Semiquantitative multi‐analysis of plasma obtained from Romney lambs (Ovis aries) by inductively coupled plasma mass spectrometry,and the classification according to feed type

The establishment of a classification system for domestic animals on consumed feed stuff is thought to be important from both a hygiene and market point of view. We collected plasma samples of Romney lambs (Ovis aries) which were fed one of the following: a herb‐clover mix (n = 10) which included chicory, red clover, white clover and plantain; a plant‐grass mix (n = 10) which included plantain, ryegrass and white clover; or a grass mix (n = 10) which included ryegrass and white clover. A total of 20 elements in plasma samples obtained from the lambs were analyzed using inductively coupled plasma mass spectrometry. The data were then analyzed by principal component analysis. The lambs were divided into three groups on a score plot depending on the different feed conditions. Furthermore, discriminant analyses of the elements were examined, using linear discriminant analysis with forward stepwise regression. This discriminant function correctly classified the samples from each group. The accuracy of classification of each group, as shown by 10‐fold cross‐validation, proved the effectiveness of the established discriminant function. It is concluded that using linear discriminant analysis might be a useful tool for the validation of elements from plasma in lambs grown in different conditions.     

Comparison of localization of the neurokinin 1 receptor with AMPA-type glutamate receptors in the rat spinal cord

With the cloning of the alpha-amino-3-hydroxy-5-methyl-4-isaxole propionic acid (AMPA)-type receptor subunits, it is now possible to localize these receptor subunits in the spinal cord. Comparison of the neurokinin 1 receptor distribution with that of non-N-methyl-D-aspartate glutamate receptor subunits (GluR1-4), considered to be AMPA-type, was investigated in rat spinal cord by immunocytochemical methods. Different patterns of immunolabelling were observed with the antibodies to the GluR1, GluR2/3 and GluR4 subunits in the lumbar spinal cord. Immunolabelling with antibodies to both GluR1 and GluR2/3 revealed intensive staining in the dorsal horn, while staining for GluR2/3 and GluR4 was dense in the motor neurons of the ventral horn. These results suggest that in the rat spinal cord AMPA-type receptors vary their composition according to the region where they are expressed. Neurokinin-1-receptor-expressing neurons in the dorsal horn do not appear to express the GluR4 subunit, however, whether they express the GluR1, GluR2/3 receptors subunits could not be determined.     

Tumor necrosis factor activity in serum from neonatal foals with presumed septicemia.

A study was performed to determine prevalence of tumor necrosis factor (TNF) activity in serum of equine neonates with presumed sepsis and to determine correlation between serum TNF activity and severity and outcome of disease. Twenty foals less than 21 days old were considered suitable for inclusion in this study by satisfying clinical and laboratory criteria suggestive of septicemia. At admission, blood samples were collected from all foals for determination of serum TNF activity, then clinical course and outcome of disease were recorded. Thirty-one clinically normal foals less than 21 days old served as controls for serum TNF activity. Serum TNF activity was estimated by use of an in vitro cytotoxicity bioassay and WEHI 164 clone-13 murine fibrosarcoma cells. Of the 20 foals with presumed sepsis, 5 had high serum TNF activity. Mean heart rate (P less than 0.005), mucosal petechial hemorrhages (P = 0.06), and death rate (P = 0.06) were greater in the group of foals with high serum TNF activity. These foals also had a lower mean neutrophil count (P less than 0.001), greater band-to-segmented neutrophil ratio (P less than 0.0001), and more prevalent neutrophil toxic changes (P = 0.07) than did foals without serum TNF activity (P = 0.02). Joint swelling was more prevalent in foals without serum TNF activity. Results of the study indicate that serum TNF activity is correlated with clinical criteria of sepsis in equine neonates. An association was apparent between disease severity and serum TNF activity in this group of foals with presumed septicemia.     

Modelling spring and autumn calving systems in beef herds of the Salado region of Argentina

Spring calving is recommended for beef herds in the Salado region of Argentina, but autumn calving is an alternative being used by some farmers. This study explored the biological and economic feasibility of autumn calving in cow–calf systems and their long-term performance compared with spring calving. Reproduction and calf performance data were collected from an autumn calving herd (1999–2005) and from a spring calving herd (1966–1995) at the INTA-Balcarce Research Station (37°45′ S; 58°18′ W). Similar data were obtained from a commercial farm which practiced both autumn and spring calving (1998–2003). These data showed that autumn calving is feasible in the region, provided that cows calve with a high condition score. This is a major difference with spring calving, where cows can normally gain weight during breeding. A climatically driven computer model was used to compare, at farm level, the effect of calving season across a range of combinations of weaning dates and stocking rates. Spring calving systems had greater production potential (15–20%) and profitability (17–28%) at high stocking rates. However, at low to moderate stocking rates, calving season had little effect on expected production and risk efficiency. This suggests that autumn calving could be a suitable alternative for the Salado region of Argentina. To exploit its potential, however, calf weaning age should be greater than with spring calving.     

