Despite dry pasture conditions across the United States, internal and external parasites will continue to challenge beef cattle operations heading into fall and winter. An effective parasite control program in the fall can help cattle maintain body condition and make the most of purchased feedstuffs.

Boehringer Ingelheim Vetmedica, Inc., Professional Service Veterinarians from three key beef cow-calf regions share the following insights with cattle producers as they head into the fall:

·      Diagnostics:Internal parasites are hard to diagnose without proper diagnostic tests. Work with your herd veterinarian to find out what species of parasites are challenging your herd. The main species to control varies from region to region in the fall of the year.

·      Different ages of cattle have different challenges:  Younger animals such as calves and replacement heifers are the most susceptible animals in the herd to internal parasites. By the time cattle have passed their second grazing season, they have developed a degree of ability to control Cooperia species on their own.  Cattle do not appear to develop resistance to abomasal parasites such as Ostertagia (brown stomach worm) and Haemonchus.

·       Read the label: The types of parasites controlled and for how long vary from product to product. Read the label to ensure you are controlling the parasites challenging your herd and that you are administering the proper dosage.

Fall parasite control challenges vary from region to region. Professional Services Veterinarians with Boehringer Ingelheim Vetmedica, Inc. offer the following insights for beef producers in three regions of the country.

Northern High Plains

Dr. Jerry Woodruff, Senior Professional Services Veterinarian with Boehringer Ingelheim Vetmedica, says that producers in the Northern High Plains states are most concerned with control of external parasites, such as lice, as they enter the fall months leading into cooler weather.

“Louse infestations are a significant concern for northern producers heading into late fall,” says Dr. Woodruff. “Another concern is the brown stomach worm, which goes into an arrested development stage within the animal as winter approaches. Producers should select a parasite control program that is effective against external parasites, as well as the inhibited form of Ostertagia.”

Despite the dry pasture conditions, Dr. Woodruff emphasizes that a parasite load can still be present and reinfestation is possible. The types of parasite challenges vary somewhat depending on the age of the animal. Young stock face challenges from Ostertagia ostertagi (brown stomach worm), Cooperia and Nematodirus, while more mature animals are likely challenged by brown stomach worm.

Dr. Woodruff recommends that producers use a pour-on in late fall for cows and replacement heifers to help with any external parasite challenges. Bulls that are being wintered over could benefit from a parasite control treatment for internal and external parasites in fall and a repeat application in late winter, just before spring breeding season.

Dr. Woodruff encourages producers to work with their herd veterinarian to determine the types of parasites challenging the herd and select products with proven persistence and efficacy.

Southeastern States

Producers in the southeastern United States face unique challenges in parasite control because cattle can graze nearly year-round, says Dr. Doug Ensley, Professional Services Veterinarian with Boehringer Ingelheim Vetmedica, Inc.

“A good deworming program in late fall helps cows maintain body condition heading into winter,” says Dr. Ensley. “This is important whether you have a spring calving herd or whether you have a fall-calving herd and you are setting them up for the next breeding season.”

Dr. Ensley says if hot weather persists into the late fall, producers need to be aware of challenges from Haemonchus and Cooperia in young cattle. As the weather cools and there is more moisture, then adult cows and bulls will have more challenges with Ostertagia coming out of the inhibited stage. In the Gulf Coast region, producers also need to have a plan to control liver flukes.

“Depending on the parasite species challenging your herd, you may select a different parasite control product for different age classes,” explains Dr. Ensley. “If inhibited Ostertagia is the challenge, then a pour-on product like Cydectin® (moxidectin) Pour-On makes sense. But in younger stock that is being challenged by Cooperia, Synanthic® (oxfendazole) Suspension is the better choice.”

Dr. Ensley reminds producers carefully read and follow all label directions.

One area that producers many times overlook is parasite control in their breeding bulls. If preparing for a fall breeding season, it is critical to control parasites so bulls can maintain body condition during a busy breeding season. Fall parasite control is also important for bulls wintering over for a spring breeding season.

“Body condition has an impact on semen quality,” says Dr. Ensley. “If a bull has a parasite load, it is difficult for him to maintain body condition even during the rest period. Semen is produced during the rest period, so we need to make sure bulls aren’t forgotten when it comes to fall parasite control.”

Dr. Ensley encourages producers to work with their herd veterinarian to develop a parasite control program based on the parasite species in the area.

Southern High Plains

Warm weather across the Southern High Plains allows for a longer transmission period for parasites, says Dr. Mac Devin, Senior Professional

Services Veterinarian. This longer transmission period can offer challenges for parasite control programs. Southern High Plains producers face challenges from Haemonchus and Cooperia in the early fall and greater concern from Ostertagia and lice as the weather cools down.

Dr. Devin encourages producers to work with their veterinarian to analyze the species before selecting a parasite control product. “With the higher cost of feedstuffs, it would be prudent to look at a science-based analysis to determine what parasite species are in the herd. That will help us choose the right product to get the best control,” says Dr. Devin.

 “If we know the parasite species, then we can select the right drug compounds for the best control,” says Dr. Devin. “Research has shown Cooperia with increased resistance to the avermectin compounds. If Cooperia is our predominant species, then we might want to look at the oxfendazole compound in SYNANTHIC for more effective control.”

Dr. Devin says that proper diagnostics will pay dividends for producers. “We have seen that there is a significant response to deworming in the face of a parasitism,” says Dr. Devin. “The key is to diagnose the type of parasite and the parasite load to develop the most effective course of treatment.”

To develop a more complete fall parasite control plan for your herd, contact your local veterinarian. For more information on the Boehringer Ingelheim Vetmedica, Inc., complete line of parasite control products, contact your local Boehringer Ingelheim Vetmedica cattle representative or visit www.bi-vetmedica.com.

CYDECTIN Residue Warning: When used according to label directions, neither a pre-slaughter drug withdrawal period nor a milk discard time is required. Meat and milk from cattle treated with CYDECTIN (moxidectin) Pour-On may be used for human consumption at any time following treatment. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal.

SYNANTHIC Residue Warning: Cattle must not be slaughtered until seven days after treatment. Because a withdrawal time in milk has not been established, do not use in female dairy cattle of breeding age. There are no contraindications for the use of SYNANTHIC bovine dewormer suspension in beef cattle.