Estimated reading time: 4 minutes
- Summer is around the corner and has its own unique challenges when it comes to cattle diseases, especially in the summer rainfall regions.
- If producers can effectively control these first-generation ticks to prevent a second and third generation from taking hold, the battle is halfway won.
- When it comes to ticks, the biggest concern in summer are multi-host ticks such as the brown-ear tick, the heartwater or bont tick, and the bont-legged tick. Adult ticks feed mainly during the summer and the females are big.
- Two basic factors must be present for liver fluke to become problematic, namely water that is warmer than 10°C and the freshwater snail that serves as intermediate host in the life cycle of a liver fluke.
- Redwater, gallsickness, lumpy skin disease, three-day stiffsickness and several other diseases are associated with wet weather and high temperatures.
Summer is around the corner and has its own unique challenges when it comes to cattle diseases, especially in the summer rainfall regions.
Cattle usually carry a few adult ticks during late winter and early spring. The one-host blue tick is among the first to be observed on the animals. If producers can effectively control these first-generation ticks to prevent a second and third generation from taking hold, the battle is halfway won and there should be no redwater and gallsickness outbreaks in late summer and autumn.
When it comes to ticks, the biggest concern in summer are multi-host ticks such as the brown-ear tick, the heartwater or bont tick, and the bont-legged tick. Adult ticks feed mainly during the summer and the females are big. They feed quickly and are usually fully engorged within a week, after which they fall off the host. Their large mouthparts cause considerable damage to skin, and cause wounds that create the ideal environment for blowfly maggot infestations.
Watch out for parasites
Two basic factors must be present for liver fluke to become problematic, namely water that is warmer than 10°C and the freshwater snail that serves as intermediate host in the life cycle of a liver fluke.
Cattle’s liver play host to several adult liver flukes at the start of summer. The most strategic time to treat adult liver flukes is therefore at the end of winter or early spring, before the first rains arrive. Treating animals during this period means that producers can prevent pastures from becoming infested with liver fluke eggs, thus breaking the cycle.
Cattle are most prone to infestation in late summer and autumn. During the intermediate stage of the liver fluke, the parasite burrows through the intestinal wall, then migrates into the abdominal cavity towards the liver where it proceeds to burrow through the liver wall.
The flukes will now eat their way through the liver for six to eight weeks, maturing as they feed on the liver tissue before moving to the bile ducts. This is the most damaging stage of liver fluke infestation and is precisely why flukicides must be applied in summer to control the immature stage of the parasite; if not, the liver will be eroded until there is no remedy.
Roundworms also need controlling, as they affect not only production but also reproduction. Heifers are now approximately 18 months old and included in the group destined to be mated for the first time. They need to be dewormed with an effective remedy.
Read more about successful dosing programmes for a healthy beef herd.
Early summer concerns
The beginning of summer is marked by dry and dusty conditions, and low vitamin A levels in animals. Conditions are therefore ideal for a high incidence of eye infections. Injectable vitamin A supplements should be considered and animals showing signs of eye infection can be injected with a long-acting oxytetracycline.
The transition from winter to spring and finally summer brings with it a rather big difference in night and day temperatures. Pneumonia may occur during this transition period characterised by dry and dusty environmental conditions. Animals with a purulent nasal discharge or that present with other signs such as laboured breathing, must be treated with a remedy preferably prescribed by a veterinarian.
Blowflies can become a headache for producers in summer, especially if they lay their eggs in wounds caused by ticks, among others. The eggs will hatch, and the maggots will burrow into the wounds.
A last thought
Summer is also known for tick- and insectborne diseases. Redwater, gallsickness, lumpy skin disease, three-day stiffsickness and several other diseases are associated with wet weather and high temperatures. Producers must therefore gain thorough knowledge of the clinical signs of these diseases, as well as the best preventive tactics and treatment options.
This article contains only a brief discussion of the more common diseases known to crop up in spring and summer. Talk to your veterinarian to put a preventive plan in place, and to draw up a plan of action to treat sick animals. – Dr Chris van Dijk, Bovine Herd Health Specialist
For more information, contact the author at dairyvetza@outlook.com.
