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Previous issues of the BEEF Cattle letter

Issue # 929

April 1, 2015

Increasing the Digestibility of Forages = Economic Benefits! - Francis L. Fluharty, Ph.D., Research Professor, Department of Animal Sciences, The Ohio State University (originally published in the March issue of The Ohio Cattleman and presented at the Ohio Beef Expo on March 20, 2015)

Despite the decline in prices over the past year, feed costs remain the majority of the expense of maintaining a beef cattle operation. Corn prices remain around $3.60 to $3.70 per bushel as I write this. This averages 6.5 cents per pound, or $130 per ton. Dried distillers grains are currently in the price range of $190 to $210 per ton, and the price of corn gluten feed is keeping pace on an energy and protein basis, at approximately $150 to $160 per ton, so there are no cheap supplemental feeds for cow-calf producers or stocker cattle operations. Therefore, forage-based operations must utilize cost effective management tools that maximize forage digestibility.

However, the conversion of fibrous forages to meat and milk is not efficient with only 10 to 35% of the energy intake being captured as net energy to the animal. This is because 20 to 70% of the cellulose may not be digested (Varga and Kolver, 1997). I can't imagine anyone buying grain and then throwing more than half of it away. However, we do just that with hay when we make it, store it, and feed it in a way that results in only a 10 to 35% digestibility (and we're not even talking about the waste that occurs with round bales that are stored and fed improperly, resulting in spoilage!).

In ruminants, feed is digested in the rumen by ruminal bacteria that attach to the surface of a feed particle to digest it. In ruminants, maintaining the visceral organs (rumen, reticulum, omasum, abomasum, small intestine, and large intestine) plus the liver and kidneys can take as much as 40-50% of the energy and 30-40% of the protein consumed in a day. Forage diets that are very bulky are only 40-60% digestible. More mature, less digestible forages increase the weight of the digestive tract, because more undigested feed remains in each segment of the digestive tract, causing the visceral organs to grow. Additionally, in contrast to cattle being fed grain-based diets, the size of the rumen limits the amount of energy that can be consumed with forage-based diets, and digestible energy intake decreases with increasing forage maturity. Combined, these factors increase an animal's maintenance energy requirements, leaving fewer nutrients for production purposes.

The impacts of improper forage management include cows in poor body condition, delayed rebreeding times, lower conception rates, and lighter weaning weights due to cows not breeding on the first service, and then having lower milk production than they would have had if they were in better condition. In order to reduce an animal's maintenance requirements with forage, it is necessary to use technologies that reduce the particle size of the forage, and/or increase the rate of forage digestion.

The rate, and extent, of fiber digestion in the rumen is controlled by the amount of surface area that is available for the fiber digesting bacteria to attach. From a practical standpoint with unprocessed forages, the large size of mature forage reduces the energy available to the animal, because for digestion to occur, the microorganisms in the rumen must first be associated with the forage, and then attach to the forage. Furthermore, digestion of the forage by the bacteria normally occurs from the inside of the forage to the outer layers. Limitations to the speed at which this occurs include the physical and chemical properties of the forage, the moisture level of the forage, time for penetration of the waxes and cuticle layer, and the extent of lignification (Varga and Kolver, 1997).

Anything that decreases the particle size of forages also increases the surface area for the bacteria to attach, and this speeds up the rate of digestion, allowing the animal to get more nutrients in a shorter time. The digestible carbohydrate portions of fiber, cellulose and hemicellulose must be freed from the indigestible structural strengthening component - lignin - in a timely manner to allow for an adequate amount of digestible energy to be achieved. Lignin is an indigestible compound that gives the plant strength. It limits the areas of attachment of the bacteria to the digestible portions of the fiber. This is why cattle ruminate (regurgitate and re-chew their food), to create smaller particle sizes that allow more area for bacterial attachment.

The undigested forage forms a mat layer in the rumen on the top of the rumen fluid, and this mat layer is regurgitated and re-chewed until it is either digested or reduced in particle size to a point where it can pass through the reticulum to the omasum. In many cases, the space that the mat layer takes up actually reduces an animal's feed (and energy) intake because it takes up space that a more digestible feed could occupy.

