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MOF&G Cover Fall 2003

  

  You are here:  PublicationsMaine Organic Farmer & GardenerFall 2003Pasture   
 The Benefits of Raising Animals on Pasture Minimize

Toki Oshima drawing
Drawing by Toki Oshima

By Diane Schivera

Editor’s note: Our understanding of the benefits of raising animals on pasture continues to accumulate, so Diane Schivera has updated this article that she originally wrote for the Dec. 2001-Feb. 2002 issue of The Maine Organic Farmer & Gardener. Grass feeding benefits the health of the grazing animals; the health of people who eat products from these animals; and the health of the environment. Grazing animals appear to be the solution to many of mankind’s problems!

Eating livestock products can benefit our health and the environment, particularly when the animals are raised on a pasture-based diet. More and more research is establishing this viewpoint. At MOFGA’s 2001 Spring Growth Conference, Joel Salatin from Polyface Farm in Virginia addressed these benefits as well as the profitability of raising animals on pasture. Profitability is particularly great, because animals that eat grass are healthier than those fed grain, so veterinary bills are lower.

Products from pasture-raised animals are healthier for you to eat than those from grain-fed animals for many reasons. Animals get more readily available nutrients from fresh pasture plants than from grains, so their products contain more vitamin E, beta carotene, conjugated linoleic acid (CLA) and omega-3 fatty acids. Vitamin E and beta carotene, the precursor to vitamin A, are powerful antioxidants that, among other functions, help our bodies cope with toxins. Conjugated lineoleic acid prevents many types of tumors and breast cancer in post-menopausal women. Dairy products from 100 percent grass-fed cows are the richest natural source of CLA, with as much as seven times more cancer-fighting CLA than ordinary milk and with far less cancer-promoting linoleic (vs. CLA) acid. (Cancer Letters, 1997; 116:121-130). A Finnish study comparing serum concentrations of CLA in women with and without breast cancer showed that women with higher CLA concentrations had lower risks of breast cancer. (Aro, A., S. Mannisto, I. Salminen, M. L. Ovaskainen, V. Kataja, and M. Uusitupa, “Inverse Association between Dietary and Serum Conjugated Linoleic Acid and Risk of Breast Cancer in Postmenopausal Women.” Nutr. Cancer 38, no. 2 (2000): 151-7) All of the nutrients mentioned above promote a healthy heart.

Fatty Acids

Omega-3 fatty acids – essential in our diets – have been linked to reductions in obesity, cancer, asthma and depression (because these acids cross the blood-brain barrier and help brain cells function).

We also need omega-6 fatty acids in our diet, and the ratio of omega-3 to omega-6 consumed is significant. Grasses have a lower concentration of omega-6 than -3, while grain has more -6 than -3. A pasture diet produces beef and other livestock products that have a ratio of omega-3 to -6 that is closer to our requirements. Products from pasture-fed livestock also are lower in fat than products from grain-fed animals.

Grass-fed meat is naturally high in vitamin E, according to Welch researchers, and this potent antioxidant keeps the meat from spoiling. This finding contradicted the hypothesis that meat from grass-fed cattle, with its more abundant and easily oxidized omega-3 fatty acids, would spoil very quickly. After two weeks of storage, grain-fed meat was brown but grass-fed meat was still red. (“Control of beef meat quality,” by Nigel Scollan, Annual Report and Accounts 2001, Institute of Grassland and Environmental Research)

Pastured broilers have higher concentrations of omega-3 fatty acids than grain-fed broilers. Eggs from pasture-fed hens have more folic acid, vitamin B12, vitamin E and carotenes – especially lutein and zeaxathin, which reduce macular (center of the retina) degeneration – than grain-fed.

Turkeys benefit even more than broilers from pasture, because they naturally tend to forage more. Pastured lamb has less fat and more protein than grain-fed lamb. Cheese made from milk produced by grass-fed sheep is higher in CLA than that from grain-fed sheep, and pastured sheep produce more milk than those fed hay and grain. (Interestingly, sheep’s milk has more CLA than milk from other mammals tested.) Milk from sows on pasture has more vitamin E and selenium than grain-fed, as does pork from those piglets. Putting rabbits on pasture results in healthier, tastier, more tender meat, according to a study funded by a Sustainable Agriculture Research and Education grant. (www.sare.org)

Beef animals that are fed either grasses of 12% crude protein or legumes of 18% crude protein, with more than 60% digestibility, and neutral detergent fiber of 58% grass-42% legumes, can produce meat with less marbling and backfat but a healthier omega-3 to -6 ratio and still be tender. (Eramus Okine, “Effects of type of finishing diets on in vitro lipogenesis and oranoleptic qualities of beef,” Beef and Dairy – Research Update 1997-1998, Alberta Agriculture, Food & Rural Development).