Light-microscopy evaluation of zonular fiber morphology in dogs with glaucoma: secondary to lens displacement

Lens displacement resulting in secondary glaucoma is common in terrier breeds. This study was carried out to evaluate whether light microscopy was useful in detecting abnormal patterns in zonular fiber protein. Eyes from 63 dogs with glaucoma secondary to lens displacement were evaluated for the presence of abnormal zonular fiber morphology using the following stains: hematoxylin and eosin, periodic acid Schiff (PAS), Masson's trichrome and Verhoeff's elastin stains. Two distinct forms of abnormal zonular fiber morphology were recognized and designated as zonular fiber dysplasia (ZFD) and zonular fiber collagenization (ZFC). ZFD protein morphology was characterized by being tightly adherent to the nonpigmented ciliary body epithelium, exhibiting a distinct lamellar and cross-hatched pattern and staining strongly positive with PAS and trichrome stains, and staining negative with elastin stains. ZFD was predominant in terrier breeds (18 of 29) and Shar-Pei dogs (4 of 29). ZFC abnormality was characterized by excessive zonular fiber that was not tightly adherent to the ciliary body epithelium and staining positive with PAS, trichrome (blue for collagen) and elastin stains. Only 7 of 19 dogs with ZFC changes were terrier breeds, and there was no pattern in the breeds affected. Fifteen of the 63 dogs used in the study had normal appearing zonular fibers. The staining pattern in these dogs matched normal controls by staining positive with PAS and Verhoeff's elastin stains and had only minimal positive staining with Masson's trichrome stain. Results suggest that light microscopy is useful in detecting breed-related changes in zonular fiber morphology in cases of glaucoma secondary to lens displacement. These changes may correlate with the presence of abnormal zonular fiber proteins and might be important in the pathogenesis of primary lens displacement in terrier and Shar-Pei dogs.     

Within-farm spread of classical swine fever virus--a blueprint for a stochastic simulation model

A stochastic simulation model to investigate the transmission of classical swine fever (CSF) virus within an infected farm is described. The model is structured according to the processes that occur within and between management groups (pig units or houses). It uses the individual pig as the unit of interest and estimates the number of animals in the states 'susceptible', 'infected', 'infectious', and 'removed' for each day of the disease incident. Probabilities are assigned to the transitions between states. The probability of a pig becoming infected is made dependent on the probability of contact between a susceptible and an infectious pig as well as the probability of transmission. The more pigs become infected in one unit, the more likely is subsequent spread to another management group on the farm. Ultimately, the probability that a shipment of pigs from the farm will include at least one infected pig can be estimated in order to identify high-risk movements during a CSF epidemic. The model results were compared with experimental data on CSF transmission within one pig unit (management group). It could be shown that the model was capable of reproducing the experimentally observed infection and mortality rates. To improve the input parameters and for further model validation, more experimental data and field data from CSF outbreaks are needed.     

A new approach to managing health in Swine operations

It is proposed that just as the stethoscope and thermometer are fundamental tools for individual medicine, production and health recording systems are fundamental tools for effective population medicine. Treatment and control of clinical diseases as the primary objective is no longer considered appropriate for livestock population. Disease in populations now describes a deviation between what is happening and what is expected to happen. This redefinition of disease implies that it is of multifactorial origin and thus a different problem solving approach must be implemented. Therefore, a swine enterprise must be considered as a system, a set of interdependent components continuously interacting to produce pork. As a system, it is characterized by certain properties: change, environment, counterintuitive behavior, drift to low performance, interdependency, and organization. A redefinition of diseases implies also that they are not only “treated” but managed. Management consists of planning, monitoring, evaluation, and analysis. For this process to be implemented successfully, a goal-directed recording system providing a farm-based infrastructure for problem solving is essential. Clinical problem solving (diagnosis) is thus based on epidemiological and demographic methods.     

A survey of beef cattle farmers in New Zealand, examining management practices of primiparous breeding heifers

AIM: To obtain an estimate of the incidence of assistance at calving in primiparous (first-calving) beef heifers and the prevalence of breeding heifers at 15 months of age in New Zealand in 2006, and to identify factors contributing to farmers' decisions regarding breeding strategies for heifers, using a survey of beef cattle farmers. METHODS: A questionnaire was sent to farmers listed in a Massey University database and to members of selected breed societies, as well as published in an industry newspaper; 331 valid responses were received. Information was gathered on the age and number of primiparous heifers, number of heifers assisted, and the importance of various reasons for and against breeding heifers at 15 months of age. Respondents were also required to outline the criteria used for selecting bulls to join with heifers, and the strategies used to manage dystocia in primiparous heifers. RESULTS: Sixty-five (95% CI=58-71)% of respondents had only 2-year-old primiparous heifers in 2006, whilst a further 11 (95% CI=8-16)% had both 2- and 3-year-old primiparous heifers. The mean reported incidence of assisted calving was 7.0 (95% CI=6.4-7.5)% for 2-year-old primiparous heifers and 1.7 (95% CI=1.2-2.2)% for 3-year-old primiparous heifers. The reported incidence of assistance at calving within individual herds ranged from 0 to 100% for 2-year-old heifers. Respondents with bull-breeding herds most commonly observed their primiparous 2-year-old heifers twice daily, whilst respondents with commercial herds most commonly observed them once daily during calving. The most important reason for breeding heifers at 15 months of age was increased profit, whereas the most important reason for not breeding them at that age was concern about rebreeding performance of 2-year-old heifers. Estimated breeding value (EBV) for birthweight was the factor considered most frequently when selecting bulls to join with maiden heifers; age of bull and body shape of bull were the next most frequently considered factors. Selection of an appropriate bull was the most common strategy used to manage dystocia in 2-year-old beef heifers. CONCLUSIONS: The majority of respondents calved their heifers at 2 years of age, and increased profit was the primary motivator. Concern about the rebreeding performance of 2-year-old heifers was the most important reason among the remainder of respondents for not breeding heifers at 15 months of age. Dystocia in 2-year-old heifers was not a problem or a minor problem in most herds, but there was much variation amongst herds.