Milk replacer manufacturers can no longer produce products containing the familiar 2:1 ratio of Neomycin to Oxytetracycline. The old ratio of 2 parts Neomycin to 1 part Oxytetracycline has been replaced with a 1:1 combination of Neo-Oxy. This 1:1 antibiotic combination is restricted to either a very low level for improved feed efficiency and growth or a very high level for treatment of bacterial scours. The new low level can be fed continuously during the milk feeding stage, but the new high level has a feeding restriction of 7-14 days.
These changes make the manufacture of Neo-Oxy medicated milk replacers for treating scours much more limited, less practical and more expensive. Once supplies of milk replacer with the old 2:1 combination are gone, availability of milk replacers with Neo-Oxy will decrease substantially. In light of these changes, most milk replacer distributors and dealers are opting to forgo the use of Neo-Oxy in their milk replacers. Although some have chosen to take advantage of the low inclusion level, the commercial availability of milk replacers containing the treatment level of Neo-Oxy may all but disappear.
Upcoming deadlines (as outlined by FDA)
September 1, 2010: the last day manufacturers can ship finished product containing the old 2:1 combination.
October 2, 2010: all finished products with the old 2:1 Neo-Oxy combination must be cleared from distributor and dealer inventories and must be in the end-user's inventory.
Other sources of Neo-Oxy
All is not lost for Neo-Oxy users, however. Calf raisers will be able to purchase the 1:1 Neo-Oxy combination as a Type B medicated feed which can be added directly to non-medicated milk replacer on the farm to treat calves with scours. This Type B medication is to be added to milk replacer at the treatment level and is limited to a 7-14 day treatment period. Merrick's offers two Type B medicated feed products:
Super Guard -- regular formulation containing the maximum allowable dosage of Neo-Oxy
Super Guard Plus -- same formulation as Super Guard plus the added benefits of Direct Fed Microbials, Kaolin and high levels of vitamins A, D3 and E
Other milk replacer additives
What to do after Neo-Oxy can be a challenging decision. Many calf raisers will simply drop Neo-Oxy and feed a plain, non-medicated milk replacer. Many others will be looking to replace Neo-Oxy in some fashion. Although no other additive has the antibiotic action of Neo-Oxy, there are a number of options to choose from. Some calf raisers may choose another medication, such as Deccox or Bovatec, to provide protection against coccidia, while others may choose from a number of milk replacer additives that are currently available. These additives have different modes of actions, provide different effects, and can be added individually or along with medications.
Transitioning calves from Neo-Oxy milk replacer
Feeding milk replacer that is medicated with Neo-Oxy does have an affect on the population of organisms in the calf's digestive tract. Each antibiotic has a specific mode of action that undoubtedly puts pressures on certain types of organisms. If Neo-Oxy is suddenly removed, so is its influence. This can lead to rapid changes in the relative populations of organisms, and could result, for example, in an increase in organisms that cause scours or those that produce gas, leading to an increased incidence of bloat.
To reduce the likelihood of adverse effects when switching from Neo-Oxy milk replacer, the change should be made gradually -- this is true of any feed change. If possible, calves that have been receiving Neo-Oxy milk replacer should continue on that formula through weaning, with new calves being put directly on the milk replacer without Neo-Oxy. If that is not possible, the Neo-Oxy milk replacer should be blended (co-mingled) with the new milk replacer for a period of time to make the transition more gradual. Even though most calves and most farms should transition OK, a little planning ahead of time can make the change go more smoothly. For those calves that do have problems with the transition, it's important to consider treatment/management protocols ahead of time to help them through the challenges.
How important is Neo-Oxy in calf rearing?
As we move away from the use of Neo-Oxy in animal feeds, here are some interesting bits of research that may just make the transition a little easier.
- The first is from USDA, APHIS which reported in their 2007 National Animal Health Monitoring Service (NAHMS) study on the use of antibiotics on U.S. dairy operations. The study found that the use of medicated milk replacers has remained relatively constant, with 57.5% of operations feeding medicated milk replacer to calves in 2007, compared to 55.7% in 2002. They also reported that the use of Neo-Oxy in milk replacer increased from 25.6% of all operations in 2002 to 49.5% in 2007. That's interesting all by itself, but the real eye-opener is that they also found the percentage of antibiotic treatments of pre-weaned heifers for diarrhea and other digestive problems actually went up during the same time period for 13.1% in 2002 to 17.9% in 2007. In summary, the increased use of Neo-Oxy in milk replacer as a disease preventive does not appear to correlate with a reduction in the incidence or treatment of disease.
- The second research study is from Washington State and evaluated the effectiveness of antibiotic education on the use of antibiotics on Washington State dairy farms. Two surveys were administered, one in 2003 and one in 2005, with several educational interventions in between. About 247 dairy farms participated. After educational intervention, 51% of producers who originally reported using medicated milk replacer discontinued the practice, whereas 12% of producers began using medicated milk replacer between the 2003 and 2005 surveys. It appears a little education can go a long way toward changing management practices.
- The concern about antibiotic use and the emergence of bacterial resistance to antibiotic treatment has been a long-standing concern in both animal and human medicine. The third research example is a study of 60 Wisconsin dairy farms, one half using conventional production practices, the other half organic. This study was conducted to compare the susceptibility pattern of E. coli to antimicrobials in fecal samples collected from management systems with severely limited antimicrobial use (organic) to conventional production methods with less stringent restrictions on antimicrobial use. The results of this study indicate that E. coli isolates from conventional herds are more resistant to 7 of the 17 antimicrobials tested than isolates from organic farms. Furthermore, resistance is more common for isolates from calves than from adult dairy cows. Although this study was not specifically about Neo-Oxy and milk replacers, it does support the position that decreased antibiotic use reduces bacterial resistance to antimicrobials.
Transitioning away from the use of antibiotics in milk replacers may prove challenging for some, but by-and-large the transition should not be too difficult. Calf raisers may also find that using other milk replacer additives and medications results in overall improvement in calf health and performance.