The nutritional content of cows’ milk increases with pasture feeding, especially from afternoon grazing (more nonstructural carbohydrates are available) and from early fall pasture (G.E. Shewmaker et al., “Diurnal Variation in Alfalfa Quality and Implications for Testing,” Western Alfalfa Improvement Conference Proceedings, June 1999). After moving cows from grass to grain, omega-3 fatty acids in milk drop markedly within about 3 to 4 months. Also, the more a cow produces while she is fed grain, the more dilute the components from grass feeding become (S.K. Jensen, “Quantitative secretion and maximal secretion capacity of retinol, beta-carotene and alpha-tocopherol into cows’ milk,” Dairy Research, 66, no. 4 (1999): 511-522).

Butter and cheeses are great sources of good fats, with up to 500% more CLA in these products when they come from pastured versus grain-fed cows, according to a Finnish study (Aro et al., op. cit.) The longer cheese is aged, the lower its level of CLA, so a mild cheddar has more CLA than a sharp. But many artisan cheeses and muenster that undergo bacterial surface ripening have more CLA than those that are not surface ripened.

The E. Coli Story

One reason pasture-fed animals – and their products – are healthier is that the animals eat more on pasture because they like it. This is their natural behavior. On the other hand, confined, grain-fed animals are subject to unnatural, stressful environments, such as overcrowding and excessive ammonia in chicken houses. Likewise, when feedlot cattle are taken to slaughter, their hides are often caked with dried manure that is difficult to remove and may contaminate the meat with E. coli 0157:H7, the bacteria that can harm people. Grain-fed beef animals have a much higher concentration of acid-resistant than of non-acid-resistant E. coli 0157:H7. The acid-resistant bacteria are a greater concern for people, because they survive more easily in the acidic contents of the human stomach, where they can cause disease. This research was done first at Cornell University (Diez, Bonzalez, T.R. Callaway, M.G. Kizoulis, J. Russell, “Grain Feeding and the Dissemination of Acid-Resistant Eschericia coli from Cattle,” Science, 1998, vol. 281, pgs. 1666-1668), then repeated at the USDA Meat and Animal Research Center in Nebraska (Scott, T., T. Klopfenstein et al., 2000 Nebraska Beef Report, pgs. 39-41, published by USDA).

When animals are fed a diet that is heavy in grain, undigested starch accumulates in the colon, ferments and increases the acidity of the colon contents. E. coli bacteria growing in this acidic environment develop a high level of acid resistance, then become more infectious to humans. If the animals are fed hay or pasture, even for just five days prior to processing, the E. coli population is greatly reduced. This research was repeated at the USDA station because feedlot owners were concerned about what the first study said about their meat. In Nebraska researchers tried many diets to reduce the acid level in the cows’ colons; the hay diet worked best.

Healthier Herds, Heartier Economies

Dairy cows raised on pasture generally have fewer foot problems than those raised on grain. Heavily grained cows have a propensity toward acidosis (a blood condition in which the bicarbonate concentration is below normal), because they cannot digest the grain easily. Acidotic cows often have liver problems, laminitis, and are generally “off feed.” Heifers raised on high grain diets accumulate fat in their udder tissue, which reduces their capacity to produce milk. An article in the Journal of Dairy Science (75(1):96-104) stated that intensively grazed cows had lower somatic cell counts than confined cows. A preliminary study done in Germany and reported in Nutrition Research (Jahresis, G., et al., 1997, 17(9):1479-1484) showed that organically raised cows on pasture had nearly twice as much CLA in their milk as did the milk from a neighboring, conventional herd.

