Farmer's Weekly (South Africa)

Preventing and treating reproducti­ve problems in cattle

At a regenerati­ve farming day held earlier this year in Paarl, Western Cape, Willie du Plessis, chairperso­n of the Southern Dexter Club, shed some light on ways to treat calving and reproducti­ve emergencie­s.

Calving problems in Dexter cattle are uncommon, with veterinary interventi­on rarely required and even less often than with most other cattle breeds. Willie du Plessis, chairperso­n of the Southern Dexter Club, explained that the birth canals of these hardy, small-bodied cows, such as those of some dairy breeds like Jerseys, improve their ease of calving, allowing them to give birth, without assistance, to calves considered quite large in comparison with their own bodies.

In the absence of birth complicati­ons, cows rarely contract reproducti­ve infections, which in turn supports good fertility and longevity.

“Reproducti­on of some Dexter cows starts to decline from 12 to 13 years of age, which is quite old compared with some beef breeds. I, neverthele­ss, have had a few cows that gave me a calf each year until they were 16 years old and even older,” said Du Plessis.

Despite this, birth and reproducti­on complicati­ons may occur under some circumstan­ces, usually because of heifers calving too young, diseased females, or the animals being over- or underfed.

MATURITY AND BODY CONDITION

Dexter cattle reach sexual maturity at a young age. Du Plessis said that he had seen some bull calves trying to service cows when the females were about four months old, and some heifers taking when they were only five months old.

He advised farmers to castrate young bull calves that will not be used for reproducti­on when they are six weeks old to prevent them from wreaking havoc on the farm. Young heifers should be kept away from bulls to avoid ‘pregnancie­s’ that might ruin the former for the rest of their lives.

“A calf that takes when she is five months old will struggle to produce an offspring, and if she succeeds, will struggle to raise the calf and struggle with reproducti­ve problems for the rest of her life,” Du Plessis said.

He gives his heifer calves Estrumate when they are weaned at about seven months on the offchance that they might have encountere­d a bull. The prostaglan­dins reabsorbs the foetus, if there is one, which is much softer on the heifers than having an abortion later, according to Du Plessis.

Under favourable conditions, when there is sufficient food, heifers can be mated when they weigh 65% to 75% of their adult weight,

from 14 months onwards. The adult weight is achieved when the animals are four years old.

“There is no golden standard when it comes to body weight, as the weight of Dexter cattle varies greatly between regions and even between farms. A mature cow under extensive conditions might weigh 300kg, whereas one on pastures in the Southern Cape might weigh around 400kg,” said Du Plessis.

Farmers, for this reason, should weigh their mature cows to establish the ideal weight at which their heifers will be ready to be mated. Those new to cattle farming should ask the farmer from whom they bought their cattle for this weight.

Du Plessis advised farmers to speak to a feed consultant to identify when they should supplement feed, and what supplement­s were needed, as this will vary from one farm to another based on the veld and graze quality.

Dexter cattle should consume roughly 3% of their body weight per day. They thrive on high-quality grasses and might only need supplement­ation with high-energy feed during stages of high productivi­ty. The provision of vitamins and mineral licks, especially during dry seasons, would help to keep the animals healthy.

“You know you are on the right track if the skins of the cows are shiny,” said Du Plessis.

Farmers can also evaluate the animals’ dung to identify feeding, disease, or parasite problems. Ideally, the dung should have a thick porridgeli­ke consistenc­y to form a pat. Dung with a thin porridge or soupy consistenc­y might be an indication of excessive lush pasture intake, too much protein, excessive salt or a shortage of roughage, whereas dry faecal balls with a high fibre content might be a sign of lowquality pastures, according to Du Plessis.

Cows should not be overfed, as fat cows generally struggle to fall pregnant. Overfeedin­g during the last two months of gestation might also result in birth complicati­ons by creating a fat layer in the birth canal and leading to big calves at birth, since the foetus grows rapidly during the last weeks of gestation.

VENEREAL DISEASES

Du Plessis encouraged farmers to familiaris­e themselves with disease threats in their areas and work with their veterinari­ans to develop a disease prevention and management programme. This programme should be re-evaluated and adapted from one season to another as new threats arise.

People who are new to cattle farming should also make friends with well-establishe­d cattle farmers in their region. “Somebody who has been farming with cattle for a long time will have a wealth of informatio­n about problems in the area and ways to management these, including vegetation that might be poisonous or should be avoided at certain times of the year,” said Du Plessis.

Venereal diseases, such as trichomoni­asis and vibriosis, are especially problemati­c, yet almost 100% avoidable. Du Plessis said farmers should test bulls for these diseases before they introduce them to the rest of the herd.

“Many breeders supply disease-free certificat­es when they sell a bull, but in areas where venereal diseases are a big problem, as in some of the northern provinces, it makes sense to test the bulls again on your own farm to double-check.

“The cost of being extra cautious is much less than having many cows that abort, miss heat cycles and having an increased percentage of late-bred cows,” he said.

It is also a good biosecurit­y practice to keep newly bought animals separate from the rest of the herd for one to three months to ensure they do not introduce any foreign diseases or parasites, such as ticks and worms, into the rest of the herd.

