Extended Season Grazing Versus Stored Feed for Beef Cows

Beef producers strive to reduce costs while maintaining or improving productivity. Since feed is the single largest cost in cow-calf production, strategies to reduce feed costs are of high importance to the economic success of these farms. One of the trends which has become popular in recent years is extending the grazing season. Keeping cows outside past the traditional end of the grazing season (late summer/early fall) can significantly reduce costs. Savings are found by having the animals do their own feed harvesting and manure spreading, saving machinery costs and labour, and by reducing or eliminating the amount of bedding used.

Four ways to extend the grazing season are:

  1. Stockpiling perennial forages
  2. Planting annual crops such as corn or small grains, and grazing them as standing crops
  3. Planting annual crops which are swathed, then left on the field for grazing
  4. Planting annual crops which are cut and baled, with bales left on the field for cattle to eat

Research Trial

A study conducted at the Agriculture and Agri-food Brandon Research Center by Legesse et ali compared 6 cow-calf production systems over 5 years. The British x Continental cows and their calves (288 pairs/year)were rotationally grazed for the summer on either grass or alfalfa-grass pastures. From Oct - Jan, the weaned pregnant cows (240 head/year) were allocated amongst 2 pasture and 3 drylotfeeding strategies:

  1. Pasture - stockpiled perennial forage
  2. Pasture - swathed annual crop
  3. Drylot - hay
  4. Drylot - barley silage/oat straw
  5. Drylot - barley grain/oat straw

Stockpiled perennial forages included:

  1. Oats (swathed)
  2. Siberian millet (swathed)
  3. Corn (standing or left baled)
  4. Triticale (swathed)

After the winter feeding period, but before turn out, cows which had calved at least once were placed on a common diet, in the dry lot. This diet consisted of free choice grass hay and 2.2 lbs/day of a barley based supplement. Females about to calve for the first time were fed separately on a diet formulated to meet National Research Council standardsii. Calving occurred Feb-Apr, in a barn, with post calving cow-calf pairs held in a shed lot for 1-2 weeks prior to turn out on pasture. Cow-calf pairs were rotationally grazed on grass or alfalfa pastures until the end of the traditional pasture season. After this cows were either sent to a dry lot and fed on stored feed, or assigned to one of the extended season grazing groups, for the October - January period. Cows stayed in the same feeding system during each year of the trial.

Cow Performance

Cows on the extended grazing regimes gained less weight from mid to late gestation, and weighed less prior to calving.Weaning time cow body conditionscores (BCS) were similar among the winter feed groups. However,pre-calving cow BCS was significantly lower for extended grazing cows than dry lot cows, although the size of difference was small (BCS of 5.14 vs 5.06).

Calf Performance

Extended season grazing of dry, pregnant cows had no negative effect on the growth rate of subsequent calves, relative to those from cows which had been dry lotted and fed hay, barley silage and oat straw or barley grain and oat straw - the weaning weights of calves and their gain on pasture were similar amongst all winter feeding strategies.

Reproduction

Reproductive performance is a critical component of cow-calf production. Pregnancy rate to fixed time AI was similar among feeding groups, as was calving interval and the number of calves born. Also, the prevalence of dystocia, abnormal calf presentation and the number of calves born did not differ. This showed that beef cows can be grazed well into the fall and early winter without compromising their reproductive performance.

Herd Productivity

Overall herd productivity was similar when comparing winter drylot feeding versus extended season grazing. Calf weaning weights were similar, as were calving interval, % calves born, and % assisted births. Although extended grazing cows were somewhat lighter at calving time, this did not negatively impact their productivity or that of their calves. Interestingly, extended grazing cows had a lower culling rate prior to turn out, and a higher rate of calf survival to weaning.

Impact of Weather

Moisture is a critical factor in the growth of all crops, including perennials and annuals planted for extending the grazing season. During years when growing seasons experienced average to above average precipitation, the extended grazing cows were among the heaviest of all feeding groups (Fig.1). However, during below average precipitation years extended grazing cows were among the lightest of all feeding groups. The authors also point out that after this study, drought resulted in crop failure of planted annual crops, preventing the extended grazing of annuals trial to continue.

Snow cover can impact the ability of cows to access feed during late season grazing. In this study monthly total snowfall ranged from 20.9 cm to 9.2cm. Daily snow on the ground ranged from 9.2 cm to 21.7 cm. Research in Ontario has found that snow in excess of 25 cm can restrict the intake of grazing cows. This may be a more important consideration in snowier climates such as found in much of Ontario, compared to the drier regimes found in much of the prairies and parklands of the west.

Graph of pre-calving weight of cows on various winter feeding programs
Figure 1. Pre-calving weight of cows on various winter feeding programsa
EG=extended season grazing
HY=hay in drylot
SB=oat straw and barley grain in drylot
SS=barley silage and oat straw in drylot
aadapted from Legesse et al1

Summary

Extending the grazing season using stockpiled perennials or annual crops can reduce feed costs and reduce the labour and bedding needed for beef cows. When adequate forage is available, cows on extended seasons grazing perform as well as those fed in conventional dry lot winter systems fed stored feed. However, extended grazing season is subject to weather risk, and producers should plan alternative feeding strategies in case lack of rain or excess snow have major impacts.

i Legesse, G., Small, M., J.A., Scott, S.L., Kebreab, E., Crow, G.H., Block, H.C., Robins, C.D., Khakbazan, M. and McCaughey, W.P. 2012. Bioperformance evaluation of various summer and winter feeding strategies for cow-calf production. Can. J. Anim. Sci. 92: 89-102.
ii National Research Council, Beef Cattle Nutrient Requirements.1996.

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