Think of 'hay belly' as a buildup of indigestible feed that must be chewed until the particle size is reduced enough for the forage to either be digested or small enough to pass on down the digestive tract. Most particles leaving the rumen are smaller than 1mm (.04 inches), although particles as large as 5 cm (2inches) may leave the rumen (Welch, 1986). It is, therefore, not hard to understand how reducing the large particle size of many mature forages to 2 to 6 inches can reduce maintenance energy expenditures due to a decrease in visceral organ mass and the reductions in energy expenditure of rumination and re-chewing. What's the particle size of first-cutting Orchardgrass or Timothy hay in a round bale . . . 3 to 4 feet? Have you ever thought of how much energy a cow needs to expend to reduce that to 2 inches?

Dr. Steven Loerch, while at The Ohio State University, investigated the potential of using processing technologies to improve the utilization of prairie hay. Dr. Loerch reported that "One effective option producers rarely consider is hay chopping. Chopping hay allows the cows to eat 25-30% more energy. Costs of chopping hay (equipment, labor, etc.) should be compared to costs of purchasing supplemental energy. For some producers, this may be a cost effective option. I came to realize the potential of hay chopping from an observation at the OARDC Beef Center in Wooster. Steers fed a chopped hay based diet gained 2.5 lbs/day while those fed round baled hay (same hay source) in a rack gained less than 1.5 lbs/day." (Source: http://beef.osu.edu/library/AltFeedSuplong.pdf).

This can be explained on the basis of more surface area being available for degradation, allowing for a more rapid rate of digestion; a faster rate of passage of indigestible components from the rumen allowing for an increase in feed intake, and the possibility that these factors allowed for an increase in propionate production due to a faster rate of digestion, and an increased rate of passage of indigestible components (Hintz et al., 1999).

Harvesting techniques have been found to result in improvements in forage digestibility. Hintz et al. (1999) reported that maceration - an intensive forage conditioning process that shreds forage thus reducing rigidity and increases field drying rates by as much as 300% by disrupting the waxy cuticle layer of the plant and breaking open the stem - resulted in an increase in surface area available for microbial attachment in the rumen, a decreased lag time associated with NDF digestion, and an increase in NDF digestion.

If forage processing is not an option on your operation, look for feed additives that increase fiber digestibility, such as Amaferm (Biozyme Incorporated, St. Joseph Misouri) or Levucell SC (Lallemand Animal Nutrition, Blagnac, France). The mode of action of Amaferm, an all-natural, non-antibiotic fermentation extract of Aspergillus oryzae is very well documented. The increase in digestion of feedstuffs by Amaferm supplementation is the result of increased numbers of ruminal bacteria and the activity of the normally occurring intestinal microflora. Calves supplemented with Amaferm have been found to have higher total ruminal bacteria counts than controls (Beharka et al., 1991), increased cellulolytic bacteria counts in beef cattle supplemented with Amaferm (Kreikemeier and Varel, 1997; Beharka et al., 1991), and higher hemicellulolytic and pectinolytic bacteria counts than controls (Beharka et al., 1991). When a greater rate of digestion occurs, more microbial protein is produced, which leads to a greater flow of microbial protein to the small intestine, possibly reducing the need for additional protein supplementation.

If forage is evaluated on a price per pound, rather than a price per ton, the necessity to maximize digestibility becomes apparent. If corn is $3.60 per bushel, it is $.065 per pound. If hay is $160 per ton, it is $.08 per pound. Normally, the digestibility of corn is around 95%, but the digestibility of long stem hay may only be 40%, so from a digestibility standpoint, the price for a pound of corn would be $.061 per pound ($.065/.95), but the price of hay from a digestibility standpoint would be $.20 per pound ($.08/.40). The main limitation in having an efficient forage-based production is the economic understanding that forage may be 3 times more expensive than grain from a digestible energy standpoint. Therefore, in order for forages to be economically competitive, they must be managed, harvested, and potentially processed to their optimum digestibility.

High prices for all feeds will necessitate that beef producers adopt grazing practices and forage harvesting and processing technologies that reduce the animal's energy and protein requirements through reducing visceral organ mass; increase the digestibility of forages through providing more sites for bacterial attachment; and use technologies and products that increase the microbial protein yield. If a producer could increase the digestibility of the hay from 40% to 55%, they would take the price of their hay from a digestibility standpoint from $.20 to $.145 per pound, a 27.5% decrease in price!

