No abstract

This study was designed to identify changes in parasite-specific immune responses that occur during vertical transmission of Neospora caninum and can be used as indicators of parasite reactivation in naturally infected heifers. Ten heifers were unimmunized and 11 immunized with killed tachyzoites. One unimmunized heifer, which aborted at week 19 of gestation, had an increase in parasite-specific antibodies, mainly IgG(2), from week 15 to week 19 and a concomitant decline in parasite-specific cell-mediated immune (CMI) responses. Eight unimmunized heifers, which had live full-term congenitally infected calves, had an increase in antibodies, mainly IgG(2), from week 21 onwards. All immunized heifers delivered live full-term congenitally infected calves, and had a bimodal increase in antibodies; primarily IgG(1) following immunization and predominantly IgG(2) from week 17 onwards. Immunized heifers had significantly greater overall mean humoral and CMI responses than unimmunized heifers. Nine uninfected control heifers and their calves were seronegative. These results indicate that reactivation of a latent infection occurred in the naturally infected heifers, regardless of their immunization status, and was associated with increased parasite-specific antibodies, mainly IgG(2).

A major animal welfare issue facing the livestock industry is the care, handling, and transport of nonambulatory cattle. Consumers, researchers, practitioners, and animal protection organizations have questioned the quality of care provided to and management of nonambulatory cattle and raised questions about possible food safety concerns. Veterinarians and producers continue to be challenged with providing quality care for nonambulatory cattle. In addition, veterinarians are recognized as a credible source of information for consumers, regulators, and policy makers. Thus, it would be beneficial to provide peer-reviewed information to practitioners and others who must make clinical and policy decisions. Several sources a-f were searched by use of various key words to identify relevant peer-reviewed citations for the information reported here. In addition, governmental and lay reports were reviewed to ascertain policies, regulations, and historical data concerning nonambulatory cattle. Existing peer-reviewed information was considered adequate by the authors for the development of recommended on-farm management practices that could result in a decrease in the incidence of, an improvement in the prognosis for, and a benefit to the well-being of nonambulatory cattle. Definition of Nonambulatory or Downer Cows Wide variation exists in the case definition and related terms applied to nonambulatory cattle. The colloquial term downer has been used since the 1950s to describe cattle that are too injured, weak, or sick to stand and walk. 1 The term creeper has been used to describe cattle that are unable to use their hind limbs but that could propel themselves short distances with their forelimbs. 2 More recently, the term downer has commonly denoted cattle that are unable to stand after 24 hours of recumbency but that can maintain sternal recumbency. 3 Such cattle are sometimes referred to as alert downers to differentiate them from lethargic or moribund recumbent cattle that are unable to stand. The inclusion criteria A review of the causes, prevention, and welfare of nonambulatory cattle

No abstract

Humane euthanasia of cattle represents a challenge to the beef and dairy industries. Penetrating captive bolt, while traditionally considered to be only a stunning method, can be an effective single-step euthanasia method if both the cerebral cortex and brainstem are disrupted. This report describes a preliminary study investigating the likelihood of brainstem disruption for two captive-bolt shot locations. Heads were collected from 15 cattle that died or were euthanised for reason unrelated to the study and were then randomly assigned to one of two shot placement groups. Heads in the first group (n = 7) were shot at the intersection of two lines drawn from the medial canthus to the opposite horn or top of the opposite ear. Heads in the second group (n = 8) were shot at the intersection of two lines drawn for the lateral canthus to the opposite horn or top of the opposite ear. The guns were held perpendicular (as assessed visually) to the plane of the forehead. Shot placement was then assessed using computed tomography and disruption of the brainstem was determined. In the first group, the captive bolt failed to disrupt the brainstem in any of the heads. In the second group, the bolt disrupted the brainstem in 6 of 8 heads. The results suggest that selecting a higher shot location leads more readily to disruption of the brainstem which reduces the risk of regaining sensibility and should therefore improve animal welfare when cattle are euthanised with a penetrating captive bolt.