The vasculature of 22 small colons from dead adult ponies was perfused with latex or barium sulphate solution. The vascular anatomy was studied by use of dissection and alkali digestion of the latex specimens and microangiography of the barium sulphate-perfused specimens. The small colon is supplied by the caudal mesentric artery. The left colic artery arises from the caudal mesenteric artery, which then becomes the cranial rectal artery. Branches from the left colic and cranial rectal arteries form anastomosing arcades that become narrower distally along the length of the small colon. From these arcades arise terminal arteries, which enter the small colon wall and give rise to a subserosal, an intermuscular, and a large submucosal plexus, with frequent anastomoses between them. The venous drainage closely parallels the arterial supply, except near to its origin from the portal vein, when the left colic vein and caudal mesentric vein are separate from the corresponding arteries.

Serum complement activity and selected hematologic variables were evaluated in 5 newborn foals fed bovine colostrum (principal group) and 6 foals allowed to nurse their dam (control group). Also, bovine colostrum was evaluated for anti-equine antibodies. Precolostral serum hemolytic and conglutinating complement activities were low and increased similarly in foals of both groups to reach adult values between 1 and 3 weeks after birth. Bovine colostrum strongly agglutinated, but did not hemolyse principal foals' RBC and blood containing all known equine blood group alloantigens. Hemolysis was not detected after administration of bovine colostrum. Physiologic anemia developed in foals of principal and control groups during the first week of life. Erythrocyte osmotic fragility in foals of the principal group prior to and after the ingestion of colostrum remained unchanged. However, at 36 hours after birth, there was a significant decrease in erythrocyte osmotic fragility in foals fed homologous colostrum.

The effect of aspirin on bovine platelet function and thromboxane A2 (TXA2) production in stimulated platelets was evaluated. A single dose of aspirin (100 mg/kg of body weight) was administered orally to Holstein cows, and blood samples were obtained before and at regular intervals for 7 days after treatment. The production of TXA2 was assessed by measuring the stable metabolite thromboxane B2, using a specific radioimmunoassay. Within 4 hours of aspirin administration, the production of TXA2 was significantly (P less than 0.05) decreased, irrespective of whether collagen, adenosine diphosphate, or platelet activating factor was used to initiate platelet aggregation. Despite the inhibition of TXA2 release from the stimulated platelets, platelet function, assessed by initial rate of aggregate formation and extent of aggregation, was unaffected by aspirin administration. The extent of aggregate formation in response to collagen, adenosine diphosphate, or platelet activating factor was independent of the amount of TXA2 released from platelets before and after aspirin treatment. The results suggested that TXA2 formation is not the primary biochemical pathway involved in the aggregation of stimulated bovine platelets.

Immunodeficiency in neonatal and young pigs was studied in terms of T-cell function. Generalized T-cell deficiency did not exist in young pigs on the basis of the in vitro response of blood mononuclear cells to a polyclonal T-cell mitogen, phytohemmagglutinin. However, immunodeficiency that extended from birth up to 4 weeks, was observed in serum antibody concentration and in vitro proliferative responses of blood mononuclear cells from young pigs exposed to a low antigen dose of a T-cell dependent antigen, egg white lysozyme. The low in vitro proliferative response to lysozyme was not attributable simply to a lack of interleukin-2 production, because supplementation with human interleukin-2 did not enhance the in vitro cellular response. Also, pokeweed mitogen-stimulated B cells from young pigs up to the age of 5 to 6 weeks produced immunoglobulin concentration, which also was not affected by the addition of human interleukin-2 to the in vitro cultures. The blood mononuclear cells obtained from pigs within the first 5 to 6 weeks after birth and incubated with monoclonal antibodies reactive to all T cells (MSA4), helper T cells (74-12-4) or suppressor/cytotoxic T cells (76-2-11) did not yield consistent excess of suppressor/cytotoxic T cells. This observed immunodeficiency cannot be attributed to a simple lack of functional T cells or to an excessive number of suppressor/cytotoxic T cells, but may be a property of the ability of specific T-cell clones to respond t o low concentration of T cell-dependent antigens or may be attributable to the induction of a suppressor T-cell population in response to in vitro stimulation with the polyclonal T-cell-dependent pokeweed mitogen system.

A clinical trial examining the efficacy of 2 drugs for treatment of a natural epizootic of infectious bovine keratoconjunctivitis was performed. The study was conducted in 103 grazing Hereford calves during the summer of 1985. The calves were prospectively and randomly assigned to 1 of 3 groups at the beginning of the study on June 17, and were examined 3 times weekly thereafter until the final observation on August 6. Calves in group 1 (n = 34) were not treated and were used as controls. Calves of group 2 (n = 34) with corneal ulcers were treated with a long-acting oxytetracycline formulation (OTC group). The parenteral treatment was repeated in 72 hours. Affected calves of group 3 (n = 35) were treated topically with furazolidone spray when they developed new corneal ulcers, or when existing lesions worsened during subsequent examination periods (NFZ group). Healing times of the corneal ulcers were reported in 3 ways: the combined times for ulcers present in both eyes of a calf simultaneously (method A), independent times of each ulcer on a calf (method B), and time of the first ulcer for each calf (method C). Censored healing times were examined as left censored (ulcer present at the beginning of the study), right censored (ulcer not healed at the end of the study), or uncensored (true) healing times. The effect that the treatments had on healing times were investigated by use of notched box and whisker plots, life tables, and Cox regression models. The analysis indicated that treatment of calves with either antimicrobial reduced the healing time of corneal ulcers, compared with untreated controls. Calves treated with OTC had shorter periods with ulcers present on both eyes than did NFZ-treated calves. The healing time of the first ulcer on a calf was faster when treated with either antimicrobial than when not treated, but no significant difference between periods for OTC and NFZ treatments was found. Censored healing times were consistently longer than uncensored healing times. Box and whisker plots indicated that both treatments shortened healing times more than those for controls, and OTC shortened healing times more than did NFZ for responses A and B (but not C). Life tables showed that OTC healing times were shorter than those for controls, and NFZ shorter than controls for response B and C (but not A). Cox regression model (for response A) showed a borderline significant difference between times for OTC group and controls, and no significant difference between times for NFZ group and controls.

