Introduction
Sheep feedlots represent a specialized and efficient system of raising weaner lambs for meat production in an intensive environment. Lambs are placed into feedlot pens, where they are fed a carefully formulated ration to optimize feedlot performance. Average daily gain, average daily feed intake, feed conversion ratio and carcass parameters should be measured.
Due to a rapidly growing global population, this agricultural practice has gained popularity as a result of an increased demand for lamb and mutton.
The adoption of sheep feedlots is not without its challenges. These animals are entering a high stress, pathogen-filled environment often directly after weaning. Striking a balance between efficient production and responsible farming, with focus on good animal welfare and husbandry, is crucial.
There are vital steps in the sheep feedlotting process that need to be considered.
Lamb selection
Lamb selection is extremely important when purchasing lambs for a feedlot. There are many factors needing careful consideration when selecting a lamb for the feedlot such as weaning weight, age, and breed. These factors need to be thoroughly thought out and planned. For example, light weight lambs are automatically higher risk and are more predisposed to respiratory problems after arrival at the feedlot compared to heavier lambs.
Lamb arrival and vaccination
The 3R system is a practice that should be upheld before processing occurs. The newly arrived lambs need to have one hours rest for every hour they spent truck prior to processing. They need to rehydrate themselves with fresh cool water and have access to good quality roughage to stimulate rumen function. Effective vaccination and immunisation remains a vital step after lambs arrive at the feedlot. Vaccination programmes need to be tailored to a specific farm depending on risks and challenges the lambs may face at that farm. However, essential antigens to include in a processing programme are Clostridium perfringens type A ( (Redgut), Clostridium perfringens type D (pulpy kidney) and Pasteurella multocida type A and D. Most of the commercially available vaccines for sheep are inactivated ones and boosting these vaccines between 14-21 days is essential.
Metaphylactic and Therapeutic use of antibiotics
Metaphylaxis can be defined as the timed administration of an antibiotic to a group of animals at processing prior to feedlot entry. Various antibiotics can be included into a processing programme depending on season and lamb risk (light weight, recently weaned lambs). Antibiotics can also be used for therapeutic purposes, to treat animals that may be suffering from secondary bacterial pneumonias or enteric bacterial infections. Antibiotics should be reserved for when their use is absolutely necessary. The correct antibiotic, given at the right time (early in the disease process) , at the correct dose, via the correct route is essential. Antibiotics can only be dispended under the guidance of a veterinarian and instructions given by the veterinarian with regards to the use of antibiotics should be strictly adhered to.
Internal parasite control
Internal parasites, such as wireworm, can often be the cause of high mortality rates in a sheep feedlot. Lambs often enter the feedlot environment with a high internal parasite infection. The correct use of effective dewormers at processing needs to be implemented. With this being said, the issue at hand is the onset of internal parasite resistance on the farm of origin. As opposed to the frequent use of dewormers to combat a high internal parasite load, animals resistant to internal parasites (those not requiring frequent deworming ) should be selected for breeding. Routine faecal egg counts should be performed and those animals with high faecal egg counts with an absence of clinical signs (anaemia, bottle jaw) should be selected for breeding due to their innate resistance to these parasites. Camp control and breaking the life cycle of the worms is also an extremely important step to include. Never deworm animals and move them to a clean camp. The only thing being achieved with this exercise is the infestation of a clean camp with worms that are resistant to the deworming active that has just been used. Holistic internal parasite control is key and should be implemented in farming practices as much as possible.
Biosecurity
Selection of good quality lambs, avoiding light weight recently weaned auction lambs and ideally keep newly introduced animals apart from the rest of the feedlot animals for a period of time. Limit personnel entering your premises, as they too can be vectors for disease transmission. Regular disinfection of vehicles and persons entering the premises should be a compulsory activity, not only in the middle of disease outbreaks!!
Always keep in mind, the process of confining lambs in feedlot pens is not a natural setting. Problems may potentially be picked up as a result of this intensive production system. However, with the right lambs, a comprehensive vaccination programme, good biosecurity and a good working relationship with your veterinarian, this process can be a successful and profitable one for the feedlot operator.