Forage-Fed Beef Production

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1 Spring 2012 INSIDE THIS ISSUE: FORAGE-FED BEEF COMPOSITION: CHOLESTEROL AND- FATS Forage-Fed Beef Production Forage-Fed Beef composition: cholesterol, fats, and fatty acids FATTY ACIDS 2 SUMMARY OF PUB- LISHED DATA ACADIANA CATTLE PRODUCERS FIELD DAY GREEN MANURE SOYBEAN IN ROTA- TION WITH SUGAR- GANE OBSERVATIONS ON CROSSBREEDING RESEARCH IN BEEF CATTLE SPECIAL POINTS OF INTEREST: 2012 Acadiana Cattle Producers Field Day Iberia Research Station Jeanerette, LA Saturday, May 5, :00 a.m. 1:00 p.m. Registration starts at 8:00 a.m. Program starts at 8:30 a.m. Cholesterol and Fats Contrary to what many people believe fat and cholesterol are necessary for the human body to function. Cholesterol is found in foods of animal origin (integral part of the cell membrane of animal tissues), so there is no such thing as cholesterol-free beef, poultry or pork. Cholesterol is an integral part of corticosteroids, sex hormones, and Vitamin D. There is a group of fatty acids (the building blocks of fat) that are essential, which means that our body can t synthesize them and, therefore, we need to consume them in our diet. They are needed to produce many compounds such as prostaglandins, among others. We are all aware that blood cholesterol in humans should be below 200 mg/ deciliter, but we are also aware that there are two types of cholesterol (wrongly named but popular and easy to understand) which are called lipoproteins: Low-density lipoprotein (LDL) and High-density lipoprotein (HDL). The liver is our processing plant for cholesterol. Low-density lipoprotein carries cholesterol from the liver to the rest of the body. So if there is too much of it, it will be deposited in the wall of arteries. This is why it is called bad cholesterol. Highdensity lipoprotein carries cholesterol from the blood back to the liver for elimination from the body and is, therefore, considered good cholesterol. Continued on page 2 Group of steers on winter grasses. In forage-fed beef production grasses and legumes are integral part of the animal s diet.

2 Page 2 Forage-Fed Beef composition: cholesterol, fats, and fatty acids Continued from Page 1 Fatty acids Fatty acids are classified by the number of carbons, and the number of double bonds (0, 1, 2, or more), as well as the double bond location and configuration (cis or trans). The main types of fatty acids are: saturated (no double bonds), trans-, monounsaturated (1 double bond), and polyunsaturated (more than 1 double bond). In each of these types there are many different fatty acids. Studies have demonstrated that saturated fats (SFA), as a group, raise total blood cholesterol. However, there is a need for several distinctions: stearic acid (18 carbons no double bonds) does not elevate blood LDL cholesterol level and is considered neutral. On the other hand, consumption of diets rich in shorter-chain, saturated fatty acids like lauric (12 carbons, no double bonds), myristic (14 carbons, no double bonds), and palmitic (16 carbons, no double bonds) acids increase blood LDL cholesterol and are considered cholesterol-elevating or hypercholesterolemic. In the past few years we have heard a lot about use of trans fatty acids and how bad they are for our health (they have a more negative effect on blood cholesterol than saturated fats), reaching the point of being banned from the menu of restaurants in some US cities. They are produced by the hydrogenation (rupture of double into single bonds) of unsaturated vegetable oils and are found in margarines or processed foods. The hydrogenation process increases shelf life. Beef, lamb, cheese, etc. also contains trans-fats which are naturally produced in the animal s rumen (end product of fermentation process). You may have heard about conjugated linoleic acid (CLA). It is not one fatty acid but a group of them that differ in the position of the double bonds and their configuration. The CLA was found to act as a growth factor, a fat-to-lean repartitioning agent, anticarcinogenic, and hypocholesterolemic and with antiatherogenic properties. The predominant CLA isomer is rumenic acid which is produced naturally in the rumen representing about 90 percent of CLA present in milk and 75 percent of CLA present in beef fat. Another major trans-fatty acid in most ruminant products is vaccenic acid (18 carbons, 1 double bond at carbon 11 with trans configuration), which can be converted (in our cells) to CLA. Monounsaturated fatty acids (MUFA) contain one double bond. Oleic acid (18 carbons, 1 double bond at carbon 9 with cis configuration) is the predominant fatty acid in ruminant animal products and comprises from percent of the total fatty acids present. Consumption of diets rich in monounsaturated fatty acids increases good (HDL) and lowers bad (LDL) cholesterol levels. In recent years the nutritional importance of the omega-3 fatty acids, and the omega-6:omega-3 (n-6:n-3) fatty acid ratio in the human diet has aroused great interest. There is increasing evidence that n-3 polyunsaturated fatty acids (PUFA) play a major role in human health and development. It has been suggested that these fatty acids, specifically eicosapentaenoic acid (20 carbons with 5 double bonds) and docosahexaenoic acid (22 carbons with 6 double bonds), are involved in the development of brain and retinal tissues and progression and prevention of human diseases, including heart disease and some cancers. An increase in the consumption of n-3 fatty acids has been recommended to overcome the imbalance in the ratio of n-6: n-3 PUFA in current diets. Meat, fish, fish oils and eggs are the only significant sources of n-3 PUFA with 20+ carbons for human diets. Meat has lower concentrations of these fatty acids than oily fish. However, since fish consumption is low and beef accounts for an important proportion of the meat in typical USA diets, it is important to enhance the levels of these fatty acids in meat. Continued on page 3

