Swine Notes 13 Reproductive Diseases cont PDF 2024

Notes 13: Reproductive Diseases Cont. & Musculoskeletal Disorders Reproductive Diseases Cont. Urogential tract infections Vaginal discharge syndrome Erysipelas Differential diagnoses of reproductive disorders Musculoskeletal Disorders Osteochondrosis...

Notes 13: Reproductive Diseases Cont. & Musculoskeletal Disorders Reproductive Diseases Cont. Urogential tract infections Vaginal discharge syndrome Erysipelas Differential diagnoses of reproductive disorders Musculoskeletal Disorders Osteochondrosis Footrot Self-study Osteomalacia Biotin deficiency 1 VETM4460 Swine Notes Reproductive Diseases Urogenital Tract Infections Incidence Pyelonephritis is a most common causes of death in sows. Herd outbreaks of vaginal infections occur sporadically and can have a significant negative impact on reproductive performance. Etiology A wide assortment of bacteria have been isolated from cases of urogenital disease. Most of these organisms are associated with manure. Actinobaculum suis is possibly the most important of the pathogens causing urogenital disease. Actinobaculum suis is frequently isolated from the sheath of boars. Presumably venereal transmission and poor hygiene are important factors. Clinical Signs Losses can be subtle. The presence of blood or mucus in the discharge usually indicates cystitis or pyelonephritis. Discharge may pool in the vagina and be visible through a speculum. Control and Treatment Free access to water is important, particularly in the case of cystitis and nephritis. Restricted water intake leads to an increase in urinary tract problems. Flow rates of water nipples should be set at 1 litre per minute and should be periodically checked (plugging or damage to water nipples frequently occurs). Vaginal Discharge Syndrome Clinical Signs A herd may have a higher number of repeat breeders and/or a higher-than-average sow mortality. A creamy discharge may be observed behind sows about 15 - 25 days following breeding or later. Sows suffering from reproductive disease often exhibit a vaginal discharge that can be noted as being a distinctly different colour than normal vaginal mucus. Often producers will notice it to be yellow in colour, but appearance can vary. It is also commonly noted that the normal clear mucus may appear to have a reddish tint that may be blood from inside the reproductive tract. It is also not uncommon for vaginal discharge to have an offensive odour that may lead to its discovery. Some sows are incapable of conceiving or carrying fetuses to term due to persistent reproductive problems. These sows typically can be noted to exhibit a vaginal discharge. 2 VETM4460 Swine Notes Control and Treatment When a small number of individuals can be identified, these sows can be culled. In the case of a herd problem, feed medicated with 400 - 800 grams of tetracycline has been used to reduce the level of infection. Cleaning the environment, particularly the breeding area, is very important. Cull all sows with vaginal discharges and as clean gilts are being introduced, breed these females by artificial insemination (A.I.) (or new boars if hand mating) to reduce the possibility of venereal spread. Erysipelas (Erysipelothrix rhusiopathiae) Etiology Erysipelas of swine is caused by a Gram-positive bacteria, Erysipelothrix rhusiopathiae. The bacteria persist for long periods of time in carcasses and possibly the environment. The disease is very widespread. Spread is generally pig-to-pig, but also by contaminated water and feed. A wide variety of animals can carry the organism including fish and poultry. In humans, E. rhusiopathiae causes a localized infection called "erysipeloid". Pathogenesis Most pigs encounter E. rhusiopathiae in their environment and may harbour the organism in tonsil and lymph tissue. Occasionally, bacteremia occurs. The organism produces an enzyme "neuramidase" which may be responsible for causing vascular damage. Pigs with erysipelas suffer widespread vascular damage with thrombosis of capillaries. This is evident in the skin as raised diamond-shaped lesions occur. In chronic erysipelas, vasculitis causes fibrin to enter the joints. There also is a marked villous proliferation of the synovial membrane. Emboli of E. rhusiopathiae sometimes cause inflammation of blood vessels within heart valves, which eventually develop into nodular vegetative growths. Most pigs that are exposed do not show signs of disease; stress is believed to play a role in disease outbreaks. Clinical signs Erysipelas commonly occurs in young sows close to (or at) the time of farrowing. The other age group that may be affected is the grower-finisher pig. In some areas, a peracute form of the disease occurs which causes sudden death and may affect a large percentage of a group. This type of outbreak is rare in North America. Typically, erysipelas causes a sow to suddenly go off feed and develop a very high fever. Within a day or so after the initial signs of illness, raised diamond-shaped skin lesions may occur over the animal's back. These lesions can be felt before they are seen. The raised areas become a deep red and eventually the skin may become 3 VETM4460 Swine Notes necrotic and dark. Affected pigs remain alert but show obvious pain when forced to stand. Joints may be enlarged. Diagnosis Most cases are diagnosed on the basis of skin lesions and on response to penicillin treatment. However, other bacteria (for example, Actinobacillus