Effect of breed on response to foot rot treatment in mature sheep and lambs
Abstract Our objective was to determine whether breed differences existed in response to exposure and treatment of virulent foot rot. Dorset (DS), 1/2 Dorper (DX), 3/4 or greater Dorper (DO), Gulf Coast Native (GC), Katahdin (KA), and St. Croix (SC) mature sheep and lambs were exposed to virulent foot rot in spring 2003. Treatment for foot rot was initiated in 132 lambs and 262 mature sheep in late July. There were eight pasture groups treated, two of which were minimally exposed to foot rot. Treatment included hoof paring, foot bathing with 10% zinc sulfate with surfactant, allowing the zinc sulfate to dry on the foot and moving to a small paddock that had not been exposed to small ruminants for more than 14 d. Foot bathing was repeated every 7 d for a maximum of five treatments. Animals that had not responded (odor or any indication of persistent infection) by then were culled from the flock. As an indication of severity of foot rot for each animal, the number of areas on the foot (interdigital and two digits for each foot), a foot score (0 = no infection found; 1 = infection of digits only; 2 = infection of interdigital area and could include digits), and presence of characteristic odor was recorded. Least squares means for number of areas infected were greater for mature than growing sheep (2.07 ± 0.16 versus 0.88 ± 0.31; P P P P P P P P
Lameness in small ruminants
Olechnowicz J., Jaukowski J. M. Lameness in small ruminants Summary The main causes of lameness in sheep include foot rot (FR), interdigital dermatitis (ID), and contagious ovine digital dermatitis (CODD). FR is a bacterial disease caused by Dichelobacter nodosus. An infection by faecal bacterium Fusobacterium necrophorum may develop as a result of injuries to the interdigital skin occurring over a prolonged period in a wet environment. FR is highly contagious and can be transmitted from sheep to sheep via pasture, bedding or handling pens; however, this disease can also be spread by sheep that do not show any clinical indications of the disease. In the case of ID infection, only the presence of Dichelobacter nodosus causes lameness. In most cases of CODD infection, Treponema vincentii has been isolated. The mean prevalence of lameness was around 8-10%, varied between years and depended on the climate and the standard of hygienic conditions. The main causes of lameness in goats were cracks and erosion on the horn of the bulbs of the heel that extended along the internal side of the axial hoof wall. Similarly as in sheep, Dichelobacter nodosus and Fusobacterium necrophorum were isolated from foot lesions. The clinical diagnosis was ID. The mean prevalence of lameness in goats ranged from 9% to 15%. The common detection of Fusobacterium necrophorum together with Dichelobacter nodosus supports the hypothesis that FR results from a synergistic interaction between these two organisms. Risk factors associated with infection and lameness in small ruminants are as follows: the wet season and moisture, smudge of dirt with mud of dens for animals, concentration of animals, virulence of the bacteria present, and the frequency of routine foot trimming. Particularly in sheep, an increased frequency of foot trimming is associated with an increased prevalence of FR. Lameness in small ruminants may also be related to an abnormal conformation of limbs or to lesions of the skin and udder. A highly reliable method for the evaluation of locomotion in small ruminants is the scoring scale using scores from 0 to 6. The treatment of infected animals consists primarily of their separation from the flock and the application of an antibacterial therapy, in which almost any topical antibiotic and foot spray can be effective. During transmission periods it is advisable to bathe animalsi feet in zinc sulphate (10 or 15%) or formalin (3%) every five days. Supplemental dietary biotin at 5.25 mg/day healed hoof lesions within 7 months. An improved locomotion of sheep was visible within 4 months. Vaccination plays a valuable role, but it is not fully effective, and immunity is of relatively short duration. Vaccination should be repeated at six-month intervals. Prevention and control of the two most common causes of lameness in small ruminants (foot rot and digital dermatitis) that eliminate Dichelobcter nodosus and Fusobacterium necrophorum are more feasible given the climate and environment can lead to minimization of lameness, improvement of animal welfare and increased productivity.
Effect of Soybean Cyst Nematode (Heterodera glycines) on Yield of Resistant and Susceptible Soybean Cultivars Grown in Ohio.
Soybean (Glycine max) producers in Ohio rarely use soybean cyst nematode (Heterodera glycines, SCN)-resistant cultivars because of concerns over limited yield potential and lack of resistance to Phytophthora sojae. A two-year study was initiated to determine grain yield and nematode population increase on soybean cyst nematode-resistant cultivars in maturity groups II and III in production fields. Sites differed in soil texture, nematode densities, and P. sojae infestation at a number of locations in Ohio. Soil was assayed for nematode densities before planting and at harvest. Yields of resistant cultivars averaged 0% to 18% higher than those of susceptible cultivars in fine-textured soils with average preplant populations ranging from 463 to 14,330 SCN eggs/100 cm(3) soil. In coarse-textured soils, yields of susceptible cultivars were 21% to 56% less than the resistant cultivars with average preplant densities ranging from 1,661 to 15,558 SCN eggs/100 cm(3) soil. The reproductive index ranged from 0.1 to 5.5 for resistant cultivars and 0.4 to 112 for susceptible cultivars. In 1993, yield of P. sojae-susceptible, nematode-resistant 'Asgrow A 3431' was as high as yield of the P. sojae-resistant, nematode-susceptible cultivar 'Resnik' in a Phytophthora-infested field. The nematode-resistant cultivars Madison Experimental 131527 and Asgrow A3431 had higher yields than AgVenture AV1341 and susceptible cultivars Resnik and Kenwood when compared over five nematode-infested sites. Nematode-resistant cultivars were found to be excellent alternatives to currently grown susceptible cultivars for managing SCN where group III cultivars are used. However, better cultivar alternatives may be needed for sites with combined Phytophthora root rot and cyst nematode problems.