No description available.

No description available.

No description available.

In relation to hill sheep, the perception is that they live to a high welfare standard with minimal labour input per ewe, and that there is little reason for concern.  This perception has however not been confirmed by science to date, chiefly due to a lack of research interest into the hill sheep sector.  Meanwhile, extensive sheep farming faces increasing economic pressures, with low returns and falling government subsidy that may compromise animal welfare.  Labour has been shown to be a key input factor for both productivity and welfare in extensive production systems. Despite this, little research has been done to try and optimise the labour input for productivity and welfare. This study is a first attempt to link labour input, productivity and welfare in extensive sheep systems through empirical observation and computer modelling.  The fieldwork was undertaken from 2007 to 2009 on three research farms and three commercial farms.  Labour use was analysed within a number of defined tasks.  Linear programming (LP) modelling was then used to explore eight different scenarios with regard to sheep welfare, labour and productivity, and the potential impacts of specific management changes. Data analysis and model results showed hill sheep live to a high welfare standard according to the low incidence of welfare problems with low risks to productivity, confirming public expectations.  Farmers, are however, aware their attention to an individual sheep’s welfare brings poor returns in terms of flock productivity.  With this in mind, there is some scope for welfare-beneficial or –neutral reductions in labour, particularly if within-farm movement, e.g. between grazing areas, can be reduced.  However, larger reductions of labour, even within legal guidelines, could seriously endanger the welfare of individual sheep, though without great risks to productivity at flock or farm level.  Thus considerable savings in labour might, in some circumstances, reduce costs and hence improve profitability.

No description available.

No description available.

Paratuberculosis is a chronic enteropathy of ruminants that presents as two distinct disease forms in sheep; paucibacillary (or tuberculoid) and multibacillary (or lepromatous) disease. The immunopathology of paucibacillary and multibacillary sheep paratuberculosis has been linked to inflammatory Th1/Th17 cell and Th2/macrophage responses respectively. IL23 and IL25 are key to the development of these responses by interaction with their complex receptors, IL23R/IL12RB1 and IL17RA/IL17RB. Furthermore, the polarization of T cells and the development of appropriate immune responses is controlled by the master regulator transcription factor; T-bet, GATA3, RORγt and RORα. In humans, variations in the structure, sequence and/or expression of the genes encoding these proteins have been implicated in the different pathological forms of tuberculosis and leprosy, and gastrointestinal inflammatory disorders such as Crohn’s disease. In the current study, sequencing has identified multiple transcript variants of sheep IL23R, IL12RB1 and IL17RB and a single IL17RA transcript. RT-qPCR assays were developed for the cytokine receptor variants identified in this study and known transcript variants of the transcription factor genes. Expression levels were compared in the ileo cecal lymph node of paucibacillary or multibacillary paratuberculosis diseased sheep. Of the cytokine receptors; the IL12RB1v3 variant, which lacks the receptor activation motif, was differentially expressed and was significantly increased in multibacillary disease; this may contribute to high Th2 responses. Full length IL17RB was differentially expressed and was significantly increased in multibacillary pathology, which may also contribute to Th2 polarization. IL17RA was significantly increased in paucibacillary disease. The contrast between the IL17RA and IL17RB results may indicate that, in addition to Th1 cells, Th17 T cells are also involved in paucibacillary pathology. Of the transcription factor transcripts; full length TBX21 (T-bet) was differentially expressed and was significantly increased in paucibacillary disease; this may explain increased Th1 responses in these sheep. Full length GATA3 was significantly increased in paucibacillary compared to multibacillary sheep, suggesting a loss of Th2 responses in late-stage multibacillary pathology. RORAv1 variant was differentially expressed and was significantly increased in paucibacillary pathology, indicating a role of Th17 T cells in paucibacillary pathology.

Digitized by Kansas Correctional Industries

No description available.

Renal blood flow and micropuncture studies were conducted in late gestation fetal sheep (gestational age 134 - 141 days; term 150 days) and neonatal lambs (8 - 18 days after birth) to study the forces involved in glomerular filtration (GFR) and characterize the tubuloglomerular feedback (TGF) system during development. These studies required the kidney to be immobilized so stable models in acutely prepared anaesthetized animals were developed. Fetuses were studied in a heated water bath exteriorized from the uterus but with an intact umbilical circulation. The lower GFR in fetuses than lambs was found to be due to both lower net filtration pressures (P<0.001) and a lower ultrafiltration coefficient (P<0.001). TGF was present at both ages, but in fetuses the sensitivity was higher (P<0.001) and reactivity was lower (P<0.001). The reduction in TGF sensitivity between fetal and neonatal life may facilitate the increase in renal blood flow and GFR which occurs at this time. In both fetuses and lambs the sensitivity of the TGF curve was reduced by volume expansion (P<0.001, P<0.05) and reactivity was reduced in lambs (P<0.001). Furosemide abolished TGF at both ages. In both fetuses and lambs, TGF reactivity was increased by inhibition of neuronal nitric oxide synthase (nNOS; P<0.01, P<0.001) and in lambs, TGF sensitivity was increased (P<0.01). This indicates that nitric oxide produced by the macula densa modulates TGF during development. In offspring destined to become hypertensive due to maternal dexamethasone treatment in early gestation TGF sensitivity tended to be enhanced in fetal life and was enhanced in lambs (P<0.01). Increased TGF sensitivity may contribute to the development of hypertension in this model of developmental programming. The effects of nNOS inhibition were attenuated in these animals, suggesting that they have low tonic production of nitric oxide by the macula densa. In fetuses whose mothers had been subtotally nephrectomized prior to mating to induce maternal mild renal impairment, GFR was increased (P<0.01) but net filtration pressure was reduced (P<0.001) so the ultrafiltration coefficient was increased (P<0.001). TGF sensitivity was normal and the effects of nNOS inhibition were similar to normal fetuses.