suis) can cause similar clinical signs including skin lesions. Bacteria can be isolated during early stages of the disease to confirm a diagnosis. Signs of septicemia may be present at necropsy, enlarged lymph nodes, hemorrhage on the kidney, swollen liver, spleen, and congested lungs. In chronic cases, proliferative, villous synovitis in one or more swollen joints may be found. Increased synovial fluid, thickened joint capsule, and organized inflammatory exudate may also be present. Vegetative endocarditis, if present, usually affects the mitral valve. Severe acute outbreaks involving large numbers of grower-finisher pigs needs to be differentiated from Salmonellosis and Hog Cholera. Control Sick pigs respond well to penicillin if treated early. Tetracycline could be used in feed and water during outbreaks in a grower-finisher barn. Vaccination is done routinely on most farms for breeding stock. Gilts are typically vaccinated prior to breeding and sows at weaning. The erysipelas bacterin is usually given in combination with other agents such as Leptospira spp. and Porcine Parvovirus. If a herd has a clinical problem in the farrowing barn, the veterinarian may recommend the use of the erysipelas bacterin alone a few weeks prior to farrowing. Nursery pigs are vaccinated if a problem occurs in grower-finishers. Protection from vaccination is short-lived (2 - 3 months) and breaks in protection occur occasionally. 4 VETM4460 Swine Notes  Differential Diagnosis of Reproductive Problems Differential Diagnosis of Reproductive Problems Condition Irregular Reduced Mummies Stillbirth Vaginal Postnatal Abortion Return Litter Size Discharge Death Parvovirus ++ +++ +++ + - - - Leptospirosis + - + +++ +++ - - Pseudorabies + +++ +++ +++ ++ - +++ PRRS + +++ +++ ++ ++ - +++ Seasonal +++ - - + + - + Infertility Vaginal ++ - - - - +++ - Discharge Syndrome Legend: - not a common characteristic + sometimes occurs ++ occurs more frequently +++common characteristic Musculoskeletal Disorders Osterochondrosis (OCD) In young breeding-stock animals, osteochondrosis (OCD) is the most important musculoskeletal disease. OCD is characterized by changes in the ossification process, particularly in the medial femoral condyle of the knee, the distal growth plate of the ulna, and the 6th - 8th costochondral junctions. Lesions observed on articular surfaces of joints include corrugations and ulcerations of cartilage, separation of flaps of articular cartilage from underlying bone, and cartilaginous cysts. Physeal cartilage also may be affected, and fractures may occur between the diaphysis and epiphysis. Clinical signs include lameness often involving more than one leg or abnormal gait. The most important cause of clinical lameness and culling for lameness in young breeding-age swine is osteochondrosis (OCD). Microscopic lesions of OCD are present in most gilts at the time of selection. Mechanical stress from trucking, mixing, breeding, and housing on slippery floors is likely the key factor, which causes animals with OCD lesions to become lame. Providing a "hardening-off" period after selection will reduce the level of culling due to lameness. This process involves low-density housing of gilts on a manure-straw pack or dirt floor for a period of a month or so between the time of selection, the time of trucking, and breeding. Osteochondrosis (OCD) may progress to 5 VETM4460 Swine Notes arthrosis and deformation of affected bones. Genetic predisposition, rapid growth rate, and management/housing factors causing mechanical injury are important contributors to clinical expression of this widespread condition. Poorly designed or badly maintained floors can cause direct injury to sows' feet such as bruising and torn dewclaws. Footrot Sows kept on wet floors are prone to footrot. Often affected sows are kept in loose housing. The sows lining up for single space feeders may result in wet areas near the feeders. Infections that cause cellulitis at the coronary band are called "bush foot". Sows are put in a dry area, perhaps in a crate, given systemic antibiotics and the foot is treated with copper sulphate. Self-Study: Osteomalacia Downer sows at the time of weaning are seen intermittently. Typically, the sow collapses in the farrowing crate, as she is walked from the crate, during movement or transport from the farrowing facility, or when she is mixed with a group of sows in the breeding area. The cause of this severe lameness is multiple bone fractures due to osteomalacia/osteoporosis. Sows with skeletal injuries are in extreme discomfort, become inappetant, and need to be euthanized. Low calcium levels in the feed, coupled with large litters and high milk production are the most common factors associated with this problem. Biotin Deficiency Biotin deficiency has been suggested as a cause of sow lameness. Experimental deficiency of biotin produces the following clinical signs: I. Dermatitis II. Brown ocular exudate III. Skin ulcers IV. Transversely cracked hooves with coronary band and solar hemorrhages V. Lameness VI. Stomatitis VII. Diarrhea Most reported cases have been associated with feeds based on small grains such as barley, which have little biotin. If a herd is being fed a ration of corn and soybean meal that is supplemented with a vitamin-mineral pack that includes biotin, it is doubtful that biotin deficiency would be the cause of the lameness. The problem is far more likely to be environmentally induced. 6 VETM4460 Swine Notes