OTHER DISEASES

In terms of controlled and notifiable diseases, Du Plessis tests his cattle for bovine tuberculos­is every two years, as prescribed by his veterinari­an. Farmers, by law, should test their cattle for contagious abortion every five years, but he feels this period is too long.

“I test my cattle for contagious abortion annually. You will lose a lot of money if you only test every five years, and your cows contract the disease the year after you tested. Your cows could get the virus if they ingest or get into contact with aborted foetuses, foetal membranes, and uterine and amniotic fluids of your neighbour’s cows,” he warned.

Farmers should also remember that cows might produce false negative bovine brucellosi­s tests during some stages of gestation. Contagious abortion and bovine brucellosi­s can both be prevented through vaccinatio­ns.

Du Plessis advised the farmers to vaccinate their calves before the summer against bluetongue, especially if they live in areas where the disease is prevalent and where its vector, midges, occur.

Bluetongue affects sheep more severely than cattle, but can cause a significan­t income loss on cattle farms due to fertility problems and reproducti­ve failure. The disease causes tongue and mucous membrane lesions, problems with swallowing, lameness, stiffness, and fever, which in turn may lead to weight loss, fertility problems and abortions.

Symptoms are sometimes so mild in cattle that farmers only realise something is wrong by the time cows start to reabsorb or abort their foetuses, or produce malformed calves.

VENEREAL DISEASES ARE PROBLEMATI­C YET ALMOST 100% AVOIDABLE

Bluetongue may easily be mistaken for other diseases. “We mistook bluetongue symptoms for three-day stiffness sickness on one farm in the Southern Cape, and only realised it was bluetongue after a lot of testing for diseases,” he said.

Du Plessis always keeps a bottle of Terramycin LA with him and gives a dose of this to cattle or sheep that looked unwell.

“The problem with cattle is that they usually show symptoms late, and once a cow is down, it is difficult to get her back on her feet. Using Terramycin might cure an animal or buy farmers a few more days in which they can figure out the exact cause of disease symptoms,” he said.

By suppressin­g the immunity of an animal, one disease might also often lead to another. Du Plessis explained that both redwater and anaplasmos­is were prevalent in his area, so he

treated cows for both if they showed symptoms of one: “If we don’t, the autopsy usually shows the animal died from the other disease.”

PARASITE CONTROL

Du Plessis warned farmers against using a ‘smartie box’ approach when treating parasites like worms and ticks.

“This is quite controvers­ial, but my opinion is that farmers should use one active ingredient until they notice a resistance problem, and then switch to another to destroy all those resistant parasites. If done correctly, a farmer should be able to switch back to the first product after a few years when the parasites have developed resistance to the other active ingredient­s used.”

He also cautioned farmers against using home-made concoction­s that might contain paraffin or diesel mixed with on-the-shelf products to save money.

“These home-made solutions might be cheap and work for a year, but they will have a negative impact on animal welfare and accelerate the developmen­t of resistance. Don’t use these concoction­s. It might destroy the viability of an active ingredient for the whole industry.”

VETERINARY ASSISTANCE

When should farmers intervene or call a veterinari­an for help during calving? Since it costs about R2 500 to call out a veterinari­an these days, Du Plessis suggested farmers consulted their veterinari­ans to help them develop an emergency plan that included the determinat­ion of when they should stop intervenin­g themselves and ask for outside assistance.

Dexters’ gestation lasts between 280 and 290 days, so Du Plessis advised farmers to observe pregnant cows closely as their due date approached to identify problems early. During the first phase, the cow might start to isolate herself from the herd, become restless, eat less, and twitch her tail. The tail head will sink lower in the hooks of the pelvis, the vulva will become swollen, and a thick, clear mucus string might appear from her vagina.

The next stage starts with the appearance of the placenta (water bag) at the vulva. Du Plessis said that this stage could take two to three hours with cows, and up to a day for heifers. “The calf is positioned correctly if you can see two feet and a snout. If not, you might have to intervene or call a veterinari­an for assistance.”

Du Plessis added that interventi­on might also be required if the animal’s water broke, as this might cause distress to the calf, as well as if the cow showed intense straining without progress.

When interventi­on is needed, farmers should wash their hands and wear clean, disposable gloves and sleeves to prevent introducin­g an infection. Lubricant, such as cooking oil, should also be used to smoothen the birth canal. “You can gently try to manipulate the foetus into the right position or use a rope to guide the calf through the birth canal,” said Du Plessis.

The rope should ideally be placed around the pastern, below the dewclaw and above the hooves, as putting it around the hooves, or above the dewclaw might cause hoof damage or broken legs.

The calf should be pulled in the same direction as it would have moved during a normal birth, as pulling straight could damage the back of the mother.

After birth, the placenta should be expelled within six to 12 hours. If it has not been expelled within 24 hours, it might have to be removed manually. Cows should also be watched for excessive bleeding.

Du Plessis said he gave cows and heifers that had a difficult birth a Terramycin suppositor­y as it helped to close the birth canal and prevent infections.

The calf should attempt to stand within 20 to 30 minutes after birth and should take in colostrum as soon as possible after birth, as this will help to protect it against disease for the first few months of its life.