In summary, there are several options available for producers to use in order to maximize their production in a forage based operation, both with grazed and harvested forages.

Preparing Cows for Breeding - Dr. Les Anderson, Beef Extension Specialist, University of Kentucky

A successful breeding season actually begins with management decisions made at calving. Cattlemen can impact rebreeding efficiency by focusing on body condition score (BCS), early assistance during calving difficulty, scheduling a breeding soundness exam for the herd sires, planning their herd reproductive health program, and developing a plan to regulate estrus in their first-calf heifers and late-calving cows.

Reproductive management begins with evaluation and management of BCS. Body condition score is a numerical estimation of the amount of fat on the cow's body. Body condition score ranges from 1-9; 1 is emaciated while 9 is extremely obese. A change in a single BCS (i.e. 4-5) is usually associated with about a 75 pound change in body weight. Evaluation of BCS prior to calving and from calving to breeding is important to ensure reproductive success.

Rebreeding performance of cows is greatly influenced by BCS at calving. Cows that are thin (BCS < 5) at calving take longer to resume estrous cycles and therefore are delayed in their ability to rebreed. Research has clearly demonstrated that as precalving BCS decreases, the number of days from one calving to the next (calving interval) increases in beef cows. Females with a precalving BCS of less than 5 tend to have production cycles greater than 1 year. For example, cows with a precalving BCS of 3 would be expected to have a calving interval of approximately 400 days, while a cow with a precalving BCS of 6 would have a calving interval of approximately 360 days. South Dakota research illustrates the influence of precalving BCS on the percentage of cows that initiated estrous cycles after calving. This experiment demonstrated that the percentage of thin cows that were cycling in the first month of the breeding season (June) was considerably lower than for cows that were in more moderate body condition. During the second month of the breeding season, 55% of the cows with a BCS of 4 had still not initiated estrous cycles, while more than 90% of the cows in more moderate condition had begun to cycle. Thin cows need a longer breeding season, which results in more open cows in the fall. They may also result in lighter calves to sell the next year because the calves from these thin cows will be born later in the calving season.

Management of BCS after calving also impacts rebreeding efficiency. Maintenance requirements for energy and protein increase 25-30% for most beef cows after calving. Ranchers need to plan their supplementation to match or exceed this increased nutrient requirement. Rebreeding efficiency is enhanced in cows that calved thin if their energy intake is increased. Although the best management plan is to calve cows in a BCS of 5+, increasing the energy to cows that are thin at calving can boost reproductive performance.

Dystocia (calving problems) can severely delay the onset of estrus after calving. Research shows that for every hour a female is in stage 2 active labor there is a 4 day delay in the resumption of estrous cycles after calving. Early intervention helps; 16% more cows conceived when cows were assisted within 90 minutes of the start of calving. The best method is to reduce the incidence of dystocia via selection but early calving assistance will increase the opportunity of cows to rebreed.

One often overlooked management tool that can improve reproductive performance is breeding soundness exams in bulls. Ranchers need to think of breeding soundness exams as breeding season insurance. These exams are a low-cost method of insuring that your bull is not infertile. Bulls should be examined for breeding soundness about 30 days before they are turned out.

I have worked in reproductive management for nearly 20 years and it amazes me how many cattlemen still do not vaccinate their cow herd against reproductive diseases. Several diseases are associated with reproductive loss (lepto, BVD, vibrio, trich, etc). The main problem is that most reproductive loss due to disease is subtle and ranchers don't notice the loss unless they have a massive failure. Most cattlemen are not aware of their losses due to abortion. Ranchers need to work with their local veterinarian to develop an annual vaccination plan to enhance reproductive success.

