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Frequently Asked Questions

Here's a list of questions swine veterinarians have asked members of MERIAL® veterinary and technical staff. We've posted the questions and their answers on so we can share valuable information with more veterinary professionals via the net.

Q. Is IVOMEC® Premix for Swine as effective as IVOMEC 1% Injection for Swine?

A. Yes. IVOMEC Premix for Swine, used as indicated at 100 mcg/kg of ivermectin for seven consecutive days, is as efficacious as using IVOMEC Injection for Swine. The use of the feed formulation can save time and labor, especially in treating growing and finishing pigs.

Q. What benefits can be derived with proper control of mange infestation using Ivomec?

A. Using IVOMEC Brand products for swine to eliminate mange and lice can improve average daily gain, increase the number of pigs weaned, increase weaning weights, improve feed efficiency, decrease the number of non-productive sow days, and lessen damage to equipment and facilities. Eliminating mange and lice with IVOMEC also helps reduce the swine operator’s possible exposure to insecticide sprays.

Q. What role do veterinarians play in the IVOMEC for Swine Herd Mange/Lice Elimination (HM/LE) Program?

A. Swine veterinarians play a vital role in the success of HM/LE programs. They perform site evaluations to assess and evaluate herd management, pig/people flow patterns, and isolation procedures. Veterinarians educate and train management and production workers regarding administration and injection techniques, animal weight estimates, and issues related to disease transmission. Veterinarians also determine product need, set up the treatment schedule, and supervise and monitor the HM/LE process. Veterinarians then certify herds as mange- and lice-free, providing the HM/LE protocol was implemented correctly.

Q. Why does the IVOMEC for Swine HM/LE protocol specify two doses of IVOMEC to eliminate mange and lice?

A. Mange mite and lice life cycles are such that in order to be assured that complete elimination of these two parasites takes place, two doses of IVOMEC as outlined in the HM/LE protocol are necessary for certification. Following proper biosecurity measures, guidelines on treating incoming and replacement animals, and proper isolation procedures will maintain a mange and lice free environment.

Q. How soon should I see a return on investment after implementing the HM/LE program?

A. Many HM/LE producers and their veterinarians indicate that they recovered the financial cost of implementing HM/LE within the first year. 2 Participating producers have indicated that they recorded increases in feed efficiency, average daily gain, number of pigs per litter, and weaning weights, and lessened the number of days for their hogs to reach market weight.

Q. Is the IVOMEC for Swine HM/LE program for every swine producer?

A. The IVOMEC for Swine HM/LE Program is intended for use by swine producers who have the managerial expertise and commitment to implement and maintain the HM/LE program fully. Full implementation according to HM/LE specifications enables you to certify that your clients’ animals are lice- and mange-free.

Q. Do herds ever break with mange after an operation has implemented the IVOMEC for Swine HM/LE Program?

A. It is rare, but it has occurred. The primary reason for re-infestation is failure to treat and isolate herd replacements. In cases in which herds break back with mange after HM/LE has been implemented, Merial works with the herd veterinarian and the herd manager to try to ascertain how the reinfestation took place and correct any breakdowns in implementation or management of the program. Elements of the program that are reviewed include: the treatment and isolation of replacement animals, weight determination for accurate dosing, the “marking” or identification procedure used to ensure that no animals missed their treatments, and biosecurity procedures. As long as the HM/LE protocol is followed, herds should be able to maintain their mange and lice free status.

Q. Why does IVOMEC cost more than other swine dewormers on the market?

A. IVOMEC is an endectocide – it not only treats and controls internal parasites (worms) but also treats and controls external parasites, mange mites and lice. Formulation diversity lets you and your clients choose the IVOMEC Brand product that’s best in a given situation:
* IVOMEC 1% Injection for Swine dosed at 1 mL/33 kg bodyweight,
* labor saving IVOMEC Premix for Swine 0.06% that producers can top dress or mix in complete feed.

Q. Is there any parasite resistance to IVOMEC?

A. There have been no reports of any resistance of swine parasites to ivermectin. IVOMEC offers the same high level of efficacy as it did when introduced in 1986.

Q. Why should I treat replacement gilts coming out of finishing barns that should be "clean?"

Scientifically speaking, there is no need to treat gilts coming out of the “clean” finishing area. However, most diseases in the breeding herd do come from the finishing area. 3 Some producers have a more relaxed biosecurity policy in this area where there is usually more traffic from people and equipment. If an individual animal is missed or not injected properly, it usually occurs in the finishing area, where restraint is difficult and accurate dosing could be compromised. Swine veterinarians and consultants have agreed that treating replacement gilts coming out of the finishing area is inexpensive insurance relative to the possible risk of reinfestation and retreatment of the whole herd.