Rill erosion in contrasting landscapes

Abstract. The data from the national project to monitor water erosion has mostly been treated in an aggregate form, because in many of the monitored transects in any year too few fields were eroded for the data to be split into its component parts. However, in crop year 1983 erosion affected enough fields in two localities with contrasting soils for their data to be compared. Rainfall patterns in the two localities were similar. The transects covered a sandland area in Nottinghamshire and an area of clayland in and on the margins of Bedfordshire. Compared with the clayland, rilling of the sandland was widespread, related to the greater range of crops grown there, and more severe. On clayland, rills were mainly confined to valley floors, and slopes flanking these valleys generally had lower gradients than those on the sandland. On sandland, slopes were steeper in eroded fields drilled to winter cereals than they were in fields planted to potatoes or sugarbeet. Such field- based studies hint at the complex interactions of rain falling on a cropped field. Erosional thresholds are not static. The areas of fields affected by erosion and deposition were mostly very small. This helps us understand why the farmer often considers erosion unimportant.     

Intramuscular injection in the cat

The commonly adopted technique and site for intramuscular injection in the cat are described, and the often resulting inadequacy and risk are discussed. An alternative site and technique are suggested to ensure a more reliable effect when an intramuscular injection is indicated. Résumé. On décrit la technique et l'endroit communément adoptés pour injection intramusculaire chez le chat et on discute de l'imperfection et du risque qui résultent souvent. On suggère un endroit alternatif et technique pour s'assurer d'un effet certain quand une injection intramusculaire est indiquée. Zusammenfassung. Die gewǒhnlish angewendete Technik und Stelle fur intramuskulàre Injektionen in Katzen sind beschrieben und das oft folgende Versagen und Risiko wird diskut-iert. Eine andere Stelle und Technik sind vorgeschlagen, um einer zuverlǎssigeren Wirkung sicher zu sein wenn eine intramuskulàre Injektion erforderlich ist.     

Genetic relationships between feed efficiency in growing males and beef cow performance

Most studies on feed efficiency in beef cattle have focused on performance in young animals despite the contribution of the cow herd to overall profitability of beef production systems. The objective of this study was to quantify, using a large data set, the genetic covariances between feed efficiency in growing animals measured in a performance-test station, and beef cow performance including fertility, survival, calving traits, BW, maternal weaning weight, cow price, and cull cow carcass characteristics in commercial herds. Feed efficiency data were available on 2,605 purebred bulls from 1 test station. Records on cow performance were available on up to 94,936 crossbred beef cows. Genetic covariances were estimated using animal and animal-dam linear mixed models. Results showed that selection for feed efficiency, defined as feed conversion ratio (FCR) or residual BW gain (RG), improved maternal weaning weight as evidenced by the respective genetic correlations of -0.61 and 0.57. Despite residual feed intake (RFI) being phenotypically independent of BW, a negative genetic correlation existed between RFI and cow BW (-0.23; although the SE of 0.31 was large). None of the feed efficiency traits were correlated with fertility, calving difficulty, or perinatal mortality. However, genetic correlations estimated between age at first calving and FCR (-0.55 ± 0.14), Kleiber ratio (0.33 ± 0.15), RFI (-0.29 ± 0.14), residual BW gain (0.36 ± 0.15), and relative growth rate (0.37 ± 0.15) all suggest that selection for improved efficiency may delay the age at first calving, and we speculate, using information from other studies, that this may be due to a delay in the onset of puberty. Results from this study, based on the estimated genetic correlations, suggest that selection for improved feed efficiency will have no deleterious effect on cow performance traits with the exception of delaying the age at first calving.     

Genetic parameters for cattle price and body weight from routinely collected data at livestock auctions and commercial farms

Beef outputs from dairy farms make an important contribution to overall profitability in Irish dairy herds and are the sole source of revenue in many beef herds. The aim of this study was to estimate genetic parameters for animal BW and price across different stages of maturity. Data originated from 2 main sources: price and BW from livestock auctions and BW from on-farm weighings between 2000 and 2008. The data were divided into 4 distinct maturity categories: calves (n = 24,513), weanlings (n = 27,877), postweanlings (n = 23,279), and cows (n = 4,894). A univariate animal model used to estimate variance components was progressively built up to include a maternal genetic effect and a permanent environmental maternal effect. Bivariate analyses were used to estimate genetic covariances between BW and price per animal within and across maturity category. Direct heritability estimates for price per animal were 0.34 ± 0.03, 0.31 ± 0.05, 0.19 ± 0.04, and 0.10 ± 0.04 for calves, weanling, postweanlings, and cows, respectively. Direct heritability estimates for BW were 0.26 ± 0.03 for weanlings, 0.25 ± 0.04 for postweanlings, and 0.24 ± 0.06 for cows; no BW data were available on calves. Significant maternal genetic and maternal permanent environmental effects were observed for weanling BW only. The genetic correlation between price per animal and BW within each maturity group varied from 0.55 ± 0.06 (postweanling price and BW) to 0.91 ± 0.04 (cow price and BW). The availability of routinely collected data, along with the existence of ample genetic variation for animal BW and price per animal, facilitates their inclusion in Irish dairy and beef breeding objectives to better reflect the profitability of both enterprises.     

Association between bovine digital dermatitis treponemes and a range of 'non-healing' bovine hoof disorders

This study describes the association between bovine digital dermatitis (BDD) treponemes and three 'non-healing' bovine hoof horn lesions, namely, 'toe necrosis' (TN), 'non-healing white line disease' (nhWLD) and 'non-healing sole ulcer' (nhSU), which are disorders that involve penetration through the horn capsule to involve the corium. In this study, these non-healing disorders (n=44) were identified as foot lesions that exhibited a topical granular appearance, exuded a typical pungent smell, were severely painful to the animal involved, and typically originated from farms where BDD is endemic. Given the similarities between these 'non-healing' lesions and BDD, the authors subjected samples of diseased tissue to PCR assays to detect the presence of DNA of BDD treponemes. All the three characterised BDD treponeme groups were identified as present together in 84.2, 81.3 and 55.6 per cent of samples of TN (n=19), nhWLD (n=16) and nhSU (n=9), respectively. In contrast, healthy control horn samples from similar sites (n=16) were PCR-negative for the BDD treponemes. Hence, these non-healing hoof lesions were strongly associated with BDD treponemes. Samples from typical heel horn erosions (n=9) were also subjected to BDD treponeme PCR assays and no association could be identified between the BDD treponemes and this horn manifestation.