Lastly, ranchers need to develop a plan to enhance the rebreeding potential of their first-calf heifers and late-calving cows. Young cows and late-calving cows have one characteristic in common that will greatly impact their reproductive success; anestrus. After each calving, cows undergo a period of time when they do not come into estrus. This anestrus period can be as short as 17 days but can also last as long as 150 days depending upon a number of factors. Typically, mature cows in good BCS will be anestrus for 45-90 days (avg about 60 days) while first-calf heifers will be in anestrus for 75-120 days. Research has shown that only 64% of mature cows have initiated estrous cycles about 70 day after calving while on 50% of first calf heifers have initiated estrous cycles at nearly 90 day after calving. Let's consider the impact of anestrus and calving date for a herd that calves from March 1 until May 10. Bull turnout is May 20 and the length of anestrus for mature cows is 60 days and for young cows is 90 days. A mature cow that calves on March 1 will begin to cycle on May 1 and is highly likely to conceive early. However, the mature cow that calves on April 20 won't cycle until June 20 and her opportunity to conceive early is very limited. A first-calf heifer that calves on April 20 won't begin to cycle until July 20 and will have limited opportunities to conceive. Cattlemen can reduce the anestrous period by fence-line exposure to a mature bull or by treating the cows with progesterone for 7 days prior to bull exposure. Sources of progesterone include the feed additive melengestrol acetate (MGA) or an EAZI-Breed CIDR insert (Zoetis Animal Health). Both sources have been shown to induce estrus in anestrous cows and exposure of anestrous cows to progesterone for 7 days before bull exposure will not reduce fertility. Pregnancy rates will actually be increased in these females because inducing estrus will increase the number of opportunities these cows have to conceive in the breeding season.

Managing for reproductive success actually begins at calving. Cows need to calve with a minimum BCS of 5 and with little assistance. Effective planning for reproductive health and management plan for limiting the impact of anestrus will ensure that cattlemen are happy, happy, happy at the end of the breeding season.

Weekly Mandatory Price Reporting - Matthew A. Diersen, Professor, Department of Economics, South Dakota State University

Back when there was a little more snow on the ground, I came across a notice that the Mandatory Price Reporting Act of 2010 has a sunset clause in it dated September 30, 2015. That inspired me to reexamine the content of the various reports for cattle, lest anything be taken for granted. The focus here is mainly on the weekly reports at the national level. Recall that mandatory reporting is covered by the USDA's Agricultural Marketing Service (AMS) and it pertains to animals marketed directly to larger packers. The reports referenced below are available at: http://www.ams.usda.gov.

Cattle that have been set for marketing are documented in the committed and delivered report (LM_CT142 or just 142), which provides a breakdown of volumes by pricing mechanism (negotiated, negotiated grid, formula and forward contract), weight determination (live or dressed) and pen make-up (e.g., steers, heifers or mixed). From there, the reports tend to capture behavior at the time of purchase or of slaughter. For example, a feedlot may forward contract months in advance of the animal being ready for market (purchase point). After the animal is delivered to a plant the final characteristics and value are fully known (slaughter point). The negotiated purchases report (154) is a weekly summary of the cattle bought the prior week. Most the volume in this report is for negotiated cash purchases, providing prices most closely related to auction prices. Also included are negotiated grids, where only the base level is given. The final grid price is determined after slaughter and given in the formula and forward report (151) with final formula and forward prices. The various net prices across mechanisms show the variability from realized versus expected quality.

Missing from the price summaries are the packer owned cattle (153). Carcass characteristics and volume can be monitored to see if packers own cattle that differ from average cattle. That report also summarizes the forward contract volume and different basis metrics. Differences among the various prices can be partially explained by considering the premiums and discounts (155). A separate report, cows and bulls (168), is helpful for gaining regional insights into what is being sold. Only a couple reports are aggregated further, the monthly committed and delivered report (143) and the 5-Area series (annually in 170 and monthly in 180). Knowing the volume delivered on a monthly level seems to make more sense than on a weekly level, especially for regional breakdowns. The aggregations also distinguish between aberrations and trends.

Before mandatory reporting, there was looming concern that the shrinking percentage of spot market trades was leaving too much uncertainty in the market. Mandatory reporting gives clear insight into packer-owned and formula-purchased cattle that would be hard to replicate or imagine in a voluntary setting. The forward contract information is unique under mandatory reporting because it is comprehensive. Over time the various reports have added more distribution information to the series, which also relies on the comprehensive nature of mandatory reporting.


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BEEF Cattle is a weekly publication of Ohio State University Extension in Fairfield County and the OSU Beef Team. Contributors include members of the Beef Team and other beef cattle specialists and economists from across the U.S.

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