Wear of permanent incisors with age on commercial Australian Angora goat farms

OBJECTIVE: To quantify if, and to what extent, permanent incisor wear differed with age of goat and farm of origin on commercial Australian Angora goat farms. DESIGN: Observations were made on three Angora goat farms in the wheat-sheep zone of Victoria, each managed according to the farmer's practices. Farmers provided a representative flock of does. METHODS: The proportion and pattern of wear of permanent incisors were recorded and percentage wear calculated. After log(y + 10) transformation, a parsimonious general linear model was developed to relate wear to farm and age, with age considered as a continuous variate. RESULTS: The range in wear of the permanent incisors was 0-100%. For each farm, the most parsimonious model for permanent first incisor wear and average wear of all permanent incisors was a separate straight line relating the transformed incisor wear to the age of doe. The models accounted for 66-73% of variance. On each farm the incisor wear was similar and low for ages up to approximately 4 years. On all farms, the amount of incisor wear increased dramatically with age, although the rate of increase differed with each farm. CONCLUSIONS: Permanent incisor wear increased with age of goat and differed with farm of origin. Angora goat farmers need to be aware of the potential for incisor wear to affect doe production and health.

Indices for the identification of biologically productive cashmere goats within farms

Objectively comparing cashmere goats with different cashmere production, mean fibre diameter (MFD) and staple length (SL) is difficult for farmers. We aimed to develop indices to enable cashmere producers to identify productive goats within their own farms once adjustments had been made for the primary determinants of cashmere production. That is we aimed to develop indices that identify goats and herds that biologically have a high fleece weight in relation to MFD and SL. We used a sample of 1244 commercial cashmere fleeces from goats originating from many Australian farms based in different environmental zones and a previously developed general linear model that related the logarithm of clean cashmere production (CCMwt) and any other potential determinant. In the present study, sub-models were investigated in order to develop new indices for comparing goats in the same farm, based on fleece characteristics and biological efficiency. New Index (MFD), equal to 6.02×CCMwt/1.1531^MFD, was developed to identify animals of biologically high CCMwt in relation to their MFD. Unlike previously reported results that MFD is not a useful measurement for comparing the biological efficiency of cashmere goats across farms, the New Index (MFD) allows comparison of the biological efficiency of cashmere goats within farms. New Index (SL), equal to 2.70 × CCMwt/1.1414^SL, was developed to identify animals of biologically high CCMwt in relation to their SL. New Index (SL) is very similar to the Clean Cashmere Staple Length Index (CCSLI) that had been previously reported for comparison of cashmere goats across farms, and thus the CCSLI can be usefully used for comparing the biological efficiency of cashmere goats both across and within farms. New Index MFD, SL = 8.90 × CCMwt/1.243^(MFD+SL)/2 was developed to identify animals of biologically high CCMwt in relation to both their MFD and SL within farms, and provides useful information above using either New Index (MFD) or CCSLI. The indices can be presented in the same measurement units as fleece weight, which is a biological concept easily understood by cashmere producers, and enable comparisons to be made between animals using just one attribute, clean cashmere weight.

Long-term epidemiological survey of Kudoa thyrsites (Myxozoa) in Atlantic salmon (Salmo salar L.) from commercial aquaculture farms

Kudoa thyrsites (Myxozoa) encysts within myocytes of a variety of fishes. While infected fish appear unharmed, parasite-derived enzymes degrade the flesh post-mortem. In regions of British Columbia (BC), Canada, up to 4-7% of fillets can be affected, thus having economic consequences and impacting the competitiveness of BC's farms. K. thyrsites was monitored in two farms having high (HP) or low (LP) historical infection prevalence. At each farm, 30 fish were sampled monthly for blood and muscle during the first year followed by nine samplings during year two. Prevalence and intensity were measured by PCR and histology of muscle samples. In parallel, fillet tests were used to quantify myoliquefaction. Infections were detected by PCR after 355 and 509 degree days at LP and HP farms, respectively. Prevalence reached 100% at the HP farm by 2265 degree days and declined during the second year, whereas it plateaued near 50% at the LP farm. Infection intensities decreased after 1 year at both farms. Blood was PCR-positive at both farms between 778 and 1113 degree days and again after 2000 degree days. This is the first monitoring project in a production environment and compares data between farms with different prevalence.