3 Page 3 Forage-Fed Beef composition: cholesterol, fats, and fatty acids Summary of published data Beef s cholesterol content is similar to other meats (beef 73 mg/100 g; pork 79mg/100 g; lamb 85 mg/100 g; chicken 76 mg/100 g, and turkey 83 mg/100 g), and can therefore be used interchangeably with white meats to reduce serum cholesterol levels in hyper-cholesterolemic individuals. Continued from Page 2 Forage-finished beef tends to produce a more favorable SFA composition. Two of the considered cholesterol-elevating fatty acids such as myristic and palmitic acid, are usually higher in grain-fed beef as compared to forage-fed beef. Forage-finished meat contains elevated concentrations of stearic acid, the only saturated fatty acid with a net neutral impact on serum cholesterol. However, little is known of how forage-finished beef would ultimately impact serum cholesterol levels in hyper-cholesterolemic patients as compared to grain-fed beef. Forage-fed beef provides a higher concentration of vaccenic acid, an important MUFA for de novo synthesis of conjugated linoleic acid (synthesis in our body). In terms of PUFAs, a healthy diet should consist of roughly one to four times more omega-6 fatty acids than omega-3 fatty acids. The typical American diet tends to contain 11 to 30 times more omega -6 fatty acids than omega -3, a phenomenon that has been hypothesized as a significant factor in the rising rate of inflammatory disorders in the United States. It is interesting to note that the primitive human diet had a 1:1 ratio. There are significant differences in n-6:n-3 ratio between forage-fed and grain-fed beef, with an overall average of 1.53 and 7.65 for forage-fed and grain-fed, respectively. Finally, on a per-serving basis, conjugated linoleic acid content is similar among forage-fed and concentrate-fed beef but vaccenic acid, which as indicated before can be converted to conjugated linoleic acid, content is four-fold greater for forage-fed beef. Omega-3 PUFA content per serving is also higher in forage-fed beef. However, levels are low (45 mg/serving) compared to other sources of omega-3 PUFA (chinook salmon, 1821 mg/serving and bluefin tuna, 1415 mg/serving). Dr. Guillermo Scaglia gscaglia@agcenter.lsu.edu Forage-fed beef can be part of a healthy diet.

