By Fred D. Bisplinghoff, D.V.M.
The utilization of animal proteins in animal feeds over the past 30 years has not been a smooth journey, but one that has experienced many challenges and changes in production and marketing. I will address some of the events and I am sure many readers will recall others I have missed.
Meat and Bone Meal
By the early 1950s, the rendering industry had switched their processing systems from wet rendering to dry rendering in batch cookers, which permitted the industry to produce a meat and bone meal (MBM) with a superior nutrient value. In the 1970s, the industry converted to continuous rendering, which improved throughput and allowed renderers to process raw material more quickly.
MBM has always been well received by poultry nutritionists, and as the poultry industry grew, MBM paralleled that growth. Because of research conducted by the Fats and Proteins Research Foundation that demonstrated the high availability of MBM’s amino acids and phosphorus for poultry, nutritionists increased usage of MBM in all types of poultry rations in North American and foreign countries. In contrast to 30 to 40 years ago when domestic poultry rations utilized 15 to 25 percent of the MBM fed to animals, poultry rations today could account for over 50 percent of the North American MBM feed usage, 90 percent or more in Southeast Asia, 55 percent in China, and 95 percent in Middle Eastern and African countries. Poultry are the renderers’ best friends.
Until the large scale production of solvent extracted soybean meal in the late 1930s, MBM was the primary protein ingredient in swine rations. In the 1950s, research supported by the soybean industry at the University of Illinois and universities in other soybean-producing states advocated removing MBM from swine rations and grow and finish hogs on a corn-soy diet.
Even with an improved product, renderers experienced lower inclusion levels over the years. Much of the reduced usage was due to exaggerated and unfounded statements by veterinarians, university extension personnel, and nutritionists. They raised a perceived health issue with swine producers by associating MBM with swine diseases (i.e., salmonellosis, pseudorabies). Research at Iowa State and Purdue University discredited all of these unsubstantiated statements and articles, but the negative perceptions still exist.
In 2001, one of the main challenges for renderers is to improve MBM’s usage in swine rations by conducting more research on swine health issues, processing raw material at the proper temperature, and producing a more uniform and consistent product, regardless of the daily variations of raw material mix.
Some feed manufacturers have included MBM in their dairy and beef concentrates as far back as the 1950s. In the 1970s, the industry saw increased levels of MBM being fed as a sole animal protein ingredient or in combination with other animal proteins (i.e., feather meal, blood meal, and poultry by-product meal) as an excellent by-pass protein source for growing cattle and lactating dairy cows. This market accounted for approximately 15 percent of mixed-specie MBM fed to animals until the ruminant-to-ruminant feeding ban in 1997. Pork meal is still being formulated in cattle rations, but the level of animal proteins being fed to ruminants has declined significantly in recent years.
A major difference in MBM marketing in the 1960s and 70s versus today is the substantial specific specie premiums being paid for pork meal for ruminant rations and lamb meal for pet food.
One of the most rewarding MBM success stories has been the dramatic increase in exports in recent years. In the 1950s, 60s, and 70s, MBM exports were less than 100 million pounds per year compared to approximately one billion pounds in 2001. The acceptance of this high protein product with excellent phosphorous availability has enabled renderers to receive a competitive price in relation to 48 percent soybean meal.
Blood Meal
Until the era of the batch cooker, blood meal was processed with other animal raw material, or if processed separately it was typically added back to wet rendered tankage to produce 60 percent protein digester tankage. When renderers and packers began to dry blood in dry rendered batch cookers, they produced a high protein feed ingredient but they degradated and bound many of the essential amino acids, especially lysine, which reduced their availability. This was due to the extended cooking time as it was difficult to evaporate the high water content in a dry rendered cooker.
In the 1960s and 70s, ring drying and spray drying processing was introduced along with new technology to coagulate the raw blood and separate the red corpuscles from the serum. Ring dried blood’s primary market was animal feed, while the outlet for the spray dried meal was initially as an adhesive in the plywood industry and then later in pig starters and aquaculture rations due to the excellent availability of its amino acids. Until recently, serum (plasma) was discharged in the wastewater stream. Today, it is concentrated and spray dried into a value added ingredient for pig starters and other young animal rations. Dried blood plasma was only the forerunner of many new value added blood products.
Poultry By-Product Meal
One of MBM’s major growth areas in the 1950s and 60s was the expanding dry pet food market (30 percent of MBM feed usage in 1980). But as pet food nutritionists began to seek alternate ingredients with higher protein content, lower ash, and improved palatability, poultry by-product meal (PBM) became the predominant animal protein ingredient in premium companion animal rations.
