July Deworming – An Annual Profit Opportunity

By: Gil Myers, PhD
“Farming is a gamble –science improves the odds” *

July deworming is a frequently overlooked opportunity to control nematode (worm) infections and increase calf weight gains. Many cow/calf producers deworm their cows in the spring. The addition of a July deworming of cows and calves has been shown to provide seasonal control of worm infections in late winter/early spring born calves. Calves gain more weight and are heavier at weaning as a result of improved worm control during summer grazing.

The economic benefit of at least 30 pounds more calf at weaning through seasonal control of worm infections can be achieved at a cost of about $ 7.85 per cow/calf pair for a July deworming. Using a conservative weaned calf value of $ 1.70 /lb this increased gain provides a $ 5 to $ 1 return – one of the best investments available to commercial cow/calf producers.1

Worm larvae survive on pasture over winter; as a result suckling calves become infected as soon as they begin to graze spring grass. By 3-4 months of age calves have acquired economic levels of worm infection that typically slow growth until calves are weaned and removed from pasture. These calves appear normal but worm infections are reducing live-weight gain by as much as ½ pound per day.

July deworming of cows and calves is listed in the 2018 University of Kentucky Beef IRM Calendar as a timely management practice for spring calving herds. The reason July deworming is so timely is that treatment of calves and cows provides a twofold benefit: 1) Worm egg shedding is dramatically reduced for several months thereby preventing contamination of the pasture with infective larvae and reducing future infections, 2) Worm infections are removed thereby boosting their appetites and calf growth.
Seasonal worm control in cattle can be compared to controlling thistles – if we prevent thistles from going to seed we prevent future thistle problems. For example 50 calves, IF NOT dewormed, can shed 3,000,000 or more worm eggs DAILY onto pasture in July.

Deworming options have increased recently. Medicated free choice minerals now provide a practical and increasingly popular means to deworm cow/calf herds without working the cattle.  Southern States, ADM, Vigortone and Merck Animal Health market Safe-Guard medicated free choice mineral products. Most recently, Cargill introduced NutreBeef® Safe-Guard Dewormer Mineral. All of these products are designed to be consumed over a short 3 to 6 day period. Following consumption of the medicated mineral producers resume their regular free choice mineral program. To insure cows and calves all have access to Safe-Guard medicated mineral it is recommended that the medicated free choice mineral be offered in 8-10 foot long poly troughs. Larger herds should provide several troughs. By 3-4 months of age beef calves routinely consume mineral because they are growing bone and tissue and can successfully be dewormed along with the cows. Producers working their herds in July have a variety of individually administered dewormers available to them.

In summary, July deworming of late winter/early spring born calves and their cows is a practical management practice that provides cow/calf producers the opportunity to profitably produce heavier calves.
Author: Gil Myers, PhD is a livestock parasitologist who has researched and published on the control and economics of cattle parasites. Dr Myers is an independent consultant who shares the insights he has learned from both scientific and practical cow/calf management experience. Because ECONOMICALLY IMPORTANT nematode infections are everywhere but are difficult to detect, he encourages producers to gain knowledge of these parasites and their control. He promotes parasite monitoring which allows producers to objectively evaluate their worm control programs. Dr Myers owns Myers Parasitology Services an independent parasite monitoring laboratory and can be reached at gmyersph@scrtc.com.
*Forage – Livestock Quotes and Comments, D.Ball, G.Lacefield et. al.
1G.H. Myers, Strategies to Control Internal Parasites in Cattle and Swine, J. Animal Science 66:1988.