Perineal analgesic actions of epidural clonidine in cattle

Objective To determine the analgesic, sedative, motor, cardiac and respiratory effects of epidural clonidine in cattle. Study design Prospective randomized study. Animal population Six healthy male cattle weighing between 236 and 365 kg. Methods To investigate the effect of epidural clonidine, the animals received 2 and 3 µg kg^?1 of clonidine diluted to 8 mL with 0.9% saline. Two treatments were utilized as controls. The animals from the first control treatment received 2% lidocaine (0.4 mg kg^?1) and those from the second received an equal volume of 0.9% saline. Each animal received each treatment in random order. Evaluations of analgesia, sedation, muscle relaxation, heart rate, respiratory rate and rectal temperature were obtained at 0 (basal), 2, 5, 10, 15 and 30 minutes after epidural injection, and then at 30‐minute intervals until loss of analgesia occurred. All the animals received a standard noxious stimulus consisting of needle insertion into the skin and deep muscle; a 4‐point scale was used to score the response. A second scale was used to score sedation and a third for muscle relaxation. Results Both doses of clonidine were effective in producing analgesia of the tail, perineum, and upper hindlimb. Complete analgesia was present before (mean ± SE = 9 ± 4 vs. 19 ± 9 minutes) and lasted longer (311 ± 33 vs. 192 ± 27 minutes) for the 3 µg kg^?1versus the 2 µg kg^?1 dose, respectively. A dose‐dependent sedative effect of clonidine was also observed, with a peak effect between 60 and 180 minutes. No effects on heart or respiratory rates were observed with either dose of clonidine. Conclusions Epidural administration of 2 and 3 µg kg^?1 of clonidine in cattle in this study provided bilateral perineal analgesia/anesthesia with a dose‐dependent onset and duration of action. Clinical relevance Further studies are required to determine whether the analgesia is sufficient for surgery.     

Forage yield and crude protein of interseeded legume‐bermudagrass mixtures as affected by phosphorus fertilizer 1

Bermudagrass (Cynodon dactylon L.) is a warm season perennial that is well adapted in the southern Great Plains. It is one of the region's most important forage crops used for livestock production, and is commonly grown without legume interseeding. Recent research has investigated ways of improving the quality and quantity of this forage. The objectives of this study were to determine the effect of interseeded legumes and phosphorus (P) fertilizer on bermudagrass pasture forage yield and crude protein content. One experiment was initiated in 1993 in eastern Oklahoma in an established bermudagrass pasture. Red clover (Trifolium pratense L.), ladino clover (Trifolium repens L.), and two varieties of alfalfa (Medicago sativah), ’alfagraze’ and'common’, were interseeded by hand into an established stand of bermudagrass. The effect of P on forage yield and crude protein was evaluated using a 30‐kg P ha^‐1 rate applied at establishment versus no applied P. Forage yield was collected three times throughout the growing season each year from 1994 through 1997. When both alfalfa varieties were interseeded into a bermudagrass pasture without applying additional P fertilizer, forage yields for the legume‐grass mixtures decreased below those obtained from the monoculture bermudagrass in the first year of the stand. The alfalfa variety ‘alfagraze’ interseeded into established bermudagrass decreased total forage yield over the entire 4‐yr study. Interseeded red clover and ladino clover increased crude protein of the forage compared with monoculture bermudagrass the first two years of the study, with red clover continuing to increase crude protein in the fourth year. However, when 30 kg P ha^‐1 was applied to the bermudagrass prior to establishment of the legumes, no change in yield or protein was observed for both alfalfa varieties’ interseeding treatments versus the unfertilized mixtures. Although forage yield may not be increased, interseeding legumes into established bermudagrass could provide an efficient way to improve pasture crude protein without the use of inorganic fertilizers. However, if alfalfa ('common’ or ‘alfagraze') is interseeded, additional P may need to be applied at legume establishment to prevent possible yield decreases.     

