THE VFD (VETERINARY FEED DIRECTIVE)
The VFD is part of the U. S. Food and Drug Administration’s regulation of use of antibiotics in livestock. These regulations are designed to 1) promote prudent antibiotic use, 2) protect human health, and 3) restrain development of resistance in microbes to antibiotics. My colleague Dr. Ted McCollum, at Texas A&M AgriLife Extension Service in Amarillo, has recently summarized the provisions of the VFD http://amarillo.tamu.edu/files/2010/10/The-Veterinary-Feed-Directive-SEP-2015-V.2-rel.pdf. The VFD (which will go into effect October 1, 2015, and must be fully implemented by January 1, 2017) addresses the use of drugs in feeds for livestock. Current focus is on antimicrobials that are considered medically important, that is, have applications in human medicine.
Dr. McCollum notes important provisions of the VFD rule:
- ends the use of medically important antimicrobials to enhance livestock performance;
- transitions many of the antimicrobials in feed that are currently available “over-the-counter” (OTC) into the VFD drug category;
- places the use of VFD animal drugs in or on animal feed under professional supervision of a licensed veterinarian;
- requires producers to obtain written VFD orders from a licensed veterinarian to purchase and utilize VFD antimicrobials on or in feed.
To purchase and use VFD materials, producers must receive a signed and written (not oral) authorization (a VFD order) from a licensed veterinarian. To obtain a VFD order, there must be an established veterinary-client-patient relationship (VCPR). A VCPR requires that 1) the veterinarian assumes responsibility for medical judgments of livestock and the client agrees to follow their instructions, 2) the veterinarian has sufficient knowledge of an animal’s condition in order to properly diagnose medical status, and 3) the veterinarian is readily available for follow-up care. A valid VCPR can not be established solely by telephone or electronic means.
If additives and complete feeds contain VFD drugs it will be noted on product labels. Some materials used in feed that currently require or will require a VFD by 2017 include, but are not limited to, feed-grade tilmicosin, chlortetracycline, neomycin, oxytetracycline, virginiamycin, and tylosin. Several drugs currently widely used in feeds for growth promotion, increased efficiency, etc. (such as bambermycin, lasalocid, monensin, MGA, and ractopamine) are not medically important in humans and so will not require a VFD unless used in combination with a medically important drug. A list of medically important drugs is at http://www.fda.gov/downloads/AnimalVeterinary/GuidanceComplianceEnforcementforIndustry/UCM052519.pdf under Appendix A. An extensive list of antimicrobials is at http://www.fda.gov/AnimalVeterinary/SafetyHealth/AntimicrobialResistance/JudiciousUseofAntimicrobials/ucm390429.htm.
VFD deals only with antimicrobials in feeds, not with other methods of administration such as injections. If you don’t use antimicrobials in feed you will not be affected by VFD. As one of my associates says, perhaps the regulation should have been called the Veterinary Medicated Feed Directive. For official detailed producer requirements see http://www.fda.gov/animalveterinary/developmentapprovalprocess/ucm455413.htm.
EFFECT OF LONGEVITY ON COW HERDS
Longevity in the cow herd is increased by reducing the proportion of females culled. In addition, greater longevity means a lower proportion of heifers are retained so the herd consists of a higher proportion of mature cows, whose calves outweigh those produced by heifers. In this study, reducing heifer replacement rate from 18% to14% increased lifetime productivity per heifer calf retained by 24%.
The authors noted that “current approaches for genetic selection to increase lifetime productivity have resulted in limited progress, due in part to possible interactions between nutritional environment and higher genetic potential for growth and milk production”. So, “rearing and managing cows under nutritionally limited environments may lead to adaptations that result in relatively high reproductive success under lower input levels”. That is, heifers developed under conditions similar to the mature cow herd may be better suited later in life to those conditions; but slower development also may reduce reproductive success in herds calving first at two years of age. Beef cow-calf management often requires tradeoffs.
