balance and we can’t chase one single nutrient,” said Moore.

Magnesium is important for aged or lactating cows. Too much magnesium feeding can irritate the gut, but a deficiency is also linked to grass or winter tetany.

Magnesium can be supplemented, but it may impair intake of other free choice minerals because products like magnesium oxide in the mix tastes bitter.

“At the same time we are supplementing magnesium, we are probably giving up supplementing some of the more important aspects of a mineral program, which could be trace minerals,” Moore said.

There are deficiencies in all environments so balance is the key.

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