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CALVING COWS IN TIMES OF FEED SHORTAGE

The most important feeding period in a cow-calf operation is between calving and the start of the breeding period. This is especially true this winter in areas of feed shortage due to last summer’s drought. Cows need to be on a rising plane of nutrition after calving so that they gain weight and have their first full reproductive cycle just before or at the start of the breeding season. This is the time to feed your best winter feed. The goal is to have the majority of your cows conceive during the first three weeks of the breeding season so that they will calve at the same time each year. In addition you want to have the majority of your calves born in a shorter calving season the next year.

Several years ago we conducted a very large feeding trial at the Melfort Research Station in Saskatchewan in co-operation with veterinarians at the Western College of Veterinary Medicine to look at the effects of feeding different levels of energy prior to calving and to see how the energy feeding levels affected the calving performance the following year. At the time, the herd calved out in late February-March in sheltered wintering pens.

Prior to the start of the trial in November, our crossbred cows grazed annual cereal regrowth pasture, meadow brome or crested wheat grass regrowth. At the start of the winter feeding period all cows were gate sorted visually into two groups — a fatter group and a thinner group. The body condition scores for the fatter cows averaged 3.7 on the Canadian 1-5 scale where 1 is extremely thin and 5 is very fat. The thinner group had an average body score of 2.8.

Both groups were then subdivided into two feeding groups one being fed 80 per cent of the energy levels of the Nutrient Requirements for Beef Cattle (NRC) and the other group being fed 110 per cent of the energy requirements. Each of the four groups contained 50 cows. All cows had access to free-choice two-row barley straw, water, cobalt-iodized salt, and a mineral mix containing 70 per cent dicalcium phosphate and 30 per cent cobalt-iodized salt. In addition, all cows received two to three dry matter pounds of rolled barley grain per head per day when the average daily temperature remained below -20for more than a week at a time.

After calving, all animals received approximately 11 dry matter pounds of barley silage and 6.5 dry matter pounds of rolled barley grain per head per day, plus free choice two-row barley straw. This ration met NRC maintenance requirements for a 1,400-pound cow with superior milking ability in the first three to four months of lactation.

Increasing the cows’ energy intake by feeding more grain and silage after calving was similar to flushing, and this allowed our cows to cycle quickly and conceive on first bull service during the 42-day breeding season. As a result, our cows basically calved at the same time the next year during a short calving season.

At the start of the breeding season the thinner cows on the lower-energy ration had a body condition score of 2.2 and by the time the cows were trucked to the pasture in the spring their body condition score was 2.25 as a result of gaining weight on the after-calving ration.

In the first year of the trial, calf birth weights, adjusted weaning weights and calving intervals were basically all the same for all cows regardless of the pre-calving feeding regime. When each group of 50 cows were pregnancy checked at the start of the second year of the trial (the following November), the thinner group fed the lower-energy ration were all in calf, while the thinner cows fed the higher-energy ration had five open (10 per cent), the fatter cows fed the lower-energy rations had six open cows (12 per cent), and the fatter cows fed the higher-energy ration had four open cows (eight per cent).

We followed the same cows for three calving seasons under the same pre-calving feeding systems based on the original visual sorting of the cows in the first year. At the start of the fourth calving season, the fatter cows fed the lower-energy ration had a total of 20 open cows accumulated over the three years while all the other groups each had an accumulation of 11 open cows in total. Some of the open cows had reproductive failure due to physical problems in their reproductive track and this could not be attributed to pre-calving nutrition.

The thinner cows in our herd were efficient cows that over time could work and successfully raise a calf in our management conditions. The overly fat cows fed the lower-energy rations could not handle the management system over successive years.

The basic recommendation coming from this research trial can be most applicable to feeding systems this year, in times of short feed supply. You can reduce the amount of energy that you are feeding your cows before calving but you must have your cows on a rising plane of nutrition after calving in order to meet the NRC requirements for a nursing cow and have a successful breeding season. The reduced energy pre-calving feeding system could be implemented this year, but is not recommended on a continuing basis. Reducing feed intake pre-calving is a way to harvest extra condition off of fat cows. If the cows are thin (body condition score 2.0 or less prior to the start of winter, reducing feed intake is not recommended.

It is always recommended to have cows on a rising energy level after calving. In order to do this we recommend that every 10 days to two weeks you gather up those cows that have calved and put them in a place where you can increase their energy levels. This can easily be monitored if cows are in a feeding yard but if cows are calving on pasture move the cow-calf pairs to your best pasture area prior to the breeding season.

Alternate day feeding of the energy supplement is a labour-saving method that could help this winter. Research at Lacombe Research Centre showed that labour could be reduced by feeding two days equivalent of the energy supplement be it grain, silage or hay on alternated days when cows have free-choice access to feed straw all the time.

If you are feeding your cows in a field during the winter and feed supplies are short it is highly recommended that you feed in portable feed bunks rather than on the snow. Recent research at Lacombe Research Centre in co-operation with Barry Yaremcio of Alberta Agriculture has shown that winter feed losses can be as high as 25 per cent or greater when feed is fed on the snow compared to feeding in a portable feed bunk. The feed loss consisted of the fine particles plus grain which contained the higher nutrient content of the ration. This feed loss is extremely expensive.

In times of economic hardship in the cow-calf industry any management strategy that will reduce feeding cost will be beneficial to the bottom line. For additional information on winter feeding alternatives and ways to reduce costs take a look at We have summarized research from various sources that is applicable to your operation.

Duane McCartney is a retired forage beef research scientist from Lacombe, Alta.

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Duane McCartney is a retired forage-beef systems research scientist at Lacombe, Alta.

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