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5 Page 5 The Use of Green Manure Soybean in Rotation with Sugarcane The practice of growing soybean during the fallow period between sugarcane production cycles dates to the early part of the 20th century in Louisiana, when soybean was grown for hay production or plowed down as green manure. With the more recent advent of glyphosate-resistant soybean, sugarcane growers aggressively embraced the opportunity for economic returns from the harvest of soybean as a cash crop. Growers may also benefit from the rotation effect, which may include improvements in organic matter, soil fertility and water-holding capacity and also may aid in the disruption of pest cycles and the reduction in soil erosion. A series of experiments were conducted on different soil types and organic matter content to evaluate plant-cane yield response to incorporated soybean green manure. Treatments included were: plant-cane grown after a conventional fallow without N fertilizer; plant-cane grown after a conventional fallow with N fertilizer; plant-cane grown after green manuring without N fertilizer; and plant-cane grown after green manuring with N fertilizer. Measurements of soil inorganic N levels were made prior to spring fertilization to associate soil N levels with treatment response. Neither plant-cane yields (cane and sugar) nor recoverable sugar levels (TRS) were significantly affected by the addition of soybean biomass to the soil in the fall. Surprisingly, the additive effect of the combination of incorporation of green manure and additional fertilizer N did not result in higher plant-cane yield or TRS compared to the unfertilized plant-cane after fallow. While there were site differences for soil NH4 +_ N and NO3 -_ N concentrations, differences between treatments within sites for soil inorganic N levels were not meaningful. It seems justified to conclude that soil N was not a limiting factor for plant-cane growth and development, as there was a slight tendency for the unfertilized plant-cane following a conventional fallow period, expected to be the least N-rich environment, to yield the highest (see chart below). Failure of sugarcane to respond to applied N indicates the capability of the fallow period to make N readily available in quantities sufficient for plant-cane growth. Dr. H. P Sonny Viator sviator@agcenter.lsu.edu Soybeans are typically planted in multiple drills on sugarcane row beds during the fallow period.

6 Page 6 Observations on Crossbreeding Research in Beef Cattle The first job I had ( ) in the LSU AgCenter was to gather and analyze 32 years ( ) of crossbreeding research data from all the southern states. The data included nine breed types and we predicted birth weight, preweaning average daily gain, and weaning weight performances of approximately 150 breed combinations. Dr. Don Franke and I produced a technical bulletin from the 72,000 records we put together in this project (a digital copy of the bulletin is available upon request). Unique to these data was the inclusion of Brahman, due to a recognized need for tropical adaptation to the southern environment and particularly that of the Gulf Coast states. We are now 30 years later. Does anyone seriously doubt that many breeds have changed dramatically during the latter 30 years? Remember some of the advertisements about elephants and Angus cattle that were in the press during the 1990s? Much of that criticism arose from the use of Continental-breed (Simmental, Charolais, Limousin, etc.) sires on commercial cow herds to dramatically increase calf weaning weights. Cow-calf producers were keenly aware that sale receipts were generally based upon calf weight at market and meat quality was considered less important. Several research projects, however, have indicated a loss of meat tenderness and marbling coincidental to the use of Continental breeds and that English breeds (Angus, Hereford, Shorthorn, etc.) produced a higher quality meat product. Since that time, the industry has focused more on producing heavy calves with tender, adequately marbled beef products. Grid marketing is now an option for selling heavy beef and there is more emphasis on the type of calves produced by cow-calf producers. The advent and use of accurate expected progeny difference (EPD) estimates has supplied breeders with the tools to vigorously select animals with specific traits (lighter birth weight and heavier weaning weights, for example). It is worth noting that the earliest EPDs were for growth traits. The latest report from the USDA Meat Animal Research Center has indicated that Angus has caught up and that weaning weights are now similar for Angus and some Continental breeds. Not only have weaning weights changed among breeds, but several Continental breed associations now have black-hided artificial insemination (AI) bulls. Perhaps more importantly and again based upon recent USDA Meat Animal Research Center reports, marbling in some of the Continental breeds is now equal to that of Angus. Yes, breeds have changed over the years and breed comparisons made in the era may not be applicable today. Recently there has been considerable discussion in the national press (e.g., BEEF, Drovers Journal and Angus Beef Bulletin) regarding the merits of crossbreeding in commercial beef herds. The discussion is regarding the calf and not the cow. Crossbred cows are more productive. Certainly there are considerable benefits associated with planned crossbreeding, but there are also a few negatives. The biggest negative associated with crossbreeding is that it generally isn t a planned program and results in the mongrelization of many herds in the Continued on page 7 southern A Braford-sired calf out of a Brangus dam. Approximately one month following October weaning in Weighed 650 pounds at weaning (233 days old). region.

