October 27, 2011
By Anibal Pordomingo
For grass-finished beef to expand into the larger consumer market in the USA it will have to become more available on a year around basis and be of consistently high quality. In Argentina, our grassfed beef supply has no more seasonality than is found with feedlot-finished beef in the USA and is known throughout the world for its excellent eating quality.
Since Argentina and the USA lie at the same latitudes and have similar rainfalls, year round grass-finished beef is just as possible.
All you need is the knowledge and the willingness to give up some of your grass prejudices.
In most cases, one cannot rely solely on native range or on introduced perennials such as fescue and orchardgrass for a year around program.
Perennial grass production follows the natural rainfall and temperature curves and ignores the demands of the consumer. On perennial grasses, spring finishing is usually the easiest and in many climates the only time grass finishing will be possible. However, if we will consider the use of winter and summer annuals the possibilities for year around production are greatly enhanced.
In the more temperate parts of the country, winter is probably the most challenging season to produce grass-finished beef on a perennial forage.
Low temperatures, reduced day length and periods of snow can make winter the season that crimps the whole year's production plan.
In most temperate environments, improved perennial pastures (legume based or not), warm-season annuals and some native grasslands have forage quality compatible with that required for finishing cattle (daily live weight gains of 1.8 pounds or above) on a seasonal basis.
In areas of the country with warm winters and cool summers, perennial pastures (mostly legume and fescue, orchard grass or perennial ryegrass) can be grazed year around and cattle finished at all times. However, such moderate areas are extremely rare in the USA where extremely hot summers and cold winters are more the norm.
In most of the USA, perennial species go dormant or slow growth in winter. This makes it impossible to maintain the forage quality and quantity necessary to finish cattle.
Stockpiling forages in the late summer and fall for winter use may be an alternative but in most cases the quality of these forages is not adequate to produce the high average daily gains needed for finishing. These leaves us with only two alternatives.
One is to use specialist forage species that will grow under low temperatures and the other is a high quality stored forage such as pasture silage.
WINTER IS EASIEST TIME TO FINISH CATTLE
Winter annuals have the quality and the energy to sustain high weight gains in winter. Actually, the best weight gains available in grass-finished cattle have been accomplished in winter with winter annual grasses.
Properly managed, the winter annual will produce two to three times more forage than a cool-season perennial in winter and can double the average daily gain available from the perennials.
Apparently, many American graziers are having a hard time coming up with grass-finished animals in the late winter and early spring due to their over-reliance on perennial forages.
In Argentina, the greatest individual gains on grass finishing programs are reached in mid to late winter on winter annuals such as cereal rye, oats, triticale or wheat.
Under restricted availability (>5% of bodyweight of available forage on dry matter basis/head day) weight gains are usually from 2.0 to 2.7 lbs/day and feed efficiencies range from 9 to 14.1 (pound of grass dry matter per pound of weight gain).
These weight gains are only matched by alfalfa/perennial grass mixes in the spring and grazed green leaf corn in the summer and fall. (Green leaf corn is corn prior to the development of the ear.)
However, not every winter annual will work everywhere. Some will winterkill in very cold temperatures. Therefore, we should select adequate species that fit our region's climate.
Cold hardiness, winter growth and growth distribution, length of vegetative period, pest tolerance and water use efficiency are the relevant issues we deal with when selecting plant materials.
It is essential to plan a reliable forage chain that can supply steady high quality from late fall to early spring. Cereal rye, triticale, annual ryegrass, oats, barley and wheat are the species from which we select cultivars to establish a forage chain in Argentina.
Keep in mind that without irrigation, a fallow period to collect moisture before planting will have to be included in your planning about winter annuals. We want to plant as early as possible so that we can build a stockpile of high quality grass before winter.
Each of the above winter annuals has a different maturity period and a different level of cold tolerance. Therefore, it is better to plant a sequence of annual forages in separate paddocks rather than rely on one or mix them together.
THE FORAGE CHAIN
In my area of Argentina, which is climatically similar to northeastern Oklahoma or southeastern Kansas, a forage chain could be planned as follows: oats, cereal rye, wheat and annual ryegrass.