Even though genetic selection has been minimally effective, the genetic tool of heterosis through crossbreeding has been shown to improve cow herd lifetime productivity by about 25%, or higher under particularly adverse environmental conditions. The authors noted that “crossbreeding improves retention rate due to cumulative benefits that heterosis has on the many factors contributing to cow success”.
(J. Animal Sci. 93:4235, 2014 Beef Species Symposium, Am Soc. of Anim. Sci. Annual Meeting; USDA-ARS Miles City, MT and Univ. of Nebraska)
GLYCERIN, ANOTHER COPRODUCT FOR FINISHING CATTLE
Glycerin, a coproduct of biodiesel production, can be used in livestock feed. It has advantages in flowability at low temperatures and does not corrode equipment. Also, protein content is low, which can be beneficial in offsetting higher-protein corn coproducts that might be included in a ration. Some prior work feeding glycerin has shown either neutral or positive effects on performance and carcass merit. However, no research has been conducted feeding glycerin along with supplemental fat, which is often used in feedyard rations.
Steers initially averaging 838 lb were fed for 112 days; rations contained either 0%, 2.5%, 5.0%, or 10.0% glycerin, along with 3.0% yellow grease. ADG and feed conversion among the four groups did not differ statistically. The same was true for all carcass traits, except that fat thickness decreased and Yield Grade improved as level of glycerin increased. The authors concluded that finishing rations could effectively use glycerin up to 10% in combination with fat up to 3%.
(J. Animal Sci. 93:3698; W. Tex. A&M Univ., Texas A&M Univ., USDA-ARS Amarillo, TX, USDA-AMS Clay Center, NE)
EFFECT OF METHOD AND TIMING OF CASTRATION ON STOCKER CALVES
A total of 271 crossbred calves (184 bulls and 87 steers) initially averaging 462 lb was obtained from livestock auctions in three groups. For all groups, calves were assigned to treatments as follows:
- calves that arrived as steers;
- bulls castrated surgically at arrival;
- bulls castrated surgically 14 days after arrival;
- bulls castrated with a rubber band at arrival;
- bulls castrated with a rubber band 14 days after arrival.
ADG was calculated over either 43 days, 50 days, or 53 days, depending on the purchase group. Calves arriving as steers had significantly higher ADG. Bulls surgically castrated on arrival had higher ADG than other bull groups. Bulls surgically castrated 14 days after arrival and band-castrated on arrival had lowest ADG. Over the entire feeding periods, fewer steers required treatment with antibiotics; there was no difference among bull groups in antibiotic treatment. NOTE: In some cases (especially during periods of low availability), bulls weighing less than 500 lb may not be price discounted. This study indicates they should be discounted.
(Prof. Anim. Sci. 30:457, Univ. of Arkansas)
SELL CULL COWS AT WEANING OR LATER?
Across the entire U. S., the largest number of calves is spring born and fall weaned. At weaning, many cows are culled from the breeding herd due to reproductive failure, or health problems. This generally results in lowest prices for cull cows in the fall, which has prompted some interest in retaining cows culled in the fall and marketing during periods of higher prices in spring.
Data were collected over three years from a herd of commercial Angus cows. Cows were culled in October, when calves were weaned, and marketed the following March or April. Cows were maintained either 1) on stockpiled native grass with minimal hay and 25% CP cubes during icy periods or 2) in drylot on grass hay and 25% cubes. At weaning, cows averaged 5.5 Body Condition Score, ranging from 4 to 8, with 23% classified as Thin (<BCS 5), 58% Medium (BCS 5-6), and 19% Fat (BCS>6). Cows were weighed monthly after being culled. Monthly ADG declined from start to finish. Pasture cows gained slightly more than drylot. Fat cows on pasture actually lost weight in February as did Fat drylot cows in March. For both systems of management, Thin cows had highest ADG and Fat cows were lowest. Total feed cost was $68 for pasture management and $262 for drylot.