A grain diet increased liver lesions in cattle. At a Queensland abattoir, livers were examined from 5,647 grain-fed and 621 grass-fed cattle of similar breed, age and weight, killed. Eleven percent of the grain-fed and only 0.2 percent of the grass-fed animals had liver lesions. After all losses from the various illnesses were totaled, producers lost $2.25 a head for grain-fed steers compared with $0.90 for grass-fed steers from these illnesses. (Aust. Vet. J., 59 (5) 129-32, 1982)

The improved health of pastured animals has an additional advantage: Antibiotics and other drugs are used less in these animals, so fewer antibiotic-resistant bacteria develop. A study reported in Applied Environmental Microbiology (Langlois, B.E., K.A. Dawson et al., 1998, “Effect of age and housing location on antibiotic resistance of fecal coliforms from pigs in a non-antibiotic-exposed herd,” 54(6):1341-1344) showed that pasture-raised pigs had less antibiotic resistant bacteria than confinement-raised pigs. On February 15, 1998, the entire Danish poultry industry voluntarily stopped using antibiotics as growth promoters. This “did not result in major disease problems in the flocks.” The drug-free birds consumed a bit more food (1.82 versus 1.78 kg feed per kg live bird), but they also weighed more at slaughter. Savings from not using antibiotics increased net income by 25 cents per 100 broilers. The Danish poultry industry produces more than 100 million birds per year, resulting in a net gain of 250,000 dollars; Danish consumers eat antibiotic-free chicken; and the industry is no longer contributing to the possible creation of antibiotic-resistant bacteria.

Good pasture generally supplies the most economical feed for cattle, sheep and horses during the growing season, despite the fact that intake of nutrients is usually reduced when animals feed on grasses and other hay crops in the pasture, compared with their intake from hay (because the farmer can harvest hay or haylage when nutrient concentrations are optimal, while animals that freely graze do not always eat grass at the prime time). The difference in yield is more than offset by the greater expense for labor, seed and machinery in planting, tilling, harvesting and feeding forage crops. Studies conducted by USDA in seven dairy districts showed that pasturage supplied one-third of the total nutrients consumed by the cows during the year, but cost only one-seventh of the total annual feed cost. One of the biggest problems with confinement feeding is that it involves high capital investment in facilities and equipment and large amounts of purchased supplements. Feeding in confinement costs two to six times more than allowing animals to graze their own forage. A study entitled “At the Crossroads: An Economic Comparison of Grass Based and Confinement Dairying in Wisconsin,” done by EPA’s ACE program, listed a net return of $1.19 for a pasture system and $0.73 for a confinement one. (Greener Pastures on Your Side of the Fence, by Bill Murphy, Arriba Publishing, 1987).

Following Cows with Other Animals

Another way to increase the economic return from a pasture is to follow cows with chickens a few days later. This increases the protein concentrations of the grasses in the field, and the chickens eat the fly and parasite larvae, reducing the need for chemical pesticides.

Insects can seriously injure an alfalfa field during the winter. Instead of spraying the fields with insecticides, scientists let lambs graze the winter stubble. The lambs removed the insect problem and increased the hay crop by 14% over untreated land and 24% over fields treated with the insecticide Lorsban. (Guerrero, J.N., et al., J. of Animal Science, Vol 80, Supplement 2, p. 126. “Grazing lambs control insects in alfalfa”)

Environmental Benefits of Grazing

The Institute for Environmental Research and Education showed a gain of one-half ton per acre per year of carbon on land that is converted from tilled cropland to grassland. Native or planted grasses remove CO2 from the air by photosynthesis and store it in the soil as organic matter or rotting plant parts. This process, known as sequestering, reduces greenhouse gases. Grassland ecosystems evolved with animals and produce a natural flow of nutrients. Grazing promotes the return of native plants – including red and white clover – and dairy cows that graze on fields with more than 20% red clover have a significant increase in the concentration of CLA in their milk.

The environmental impact of livestock production is reduced with pasture-raised animals: Less fossil fuel is required to raise and harvest feed or spread manure. With grain-based systems, more animals are kept than otherwise could be supported by the farm without purchased feed and supplements. The resulting excess manure applied to the limited land area of a farm overwhelms the soil ecosystem, and leached nutrients pollute.

Earthworm numbers in the soil of a permanent pasture system are much higher than in one rotated with field crops. This is just another good indicator of the positive environmental impact of pasture-raised livestock

About the author: Diane is MOFGA’s assistant technical director. You can reach her at the MOFGA office at 568-4142 or at dianes@mofga.org. Some of the information in this article came from http//eatwild.com, the web page for Jo Robinson’s book, Why Grass-fed is Best (Vashon Island Press, 2000).

    

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