These species would be planted in sequence, starting with oats and ryegrass in the late summer (August 15 in the northern hemisphere) and rye and wheat in the early fall (first two weeks of September).
About 35 to 45 days after planting, oats will be ready for first grazing, after which rye will be ready (it is the fastest grower and grows more than the others under low temperatures) followed by wheat.
At 50 to 60 days after planting, the annual ryegrass will be ready for its first grazing.
Annual ryegrass has a slower rate of growth in our conditions, compared to the others, but it is more nutritionally balanced and does not tend to shift into the reproductive stage until late spring. Therefore, it is the one with the greatest quality and offers the most flexibility in stockpiling for winter use.
Rotational grazing should always be used.
After a 30 to 40 day regrow period, the second grazing could take place. This would now most likely be mid-winter.
At this grazing, oats should be grazed first, followed by cereal rye, wheat and ryegrass.
In cold weather, cereal rye will make the most forage and oats will grow the least due to its low cold tolerance.
Annual ryegrass should be skipped entirely in this mid-winter period and stockpiled for later use.
Deferring the grazing of the small grains is not recommended because of the risk of frost kill of the leave tops. This is not usually as much a problem with annual ryegrass so it is the one we will continue to stockpile.
HIGH QUALITY STORED FORAGES NEEDED
It is very rare for stored forages to be of greater quality than winter annuals. To prevent the diminishment of the animals' average daily gain, stored forages used to supplement winter annuals must be of the very best quality available.
Our research in central Argentina has shown that the use of hays (alfalfa, mixed pasture or oats hay) with at least 60% digestibility, or silages (alfalfa based silage, mixed pasture silage, oats silage or soybean silage) with at least 65% digestibility, will not decrease the finishing gain on winter annuals even when it makes up 50% of the animal's daily intake.
Estimates of potential daily intake (dry matter basis) could be based upon 3% of the animal's body weight. In the 50/50 example cited, if an animal is capable of eating 13 lbs of dry matter a day, it would be getting half of that in the form of stored forage and the other half in direct-grazed grass.
In our work, we have offered diets up to 70% stored forage without depressing gains but the quality and forage allocation of the grass must be such that the animal has great selectivity. This allows the animal to offset the lower quality of the stored forages by only eating the very best of the grass sward.
Weather emergencies can lead to the need of feeding a diet of nothing but stored forages. We have achieved average daily gains of 1.6 pounds per day on nothing but stored forages.
Such stored forages must have been cut when the grass was high in leaf and soluble carbohydrate (afternoon cutting). Preserving leaves and the soluble carbohydrate content are key factors in determining quality of stored forages.
LUSH FORAGE PROBLEMS
Occasionally, animal performance on winter annuals could be quite low on the first grazing. Nutrient imbalances (excessive nitrogen, low soluble carbohydrates) and excessive water content are at least partially responsible for this result. It has been suggested that on lush forages with a dry matter of less than 18%, the addition of fibrous materials to the diet would help to reduce watery feces and improve gains.
Although this will help reduce scouring, there is no evidence of true gain improvement from feeding low-quality hays. On the other hand, feeding high quality hays will increase gains.
Keep in mind, that the inclusion of only 15 to 20% hay is all that is necessary to correct the low dry matter.
However, rather than relying on hay, it would be far better to correct the root causes of this problem.
The high use of nitrogen fertilizer, high soil moisture, and high temperatures during the first 40 days after seeding favor the conditions that create such imbalances. These conditions usually occur in the late fall or early winter and at the first grazing.
Counteractive measures are to delay grazing lush forage as much as possible (at least 45 days after planting).
Feed good quality hay or mixed pasture silage free choice with no restrictions.
Mow and graze the windrows a day later.
Plant species with a slower initial growth (oats or wheat vs cereal rye).
Plant species that stockpile with good quality (annual ryegrass vs cereal rye).
Reduce or eliminate nitrogen fertilizer use at seeding time.
Use no-till planting if possible. This results in less soil nitrogen being available at the early stage.
Supply high-energy, low-moisture supplements such as dried molasses or beet pulp up to 0.75%of body weight level (dry matter basis) to promote better nutrient balances.
Once the weather finally turns chilly, these imbalances will disappear and these high quality forages will express their greatest potential.
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