Stopping the itch

Stopping the itch

26 March 2018

Lice are parasites commonly found on cattle. They are host-specific and complete their entire lifecycle on the animal. They are generally classified into two types: biting lice and sucking lice.

Sucking lice have mouths adapted to piercing the skin of cattle and sucking blood while biting lice ingest skin and hair detritus, blood and scabs1. The life cycle of the lice is brief. Adults live for about one month and lay a few hundred eggs which glue tightly to the host animal's hair. These eggs hatch within a few days, producing nymphs resembling small soft adult lice. There are three nymph stages and each lasts about a week before the nymphs finally moult to become adults.

The number of lice found on cattle follows a seasonal pattern with numbers building up over autumn and winter and peaking in late winter or early spring. With any group of cattle there are always some animals carrying heavier lice burdens than others, and it is generally accepted very large louse populations are indicative of stress or concurrent illness. The impact lice have on your animals is proportional to the size of the infestation. Light or moderate levels have little or no effect on cattle. But heavy infestations cause skin irritation which cattle try to alleviate by scratching and rubbing. The result is damage to hides and farm structures. Some reports have indicated large populations of sucking lice can cause anaemia and weight loss. Lice may also act as a mechanical vector (carrier) for some blood-borne diseases such as Theileria2. The identification of lice infestations can be challenging because they are difficult to detect with the naked eye. Use a magnifying glass to look for the presence of eggs adhered to the hair at the edge of bald areas and carefully examine the skin on parting of the hair to reveal the adults and nymphs.

The good news is lice are fairly easily killed by applying an organophosphate, synthetic pyrethroid or pour-on endectocide (e.g. Cydectin® Pour-On). For complete removal of all lice it is important you treat all cattle in the mob at the same time and avoid the introduction or contact of untreated cattle after treatment.

The advantages of using Cydectin Pour-On for the treatment of cattle are:

  • Kills both biting and sucking lice3.
  • Effective against both internal and external parasites of cattle in New Zealand.
  • Has NIL milk, meat and bobby calf withholding periods.
  • Has been shown to increase milk production by approximately four percent compared to untreated animals4.

Why pay for a separate lice treatment, when the production increases you could achieve from using Cydectin Pour-On will cover this cost for you? Speak to your local Farm Source TSR to find out more about Cydectin Pour-On.

1 Andrews, A. Blowey, R. Boyd, H. Eddy, R. Bovine Medicine. Blackwell scientific publication. 1992 (17), 250-251.
2 Hammer, J. Jenkins, C. Bogema, D. Emery, D. Mechanical transfer of Theileria orientalis: possible roles of biting arthropods, colostrum and husbandry practices in disease transmission. Parasites & Vectors (2016) 9:34.
3 B. Losson, B. Lonneux, J. Field efficacy of moxidectin 0.5% pour-on against Chorioptes boris, Damalinia boris, Linognathus vituli and Psoroptes ovis in naturally infected cattle. Veterinary Parasitology 63 (1996) 119-130.
4 Murphy, A. The effect of treatment with moxidectin, a long acting endectocide, on milk production in lactating dairy cows. Proceedings of the 20th world buiatrics congress. 1998 (1) 463-469.

For more information on Cydectin Pour-On, visit your local Fonterra Farm Source store today.

Article supplied by Zoetis