The authors suggested that, for producers considering retaining cull cows after weaning fat cows should be immediately marketed. If resources are available, any retained cows should be maintained on range/pasture management rather than in drylot until marketing in spring. If resources are limited, thin cows should receive priority for retention over those in medium condition.
(Jour. of Agric. and Appl. Econ. 46:139; Oklahoma St. Univ., Samuel Roberts Noble Foundation)
DO GROWTH IMPLANTS FOR CALVES STILL WORK WITH TODAY’S GENETICS ?
Growth implants for calves have been around for over 40 years. Research evaluating implants on calves (almost always showing positive effects) was mostly conducted over 30 years ago. Over the years, genetic selection has generally increased weight, milking potential, and muscling. Researchers wondered if response to growth implants was still the same from current cattle.
At 30 to 90 days of age, 152 male calves were castrated, branded, and vaccinated; one-half of each group was implanted and one-half not implanted. When weaned 134 days after working, implanted calves had gained 20 lb more. This is essentially the same average level of response obtained 30-40 years earlier. Implanting is still as effective with today’s genetics. However, industry-wide implementation of implanting suckling calves continues to be at a low rate.
(2015 So. Sec. Am. Soc. Anim. Sci. Meeting Abst. 50; Oklahoma St. Univ,. Merck Anim. Health)
EFFECT OF WEANING PERIOD ON CALF PERFORMANCE
A group of 433 Angus X Hereford calves was weaned at either 60, 45, 30, 15, or 0 days before transportation (at average age of 220 days) for four hours to a commercial auction, holding there for 14 hours, and then transportation for 1 hour to a feedyard. All calves weaned before transport were maintained in drylot on a ration of 16.9% CP (DM basis). Upon arrival at the feedyard, all calves were fed this same ration for a 60-day receiving period. After that period, heifers were removed for cowherd replacements and steers were finished. At day 120 of finishing, 12th-rib fat thickness was measured ultrasonically and steers were assigned to one of three groups based on projected time to reach 0.45-0.5 inch fat. The following results were obtained:
- during on-ranch weaning, sickness increased as length of weaning period increased;
- at transport, 0-day calves weighed less than groups that had been weaned;
- transport shrink and sickness on arrival at the feedyard was higher for 0-day calves;
- on arrival, 0-day calves weighed less and weaned calves increased in weight as length of weaning period increased;
- feedyard ADG and slaughter weight did not differ among groups;
- days on feed decreased as length of weaning period increased;
- increase in cow Body Condition Score (from 60 days before to 60 days after calf transport) was similar for 0-, 15-, and 30-day weaning groups but higher for 45-, and 60-day weaning groups
- overall pregnancy rate was lower for the 0-day group but did not differ among the 15- to 60-day groups.
The authors concluded that weaning before transportation improved subsequent health and performance but that, under conditions of their study, weaning for 30 days or longer did not result in greater improvement than weaning for 15 days. NOTE: This is contrary to most certified preconditioned programs which require at least 30 days and generally 45 days. And conditions of this study were not as stressful as are encountered in many situations. Regardless, some period of weaning before transportation improved health and performance. However, this study reported no economic data, which should be considered in choosing whether or not to precondition and, if so, for how long.
(Prof. Anim. Sci. 31:20; Kansas St. Univ., Univ. of Nebraska)
2015 USDA DIETARY GUIDELINES AND SUSTAINABILITY
Starting in 1980, The United States Department of Agriculture has published and periodically updated human dietary guidelines. Preparation has been in progress for an update for 2015. In the process of development, along with dietary considerations it had been planned to consider sustainability, defined by USDA in this context as “evaluating the environmental impact of a food source”. After receiving comments from various sources with differing backgrounds and interests, USDA has decided to delete any consideration of sustainability from the 2015 Dietary Guidelines.