As pork producers strive to make rapid genetic improvements in their herds, we've seen a tremendous increase in the number of boar studs. Artificial insemination (AI), using top-indexing boars, is without a doubt the fastest and most efficient method of achieving genetic improvement within any swine herd.
However, the risk of disease spread through semen is a continual concern of pork producers. Although the risk may not be as high as that associated with the actual introduction of new breeding stock into your herd, the concern is valid, especially when dealing with diseases such as Porcine Reproductive and Respiratory Syndrome (PRRS). Call it the fear of the unknown if you will.
Disease risk management should always be addressed when making genetic selections. It is imperative to know your herd's disease profile before selecting a boar stud for your semen purchases. The stud should be disease compatible with your herd or, even better yet, at a higher health status.
The biosecurity measures required on boar studs are very similar to the isolation and acclimatization on commercial hog farms. In fact, the AI stud health monitoring requirements during isolation are usually more stringent because the AI stud contains boars from multiple sources. Export requirements of semen often require stricter protocols as well.
Isolation The biosecurity procedures for an AI stud start at the isolation facility where all incoming boars must go before entering the stud. The main reason for isolation is to prevent the possible spread of diseases by the incoming boars. The isolation facility is used for disease monitoring as well as acclimation to organisms from the AI stud. The isolation facility should be located far enough away (two miles minimum) to minimize the risk of disease spread to the stud. In order to achieve all-in, all-out (AI/AO) animal flows in isolation facilities, many companies are forced to operate multiple isolation facilities.
Control of people traffic to and from the isolation facility is very important. Personnel caring for the boars should be knowledgeable in all areas of swine management, including sanitation, nutrition, environment and detecting clinical signs of disease. Above all, the personnel must fully understand the impact of a breach in biosecurity protocols at this level. It only takes one mistake to result in a potential financial disaster to an AI stud. Therefore, the animals in the isolation facility should be the only hog the caretaker comes in contact with.
All equipment and supplies should be separate from the AI stud as well. If certain equipment is shared, it should be cleaned and disinfected after the isolation facility is emptied and before returning it to the AI stud.
The length of the isolation period is often dependent upon the diseases being monitored and the time period required to cease shedding of these organisms. The diseases monitored would depend upon several factors, including the prepurchase disease profile of the source herd as well as the ongoing disease profile of the AI stud. Certainly pseudorabies, brucellosis, PRRS, swine influenza virus and leptospirosis would be among the major health concerns monitored clinically and serologically.
Case Study No. 1 This case study involves a swine production system that services several farms with semen from two AI studs. One stud was PRRS positive while the other was populated with PRRS-negative boars.
Each stud housed approximately 100 boars. In the spring of 1998, the PRRS-negative stud broke with PRRS. After an extensive investigation, it was discovered that the cull truck protocol had been violated. The driver had gone to the PRRS-positive location first for pick up of culls.
Upon arrival at the PRRS-negative stud, the driver proceeded to enter the cull boar area and load out the boars by himself. The PRRS-negative stud broke with PRRS shortly after that. It was depopulated and repopulated with PRRS-negative boars at a considerable expense.
Biosecurity The biosecurity protocols on the daily operations within the AI stud are very crucial. The protocols must be written and strictly adhered to by all personnel. The protocols address concerns involving sanitation, people flows, animal flows, delivery of supplies, collecting, handling, and shipping of semen, culling procedures, as well as separate ventilation systems for each working area. The amount of detail that goes into developing these protocols is immense.
Health monitoring in the AI stud is an ongoing responsibility of the attending veterinarian. Frequent visits are required not only from a health monitoring standpoint, but from a regulatory standpoint because health certificates are required on semen shipped interstate and to other countries.
Accurate and complete medical records are a must for each boar in the stud; these records would start once the boar enters the prepurchase procedure.
Veterinarians are the key decision makers in the development of the disease risk management protocols. These protocols involve all facets of swine production and are crucial to the financial success of our client's business entity.