One of the main components of any control or clean-up plan is a thorough and strict biosecurity procedure to con tain and prevent the spread of disease. Pseudorabies (PR) clean-up can be frustrating or unsuccessful if biosecurity issues are not addressed. First, we must consider that the primary source of PR virus is probably the pig itself, and is spread either by direct contact or aerosol. All pig movements must be done in a way that minimizes the chance of disease spread between ani mals. Spreading between animals occurs when pigs of dif ferent age groups have close contact. Cull sows should never be kept in the finishing barn. Pig movements should be planned as all-in/all-out when possible. The disease threat to younger animals of keeping tail enders around is usually greater than losses from moving them out promptly. Additional walls or partitions may be necessary to gain greater separation between groups of ani mals. Air supply needs to be sourced from the outside, not from another group of hogs. When tending pigs, work from the youngest to the oldest with frequent use of disinfecting foot pans, especially in the finishing barns. When they get dirty, foot pans quickly become ineffective at killing disease organisms, so replace the disinfectant solution often. It is recommended to change coveralls and/or boots between the breeding and grow/finish herds. Equipment that is needed in several places on the farm should not be shared. Separate snares, syringes, or hog On-Farm Biosecurity For Swine panels should be kept for each phase of the operation. If this is not possible, equipment should be thoroughly washed and disinfected between groups of animals to prevent disease transmission. Common disinfectants are: formaldehyde-based (DC+R®), phenol-based (One Stroke Environ®, Magna phen®, Biophene®, Tek-Trol®, others), quaternary ammoni ums (Roccal-D®, Zephiran®), tamed iodine (Betadine®, others), and lye. There are differences between disinfectants in toxicity, corrosiveness, and effectiveness in the presence of dirt and low temperatures. DC+R is not effective at temperatures below 60 degrees and can be dangerous to use if ventilation is inadequate. Lye and phenol-based disinfectants are corrosive and can be dangerous to use. However, they are broad-spectrum disin fectants and are also the most effective disinfectants in the presence of dirt or low temperatures. Quaternary ammoni ums are very effective as long as the surfaces to be disin fected are not dirty. Disinfectants are effective only if adequate time is allowed for contact of the disinfectant with the surface. Exposure to sunlight and drying are also effec tive disinfecting procedures. Rodents, dogs, and cats have been incriminated as sources of PR virus spread in a number of outbreaks. Ro dents, pets, and birds also can transmit many other costly diseases (See the table below). Therefore, excellent rodent and bird control is necessary on a continuous basis. Rodents are attracted to areas piled with rubbish, so keep areas (Turn to Page 47)
Significant historical Pennsylvania newspapers