Megacalories. Nutritionists measure the quality of pasture in Megacalories of energy (Mcal). The more energy that is available in the sward, the more Mcals the animal gets with each bite. As the grass matures, its protein and energy content decrease, and its fiber (cellulose and lignins) increases. This change reduces the nutrients and energy available with each bite. Pasture energy can range from lows of 0.1 Mcal per pound (0.22 Mcal per kg) of feed, up to highs of 0.8 Mcal per pound (1.76 Mcal per kg). The energy is always highest in plants that are young and vegetative, and that have not begun setting seed yet.
Cool-season grasses are higher in energy than warm-season grasses. This is because warm-season grasses have a thickened outer wall, or sheath, around the nutritious inner cells, which helps protect the plant from desiccation during very hot weather.
As energy is reduced, the animal must increase how much it eats to meet its needs — but at the same time the food, being more fibrous and less digestible, is passing through its system more slowly. This is the double whammy: The critter needs more food but can only eat less.
Impact on Animal Production. A study done by the Forage Systems Research Center at the University of Missouri illustrates the impact of forage quality on animal production. Between 1982 and 1985, researchers examined the performance of yearling steers and cow-calf pairs on two high-quality pastures (brome/red clover and orchard grass/red clover) and on lower-quality pastures of endophyte-infected fescue. (Fescue isn’t necessarily a lower-quality feed, but when infected its quality drops significantly.) On both types of high-quality pastures, the animals performed about the same, but when they were placed on the low-quality pastures performance plummeted: Average daily weight gain dropped 22 percent for the calves and 51 percent for the steers on the low-octane pastures. (The calves didn’t suffer as badly as the steers because their production was somewhat buffered by their mothers.) Conception rates (rebreeding) for the cows reflected the poorer-quality feed by dropping from 98 percent on the high-quality pastures to 74 percent on the low-quality.
The best way to obtain high-quality pastures is to grow a diverse polyculture of grasses and legumes. The grasses provide carbohydrates and the legumes provide crude protein. An ideal mix runs from 60 to 70 percent for grasses, and 30 to 40 percent for legumes. As your grazing-management skills improve, your pastures will tend to move in this direction naturally, because more even grazing of a sward leaves plenty of an open canopy, which allows the legumes to compete with the grasses.
Biological Cycles
Regardless of where you live in the country, there are predictable cycles for forage production. Grass growth begins in the spring of the year (the date of which depends on locale), and flushes in late spring or early summer. Growth usually tapers off during the peak heat of summer. Grass may have a second, smaller flush in late summer or early fall, and then becomes dormant for midwinter. (The exception are the southernmost areas of California.) Figure 14.1 shows a fairly typical growth curve.
The biocycle for mother animals peaks during early to midlactation. It tapers off during midlactation and is at its lowest point from after weaning until 2 to 4 weeks before parturition.
FARMER PROFILE
Karl and Jane North
“During the late 1970s, we spent 6 years learning about low-input farming in the Pyrenees Mountains of France. There isn’t much farming left in that area of France, but what there is, is pre–industrial Revolution type of stuff. Farmers use donkeys and hand-tools,” Karl explains.
Upon their return to the United States, the Norths purchased 60-acres of bare land in central New York State. “By purchasing bare land, we had the opportunity to build things just how we wanted them. We gave a lot of thought to how buildings should lie on the land to take advantage of the land’s attributes. We built an energy-efficient passive-solar home and three-sided, open sheds partly from trees on our land.”
The land is only about half open. The treed portion provides wind protection not only for their buildings, but also for the Norths’ flock of sheep and their workhorses. “We have one tractor that we use for plowing snow in the winter, turning compost piles, and baling hay, but we use our horses for cutting hay, raking hay, and in the woodlot.”
The Norths’ primary enterprise is a seasonal sheep dairy. Forty-five ewes lamb on pasture in early May, and are milked in a six-stanchion parlor through the end of September. The milk is then made into cheese in an on-farm cheese plant. “Although we only milk for 4 or 5 months, we are able to carry an inventory of cheese year-round, because the types of cheese we produce require long aging.”
Marketing is critical to the success of an operation like the Norths’. They market cheese, lamb, yarn, and tanned hides.
“About 60 percent of our cheese is marketed at the Ithaca, New York, farmers’ market. The market has a cosmopolitan clientele of people who can afford $12 per pound for cheese.” The rest of the cheese is marketed via mail order and an in-town outlet. The mail-order business grew out of write-ups in various magazines and books about cheese, and from taste-testings they did in New York City. “For us, mail order works. Our product is unique, and the customers are willing to pay not only for our cheese, but also for the shipping.”
Ethnic markets also help Karl and Jane with marketing their lambs, which come in May and are sold or butchered when the grass runs out in December. “With this short window, most of our lambs weigh less than 80 pounds when we sell them. One-third of our lamb crop we direct-market, but the other two-thirds are sold to a packer. Luckily, we have an ethnic packer who likes lambs this size.” Conventional packers want lambs up to 120 pounds.
