Estimated reading time: 5 minutes
The conditions in which pigs are produced vary, ranging from state-of-the-art facilities to the most basic of housing. In any pig production system, however, first-rate management and hygiene practices remain paramount to ensure continued production and profitability. Where management is lacking, diseases can quickly gain the upper hand.
According to Dr Dorothea Mostert of CS Vet, a veterinary and management consulting service for piggeries, pigs reach their full productive and reproductive potential in an environment where disease is expertly controlled. She groups the most common illnesses into three categories, each of which is discussed here.
In terms of reproductive diseases, porcine parvovirus (PPV) and leptospirosis are two deadly diseases that must be controlled at all costs. Once infected with these pathogens, pigs can be subjected to decreased conception and birth rates, an increase in abortions and stillbirths, and an increase in the number of weak piglets post-birth.
These events, says Dr Mostert, have a negative effect on the viability of the entire pig herd. “Parvovirus is present in most pig herds and if pigs are not vaccinated to boost their immunity, it may lead to large-scale reproductive losses.”
Leptospirosis also has several strains, each with unique characteristics in terms of host, transmission and clinical symptoms. Rodents play a key role in the transmission of these organisms, and the control of rats and mice is therefore an integral part of the management of piggeries.
There are commercial vaccines available for these two conditions – they also contain antigens that protect pigs against erysipelas (Erysipelothrix rhusiopathiae). Sows should be vaccinated at least two weeks prior to breeding, and replacement sows should be vaccinated twice before they are first mated. Boars need to be vaccinated every six months.
Diarrhoea in piglets
The piglet receives no antibodies via the placenta during gestation. Newborn piglets depend on the sow’s colostrum for antibodies against on-farm diseases.
It is essential that newborn piglets receive enough colostrum within the first day, emphasises Dr Mostert. “Newborn piglets are particularly susceptible to diarrhoea and here the bacteria Escherichia coli and Clostridium perfringens play an active role. E. coli produces a watery, often yellow coloured diarrhoea, whereas C. perfringens causes a characteristic cherry-red diarrhoea. Both can lead to pre-weaning mortality.”
Surviving piglets normally have a lower weaning weight and their ability to adapt in the next production phase is poor. “When sows are vaccinating during late gestation, it boosts the level of antibodies in the colostrum, thus ensuring that the piglet is protected and can resist bacterial infections. Mated replacement sows must be vaccinated twice during late gestation to have sufficient antibodies in their colostrum.”
Ideal conditions for farrowing
In addition to vaccination, maintaining hygienic farrowing conditions are crucial. The environment must be as clean as possible, and good washing and disinfection procedures need to be in place between cycles to reduce the overall pathogen load. Sows and piglets require an environment in which temperatures are well-regulated and which is kept dry and clean, especially during the period shortly before and after farrowing.
Piglets with diarrhoea can be treated with a suitable antibiotic, as prescribed by a veterinarian. Supportive treatment that includes an electrolyte solution is also often prescribed. First-rate hygiene during an outbreak will help prevent disease transmission between litters.
Internal and external parasites
High parasite loads impair the production capacity of herds. Pig roundworm (Ascaris suum), or large roundworm, is an internal parasite commonly found in pigs. During its life cycle, the larva migrates through the lungs, leading to coughing and even pneumonia in pigs. From there, the larva spends time in the liver, where it leaves characteristic white lesions. In case of a very heavy load, these lesions can lead to chronic decreased liver function.
Dr Mostert says transmission typically occurs when parasite eggs are excreted in the host’s faeces and then ingested by other pigs. “This is where good pen hygiene and management will help control the parasite.”
The mite Sarcoptes scabiei var Suis, which causes sarcoptic mange, is the most common external parasite in pigs and is transmitted through contact with infected animals. Itching in pigs is a sign of infection. They tend to shake their heads and rub or scratch themselves against objects. Instead of feeding, pigs will waste time rubbing and scratching, leading to decreased production. Pigs can also injure themselves while scratching, increasing the risk of secondary skin infections.
Sarcoptic mange typically occurs on the skin behind the ears, around the throat and on the lower body.
Ivermectin is effective against both parasites, and in addition to the injectable formulas, there are products available on the market that can be mixed into pig feed. Pour-on remedies are also available for sarcoptic mange.
Dr Mostert advises that producers consult their local veterinarian before using any vaccinations or preventive medications. The product leaflet must also be read carefully for possible side effects and appropriate meat withdrawal periods. – Carin Venter. Stockfarm
For more information, send an email to Dr Dorothea Mostert at email@example.com or phone CS Vet on 012 460 9385.