7 Page 7 Observations on Crossbreeding Research in Beef Cattle Continued from Page 6 How many times have we said or heard a neighbor say, when considering a bull purchase, I just don t know what breed of bull I should buy. Crossbreeding in a commercial herd requires considerable forethought, particularly for those individuals that are retaining replacement heifers. It generally requires at least two breeding pastures for an extended crossbreeding program which adds a level of complexity in the management of a cow herd. As mentioned before, there is increased demand for beef quality in terms of meat tenderness and marbling. English breeds have traditionally enjoyed the reputation of provided excellent meat quality in calves. Continental breeds have traditionally enjoyed the reputation of providing excellent growth in calves. But now, we have English breeds with excellent growth potential and continental breeds with excellent meat quality. Breeders are asking if the complexities of a crossbreeding system are necessary if they can produce growthy calves that will hang a high quality carcass by using a single breed or breed type (English, Continental). It is a very good question. What many beef producers may forget is that crossbreeding can ultimately result in crossbred cows and maternal heterosis (hybrid vigor) and is too valuable an effect on cow reproductive performance and mothering ability to be forfeited. Also, heterosis affects other lowly heritable traits that are important to the health of animals. Important to Gulf Coast producers are the heat tolerance and pest resistance traits provided by Brahman and other tropically adapted breeds that are necessary for production in our subtropical environment. Meat quality is an issue in Brahman-influenced cattle. Research conducted by Dr. Franke showed that there is as much genetic variation for meat tenderness in Brahman as in other breeds. Selection for tenderness in Brahman can overcome the meat quality issue, but it isn t immediate and will require breeder focus and time to achieve. There is also thought that genetic variation for heat and pest tolerance (resistance), the hallmark of the Brahman breed, may also exist in some Continental cattle breeds. Selection can be a rather slow process requiring the necessary tools (such as EPDs for specific traits) and several generations to achieve a significant genetic change in a trait. An alternate approach has been crossbreeding. We can consider the combination of breeds possessing specific characteristics, such as a tolerance of our subtropical climate that is passed on to the next generation. This is the concept of complementarity. Going back to the 1860s, Brahman cattle were imported to the United States and used as draft animals in plantations across the South (but specifically at some near St. Francisville, LA). The imported animals withstood the rigors of our subtropical environment and when mated to native cows produced calves of acceptable beef conformation. More importantly, those calves were also tropically adapted. Continued on page 8 A Bonsmara-sired calf out of a Brangus dam. Approximately one month following October weaning in Weighed 596 pounds at weaning (221 days old).

8 VOLUME IBERIA RESEARCH 1 ISSUE 1 STATION NEWS SPRING SPRING Page 8 Observations on Crossbreeding Research in Beef Cattle The question that has occurred to many animal breeding professionals has been Continued from Page 7 Are there other cattle breeds from around the world, that exhibit adaptability to a tropical environment and may also possess excellent meat tenderness? It is one that occurred to me, because of the quicker impact potential it may have in our Gulf Coast cattle herds. A study, conducted here at the Iberia Research Station, sought to examine the merits and negatives of introducing new genetics (Africaner) into a commercial herd. The research has examined the preweaning, weaning, postweaning, feedlot, carcass, and meat quality traits of various crossbred types. This research has also examined the reproductive performance and calf production of first-calf cows (heifers). Two tropically adapted sire breeds, Braford (Brahman-influenced) and Bonsmara (Africanerinfluenced) were used on Brangus (Brahman-influenced) cows. Also, Hereford and Bonsmara sires were used on both Angus and Brangus cows. This research has been completed. Reports will be generated for the public in the coming year. I hope I ve given you some appreciation for why we conduct crossbreeding research and why we need to do so periodically given that breeds are always changing in their characteristics. Also, I hope that you will look forward with anticipation as I make available the results of our recent crossbreeding research. The LSU AgCenter is always looking for ways in which we might exploit genetic variation in beef cattle in such a way as to provide a better product and for the economic well-being of our cattle producers. Dr. Wayne Wyatt WWyatt@agcenter.lsu.edu Visit our Website at: IBERIA RESEARCH STATION Iberia Research Station 603 LSU Bridge Road Jeanerette, Louisiana Phone: Fax: SViator@agcenter.lsu.edu Dr. H. P. (Sonny) Viator Dr. Guillermo Scaglia Dr. Wayne Wyatt Camelia Soprano The LSU Agricultural Center is a statewide campus of the LSU System and provides equal opportunities in programs and employment.