“We really try to think in terms of a whole system. Holistic management has helped with that, but we were thinking that way even before we found it.” The whole-system approach helped them look at all the products they could sell from their farm, including the yarn and the hides. “What most outsiders find unique about our operation is the harmony of it, how everything works together and how energy efficient it is.”
From a week or two before parturition until 2 to 4 weeks after, the mother animal’s energy requirements are soaring, yet her physical capacity to take in sufficient feed is limited. This is caused by the pressure the developing fetus is exerting on internal organs (most women who have had children can attest to this situation), and after birth it takes a while for the digestive organs to get back to where they can handle a maximum volume of feed. If the feed she is eating at this time is low in nutrients and energy to begin with, then the mother animal is running at a big loss; to make up the loss, she eats into her reserves of fat and muscle. Figure 14.2 displays a typical mother animal’s cycle.
For breeding males, the demand peaks during the 6 to 10 weeks of the major breeding season. Growing animals have a relatively high demand year-round, if fast growth is a goal.
Energy in the forage supply must be capable of meeting the needs of stock during the various phases of life: growth, breeding, lactation, and so on. Matching the biological cycles of both animals and plants can minimize, or even eliminate, the need for supplemental feeds (Figure 14.3). This means that mother animals should be bred to calve/lamb/foal/kid, and so on, at the onset of the spring growth period for your area of the country. If you live in Mississippi, that may be March 1; in Minnesota, it’s May 1. With the possible exception of a few pockets of California, having baby animals in January or February is off cycle for most places in North America.
Numerous university studies support the profitability of getting in sync with the natural cycles. Another study from the Forage Systems Research Center showed that weaning weights for calves born in spring (after March 15) weren’t significantly lower than the weights of calves born in winter (518 versus 526 pounds [235 vs. 239 kg]). When factoring such issues as higher death loss for winter-born calves and higher expenses for feeding the cows of winter-born calves into the equation, the spring-born calves had a real profit advantage that greatly offset their slightly lower
weaning weights.
Figure 14.1. An approximate growth curve for an area of the country where grass begins to grow in early March and goes dormant by the first of November.
(Modified from David Pratt, “Cows, Grass, and Profitability,” Livestock and Range Report #961, Summer 1996.)
Figure 14.2. The nutritional needs of a mother animal during the course of a birth cycle. Production is optimized on a seasonal growth curve (see Figure 14.1) for a “best fit.” If that were done with the growth curve provided in Figure 14.1, calving would begin about 10 days into March.
(Modified from David Pratt, “Cows, Grass, and Profitablility,” Livestock and Range Report #961, Summer 1996.)
Figure 14.3. By superimposing Figure 14.2, mother’s nutritional cycle, over Figure 14.1, seasonal growth curve, you can determine the ideal time for babies to be born in your area. In this example, kidding would begin around the third week of March. Remember, you’re seeking the best fit between the two curves.
(Modified from David Pratt, “Cows, Grass, and Profitability,” Livestock and Range Report #961, Summer 1996.)
Matching Animals to the System
There are a couple of fancy words, phenotype and genotype, that scientists use to describe living organisms. Phenotype means to show a trait, and genotype means that a trait is genetically passed on.
When matching animals to a grass-based system, you want animals whose phenotype and genotype are appropriate. In other words, you don’t want an animal that has been “bred up” to require high inputs in a low-input system.
Holsteins are a perfect example: Many farmers switching to a grass-based dairy operation find that their Holsteins don’t perform very well. Smaller cows, such as Jerseys, do far better in this type of system. Smaller cows produce milk profitably without the high inputs of purchased feed supplements and extensive veterinary services that the larger cows require. Again, university studies support “small is beautiful” animals in a low-input system. They don’t produce as much but are profitable nonetheless, because they don’t cost as much to maintain.
Finding good breeding stock for a grass-based system can be a challenge. If you can’t find a farmer who has been practicing managed grazing for a while to purchase stock from, you may end up having to breed up your own line. Look for low-input animals — Hereford or Angus rather than Simmental or Charolais beef cattle, Jersey or Ayrshire rather than Holstein for dairy.
Winter Management
There are a number of approaches to winter management, depending somewhat on your climate. Many grass farmers grow an annual crop for animals to graze during the winter. In the North, where snow can become pretty deep, corn can make a good grazing crop. In more moderate climates, winter wheat is popular.
Stockpiled Forage. Some areas of the country lend themselves to grazing year-round. During the dormant season, the animals can graze stockpiled forage. If you live in a relatively low-snow-cover area of the West, this may work for you. The key to success is making sure you’ve reserved enough stockpiled forage during the growing season to hold you over. In nonbrittle environments like the eastern states, the nutrient value of stockpiled forage will drop from leaching. If you attempt to feed a stockpiled supply in these areas, you’ll need to get a few samples run for nutrient value (see appendix E, Resources) and decide on an appropriate supplementation program.
