Influence of Immunization Procedures on Upper Respiratory Tract Immunity in Cattle

Aspects of respiratory tract immunity have been investigated in the bovine species. Using Past. hemolytica type I as the antigen for this model the relationship of nasal and serum antibody production to the route of vaccination and type of vaccine was investigated in a series of 15 dairy calves from two to four months of age. Experimental results indicated that an aerosol vaccination with live Past. hemolytica resulted in a significant nasal antibody response while parenterally vaccinated gave calves with equivalent serum titers had no significant nasal antibody response.     

The implications of cognitive processes for animal welfare.

In general, codes that have been designed to safeguard the welfare of animals emphasize the importance of providing an environment that will ensure good health and a normal physiological and physical state, that is, they emphasize the animals' physical needs. If mental needs are mentioned, they are always relegated to secondary importance. The argument is put forward here that animal welfare is dependent solely on the cognitive needs of the animals concerned. In general, if these cognitive needs are met, they will protect the animals' physical needs. It is contended that in the few cases in which they do not safeguard the physical needs, it does not matter from a welfare point of view. The human example is given of being ill. It is argued that welfare is only adversely affected when a person feels ill, knows that he or she is ill, or even thinks that he or she is ill, all of which processes are cognitive ones. The implications for welfare of animals possessing certain cognitive abilities are discussed. For example, the extent to which animals are aware of their internal state while performing behavior known to be indicative of so-called states of suffering, such as fear, frustration, and pain, will determine how much they are actually suffering. With careful experimentation it may be possible to determine how negative they feel these states to be. Similarly, the extent to which animals think about items or events absent from their immediate environment will determine how frustrated they are in the absence of the real item or event but in the presence of the cognitive representation.     

Experimental crush of the equine recurrent laryngeal nerve: a study of normal and aberrant reinnervation

Experimental reinnervation of the equine larynx in healthy ponies was studied after the recurrent laryngeal nerve was crushed, using endoscopic, electromyographic, and microscopic techniques. In 12 ponies, the recurrent laryngeal nerve was crushed unilaterally in the midcervical area. All showed postoperative paralysis of the larynx on the operated side. In 8 ponies, recovery of movement of the vocal folds occurred at different times (2.5 to 8 months) after surgical operation was done. These movements, which were often abnormal, included trembling and asynchronism. In 2 of these ponies, complete return of normal vocal fold function occurred. Return of function was due to reinnervation, as determined by electromyographic examination of the laryngeal muscles and microscopic evaluation of these muscles and the recurrent laryngeal nerves. In the muscles, there was evidence of fiber-type grouping, and the nerves showed regenerative activity. In 3 ponies, there was evidence of aberrant reinnervation, with adductor or abductor muscles discharging during an inappropriate phase of the respiratory cycle. Further evidence that reinnervation occurred in the larynges of these ponies was determined in microscopic sections of the recurrent laryngeal nerves and muscles, which showed regenerative activity and muscle fiber-type grouping, respectively. The endoscopic abnormalities in these ponies were compared with those seen in horses with spontaneous subclinical laryngeal paralysis. However, the possibility that the abnormal endoscopic findings in this latter group of horses are due to aberrant reinnervation is thought to be unlikely.     

Further evidence that bovine IgM does not fix guinea pig complement

In a study of sera from cattle vaccinated with 3 X 10(10) cfu of Brucella abortus strain 19, it was found that IgG1 antibody measured by an indirect ELISA was the only isotype to correlate with standard complement fixing antibody titers using heated serum samples and guinea pig serum as a source of complement. A supplement of normal unheated bovine serum resulted in IgM fixing guinea pig complement, giving data similar to those obtained with unheated serum in the complement fixation test.     

Alterations in coagulation and hemograms of horses given endotoxins for 24 hours via hepatic portal infusions

This experiment was designed to establish a model for the study of gastrointestinal disturbances as a result of prolonged endotoxin uptake in the horse. The hepatic portal vein of 7 horses was catheterized (through flank incisions) to give chronic hepatic portal infusions of lipopolysaccharide (LPS, endotoxin). Lipopolysaccharide was infused at a rate of 1 microgram/kg of body weight/hr for 24 hours. Two of the horses were infused with saline solution for 12 hours before LPS infusions were given. Lipopolysaccharide was shown to affect behavior and hematologic and coagulation values. The 1st hour was critical for the LPS-infused horses; yet by 4 hours, the horses had apparently become refractory to continued infusion of LPS. During the 1st hour, all horses collapsed without an accompanying hypotension. A decrease in polymorphonuclear leukocytes (neutrophils) was seen during this time and was accompanied by a shortening of the recalcification tests, 1-stage prothrombin time, and activated partial thromboplastin time. There was an increased concentration of circulating fibrinogen/fibrin degradatory products. All of the LPS-infused horses showed signs of hoof discomfort and either stood with the 4 feet together beneath the body or continually shifted their weight from one front foot to the other. Hoof temperature decreased approximately 3 degrees (C) during this time and remained decreased for the duration of the experiment.