Feed grade PBM is still extensively formulated in poultry rations, but more poultry processors are separating raw material to produce pet food grade PBM. Regular pet food grade PBM’s ash content is approximately 17 to 18 percent, but by separation of the bone faction from the meat meal by air classification, screening, or other methods, renderers could produce PBM with less than 14, 12, and 10 percent ash. The lower ash meals allowed nutritionists to produce pet rations with the optimum calcium, phosphorous, and magnesium levels to assist in controlling urinary calculi, plus improving the ration’s digestibility.
In recent years, there has been an expanding demand for chicken meal (CM). It contains broiler parts that have no, or a minimal, edible market (i.e., backs, necks, condemned parts). CM is formulated in premium pet foods, which is the fastest growing pet food segment, while similar poultry meals, such as turkey by-product meal and turkey meal, find limited usage in premium pet food formulas – they are primarily sold as PBM.
As with MBM, PBM has participated in an expanded export market. It is included in multiple specie feeds, as in North America, but in Asia it is used more extensively in aquaculture rations as a fish meal replacement.
Feather Meal
It is possible that hydrolyzed poultry feathers had the most difficulty of acceptance of any animal protein. After World War II, when the broiler and turkey industry expanded, renderers were confronted with the challenge of disposing of feathers. They had little nutrient value in the raw ground state, but nutritional value increased dramatically by partially hydrolyzing the keratin protein under pressure, with subsequent drying. In the 1940s, 50s, and 60s, producers of feather meal (FeM) encountered a great deal of resistance from feed nutritionists because of its inconsistent digestibility and its lower level of certain amino acids, particularly methionine and lysine.
The acceptance of FeM as a viable protein ingredient is probably the foremost success story of animal protein research. Research at the universities of Georgia, Guelph, North Carolina State, and Clemson demonstrated that FeM, with its high cystine content, which can provide one-half of the total sulfur amino acid requirements in poultry rations, could be used at reasonable levels in all types of poultry feed, particularly layer and broiler breeder diets.
Studies at the University of Georgia showed a higher metabolizable energy value for FeM than was assigned in scientific publications. This work increased FeM’s value in poultry and other monogastric diets. Another milestone in recent years was research trials at the University of Nebraska, which illustrated FeM’s value as a by-pass protein ingredient when fed as the only animal protein or combined with other animal proteins, particularly blood meal. FeM is formulated extensively in beef cattle liquid supplements and range blocks.
Research at the University of Guelph, Ohio State University, and other universities had repudiated old research data that assigned animal proteins, particularly FeM, low digestibility levels in aquaculture rations. In 2001, all rendered animal proteins, MBM, PBM, FeM, and bone meal, have excellent inclusion in aquaculture rations all over the world.
Raw Meat and Bones for Small Animal Rations
Raw meat and bones can trace their introduction into pet food when canned dog and cat food companies switched from a primary vegetable (i.e., barley, rice) with processed MBM formulas, to rations that were based on deboned red meat. Renderers responded to this new market by supplying quality muscle meat from fresh fallen animals. The animal was skinned, offal removed, carcass chilled, and muscle meat removed and frozen. Frozen red meat provided extra income for many renderers, but in the late 1980s, pet food producers replaced much of the red meat with ground and chilled poultry offal. The raw poultry offal was competitively priced, easier to unload, store, convey to mixers, and there were less rejections. Today, only large-volume fallen animal renderers can participate in this competitive market.
One positive area for red meat is the increased numbers of racing greyhounds that consume up to one-and-a-half pounds of muscle meat a day. Breeding animals and growing pups are also a very good outlet. Meat for greyhounds commands a premium price and only a few renderers can meet the strict specifications set by the owners and trainers.
Raw red meat and bones have been the major dietary ingredient in semi-moist pet rations since they entered the market. With improved cooking and extrusion technology, the pet food industry is endeavoring to increase the sales of semi-moist foods by using a great variety of animal meats (i.e., chicken, lamb, venison, turkey). Another raw product usage is pet treats, which have become a high premium blockbuster business over the past five years.
A worthwhile project for the rendering industry is to determine the volume and trend of edible and inedible raw poultry and livestock parts that are removed from the rendering stream and formulated as an ingredient in small animal diets or sold as pet treats.
August 2001 Render