Self-Feeding Silage Stacks. Another technique that’s popular in the Midwest is self-feeding silage stacks made out in the field (Figure 14.4). One problem with this technique for small producers is that you have to harvest the crops to ensile — an undertaking that requires lots of specialized equipment. In some areas of the country, there are starting to be some contract operators available to do this for you.
“Wintering” Animals. Like people heading to Florida for the winter, some farmers are working out novel arrangements with farmers in other areas of the country to take their animals in winter. Herds are shipped south for winter and north for summer, and producers in both areas benefit.
Hay. For most small-scale producers, though, winter management involves feeding hay. Hay should be fed in various areas of the farm, to spread out fertility. Traditionally, farmers fed their hay in the same area, year after year. This results in excessive nutrient loads building up in those areas, higher leaching of the nutrients into groundwater, and higher runoff to surface waters.
Figure 14.4. In many areas, self-feeding silage stacks are an ideal way to feed animals in winter. Silage stacks are prepared at harvest, right in the fields. Animals are given access to the face of the stack by placing one strand of polywire across. As the stack recedes, the wire is moved back.
To get the most benefit from your hay feeding, spread your feeding areas around the farm, particularly on fields you take hay off. Feeding on hay fields returns the fertility to the field it came from. Although some hay may be “wasted” when you feed on the ground over large areas, that “waste” will go right back into your soil for increased organic matter, and the fertilizer value of hay fed in the field can equate to $18 per ton ($0.02 per kg) of hay fed, when you factor in the value of the hay itself, the manure, and the urine that are returned to the field.
Starting the Season
At the very beginning of the grazing season, you don’t need to subdivide — but this period is very short. We always open all the gates in late winter, and when the snow goes the animals begin moving around in a large circuit every day. They clean up leftover grass from the previous season and begin nibbling the first new shoots. If they are given a vast area during this time, which may only last 2 or 3 weeks, they don’t damage any one part of the farm.
As soon as the grass gets going in earnest, begin subdividing, or closing the gates if the farm is developed into a full complement of permanent paddocks. In this early season, the goal is to move the animals quite quickly — every day is perfect if you can manage it — so they just clip the tops of the plants.
It’s a good idea to start each grazing year with a different paddock. By alternating which paddocks you use to begin the year, you help break up parasite cycles, and you create an environment that favors plant diversity.
Sometimes, particularly in nonbrittle environments, this spring flush gets away from you. The grass comes on so quickly you can’t possibly graze it off, so cut some for hay or haylage, or just to leave on the ground as green manure.
Estimating Forage Budgets
The first process in actually developing your grazing plan is to estimate a forage budget for your farm. This budget will help you get a feel for the amount of forage your livestock will require each month of the year, and it will help you get a feel for an appropriate stocking rate for your land. Forage budgets can be based either on actual numbers or on averages. (In chapter 15, you’ll learn techniques that will allow you to fine-tune the numbers for your operation, but start out with the averages if you don’t already know actual numbers.) Typically, forage budgets are prepared during the winter for the coming year. Then through monitoring, you make appropriate adjustments during the growing season.
Creating a forage budget begins with a chart, similar to the one in Table 14.1. This forage budget is based on the Joneses’ farming operation. The forage production chart uses the following information:
The field. Give some description of each field or area on your farm. Try to group areas that have similar production.
The crop. Describe what is growing on the field.
Number of acres (or hectares) in this area. This number can be a rough estimate.
Number of permanent paddocks. If this area is already broken down into permanent paddocks, enter that number here.
Acres (or hectares) per permanent paddock. This is simply an average, so divide the number of acres in this field by the number of permanent paddocks in the field.
Average yield. Unless you know an actual value for hay equivalent (HE) in tons per acre (or in kg per ha) from your monitoring program, use the values provided in Ta
ble 14.2. In this example, we assume that the Joneses have a firm feel for production in each field, as they have been monitoring for several years.
Forage production. This value represents the total HE yield for this field in tons (kg). This figure is calculated by multiplying the number of acres in the field by the average yield. (This value is used later in other calculations and is denoted by the symbol FPHE.)
Table 14.1
JONES FARM FORAGE BUDGET — PLANNED FORAGE PRODUCTION (FP)
Table 14.2
HAY EQUIVALENTS
Notice in this example that there are about 163 tons (147,871 kg) worth of production from fields that are defined as hay/pasture. Checking the feed requirements in November–March, the time of year that hay is required in central Wisconsin, we see that it will take about 148 tons (134,266 kg) of hay for winter feed — so Gil and Jenny’s annual budget looks good for both the growing season and the winter.
Small-Scale Livestock Farming Page 28