3-methylindole induces transient olfactory mucosal injury in ponies

Response to 3-methylindole (3MI) varies among species. Mice recover from 3MI-induced bronchiolar epithelial injury but sustain persistent olfactory mucosal injury with scarring and epithelial metaplasia. In contrast, 3MI induces obliterative bronchiolitis in horses and ponies, but olfactory mucosal injury has not been reported. To evaluate the effect of 3MI on equine olfactory mucosa, ponies were dosed orally with 100 mg 3MI/kg (n = 9) or corn oil vehicle (n = 6). All ponies treated with 3MI developed obliterative bronchiolitis with mild olfactory injury. By 3 days after 3MI dosing, olfactory epithelium appeared disorganized with decreased and uneven surface height and scalloping of the basement membrane zone. Epithelial cells of Bowman's glands were hypertrophic. Proliferation of olfactory epithelium and Bowman's glands was supported by an increased mitotic index and positive immunohistochemical staining for proliferating cell nuclear antigen as compared with controls. The activity of 11beta-hydroxysteroid dehydrogenase, an olfactory mucosal cytosolic enzyme localized to sustentacular and Bowman's glandular epithelial cells, was concurrently decreased. By 9 days postdosing, olfactory mucosal lesions had lessened. Results indicate that 3MI transiently injures equine olfactory mucosa without the extensive necrosis, scarring, or metaplasia seen in murine olfactory mucosa or in equine bronchiolar epithelium.     

Use of remote sensing and geographical information systems to identify environmental features that influence the distribution of paramphistomosis in sheep from the southern Italian Apennines

A geographic information system (GIS) was constructed using remote sensing (RS) and landscape feature data together with Calicophoron daubneyi positive survey records from 197 georeferenced ovine farms with animals pasturing in a 3971 km(2) area of the southern Italian Apennines. The objective was to study the spatial distribution of this rumen fluke, identify environmental features that influence its distribution, and develop a preliminary risk assessment model. The GIS for the study area was constructed utilizing the following environmental variables: normalized difference vegetation index (NDVI), land cover, elevation, slope, aspect, and total length of rivers. These variables were then calculated for "buffer zones" consisting of the areas included in a circle of 3 km diameter centered on 197 farms. The environmental data obtained from GIS and RS and from data taken by the veterinarians on the field (stocking rate and presence of streams, springs and brooks on pasture) were analyzed by univariate (Spearman and ANOVA) and multivariate (discriminant) statistical analyses using the farm coprological status (positive/negative) as the dependent variable. Sheep on 32 of the 197 (16.2%) farms, were positive for C. daubneyi, with an average intensity of 52 epg. A multivariate stepwise discriminant analysis model was developed that included moors and heathland, sclerophyllous and coniferous forest vegetation, autumn-winter NDVI and presence of streams, springs and brooks on pasture. The variables entered in the model were also correlated with C. daubneyi positive farms in the univariate tests and are consistent with the environmental requirements of C. daubneyi and its snail intermediate host.     

The relationship between yield and assimilate supply in lychee (Litchi chinensis Sonn.)

Summary

Experiments were conducted on lychee (Litchi chinensis Sonn.) in subtropical Australia (lat. 27° –29°S) to evaluate the role of assimilates on fruit retention. All the leaves of the last flush, all the leaves of the previous flush (about eight leaves per terminal shoot), or all the old leaves were removed from trees. Medium (3–5.cm diameter) or large branches (5–10.cm diameter) were girdled and defoliated after fruit set, and fruit retention compared with ungirdled and undefoliated branches. Other branches were girdled and defoliated between anthesis and fruit harvest. Finally, 20, 50 or 80% of the flowering panicles were defruited on large trees. Defoliated trees had 35 to 45% lower yields than the controls. This was despite the treatment with all the old leaves removed having a much lower leaf area index than the other defoliation treatments (1.7 vs. 2.3 and 2.8). Leaves next to the inflorescences are more important for yield than the older leaves. Fruit retention was very low on girdled branches that had been defoliated, especially when the leaves were removed in the first 20.d after anthesis. This suggests that the yields of girdled branches were determined by the availability of assimilates soon after fruit set. In contrast, the number of fruit retained on ungirdled branches was unrelated to the number of leaves, with defoliation having no effect on yield. Fruit on these branches were supported by resources from elsewhere in the tree. Thinned trees had similar yields to those of unthinned plots (65–82.kg tree^–1). Thinning apparently increased fruit retention in the remaining clusters, under a higher leaf:fruit ratio. There were large differences in the concentrations of starch in the tree, and seasonal changes, with starch declining from flowering to fruit harvest. In contrast, there were only small responses to the treatments, suggesting that the fruit were mainly dependent on current photosynthesis. Photosynthesis in the leaves behind the fruit clusters was more important than photosynthesis in the older shaded leaves.