The distribution of postganglionic autonomic nerve fibers in the lacrimal gland and gland of the third eyelid of dogs was studied by use of histochemical techniques. Adrenergic nerve distribution was identified by use of the sucrose-potassium phosphate-glyoxylic acid technique. A loose network of adrenergic nerves was found throughout the interstitium around acini and blood vessels and in vessel walls. Acetylcholinesterase staining was used to identify cholinergic nerve fibers. A cholinergic distribution pattern around acini and blood vessels similar to the adrenergic pattern was found, although the cholinergic innervation appeared more dense than the adrenergic. In the gland of the third eyelid, mucus-secreting lobules and lipid-secreting lobules appeared to be equally innervated by parasympathetic fibers. These lobules could not be differentiated when the sucrose-potassium phosphate-glyoxylic acid technique was used. The techniques used in this study could not demonstrate whether direct contact was made by either cholinergic or adrenergic nerve fiber with secretory or myoepithelial cells. The presence of both nerve fiber types around acini suggests an interrelationship between the sympathetic and parasympathetic nervous system in lacrimal gland secretion in dogs.

The prevalence and intensity of Cryptosporidium infection were examined in 445 Holstein calves at 10 dairy farms in western Washington, near Seattle. Fifty-one percent (176) of calves in the 7- to 21-day-old age group (n = 342) were positive for oocysts in the feces by carbolfuchsin staining. Prevalence and intensity of infection were highest in calves 8 to 14 days old; prevalence was 60% in this group, and 48% of the Cryptosporidium-positive calves had oocyst shedding at a 4+ level. A seasonal pattern in prevalence was not evident.

Ten commercially available parathormone (PTH) assays were competitively validated, using dilutional parallelism, intra-assay and interassay coefficients of variation, and sensitivity and measured responses of 2 dogs to calcium and EDTA infusions. A 2-site immunoradiometric assay for intact human-PTH was superior to the others for estimating canine-PTH, met the criteria for validity, and was further investigated. A series of sample-handling studies was performed. Serum and plasma samples stored at 24 C lost 15% (n = 5; P less than 0.05) of PTH between 2 and 24 hours. This did not occur at 6 C. The mean PTH concentration of sera from blood samples clotted at 24 C was 6% (P less than 0.05) higher than equivalent EDTA samples. Serum samples stored at 6 and 37 C deteriorated 35% and 100% (n = 5; P less than 0.05), respectively, after 1 week, whereas samples stored at -20 and -70 C for 4 weeks did not deteriorate. There was no significant deterioration of PTH in samples frozen (-40 C) and thawed up to 7 times (n = 5). Parathyroid function testing was investigated by use of 2-hour infusions of disodium EDTA (25 mg/kg/h), 10-minute infusions of calcium gluconate (3 mg of elemental calcium/kg/10 min), and physiologic saline controls (n = 8). Renal function was monitored before and after EDTA infusion by exogenous creatinine clearance. Infusion of disodium EDTA increased mean PTH concentration from 67 (time 0) to 317 and 235 pg/ml at 90 and 180 minutes, respectively (P less than 0.001). Infusion of calcium gluconate decreased mean PTH concentration from 84 (time 0) to 14 and 12 pg/ml at 15 and 60 minutes, respectively (P less than 0.005). There were no observable side effects of the infusions in normal conscious dogs and no differences in exogenous creatinine clearance after EDTA infusion.

Two hundred eighty-eight crossbred feeder pigs were used in 2 trials to determine the effects of feed and/or water deprivation at an auction market, and the effects of restricting the intake of the receiving diet on their serum chemical profile. The study also was designed to assess the value of the serum chemical profile as a diagnostic data base for stress disorders in feeder pigs. Performance data indicated that feeder pigs provided water only at the auction facilities lost significantly more weight than did those provided feed and water. Feeder pigs deprived of both feed and water were not significantly different in body weight from either group. Several serum chemical values (creatinine, triglycerides, cholesterol, blood urea nitrogen, and lactate dehydrogenase) were significantly influenced by feed deprivation, but not by feed and water deprivation. However, only the serum creatinine values were significantly different after the 24-hour post-transport period. There were no significant differences in pig weight or serum chemical values 84 days after pigs had arrived at the finishing unit. The serum chemical profile, widely used in human medicine, appears not to provide a reliable marker for identification of short-term nutritional deprivation, nor for transport stress in feeder pigs.

The ability of Mycoplasma hyopneumoniae to agglutinate RBC was evaluated to develop an in vitro cytadsorption assay. Using swine RBC in a microtitration hemagglutination test, no agglutination or partial agglutination was detected. Comparison of RBC from various other species indicated that improved hemagglutination was obtained with RBC from turkeys. This hemagglutination was detected only when mycoplasma cells used in the assay had been frozen and thawed, heated at 50 C for 30 minutes, or treated with trypsin. Treatment of RBC with trypsin or neuraminidase enhanced hemagglutination. Possible surface lectin activity in M hyopneumoniae was evaluated by use of carbohydrates in a blocking assay; hemagglutination was not inhibited by any of 13 carbohydrates evaluated. Mycoplasma hyopneumoniae convalescent porcine serum and monoclonal antibodies against 2 M hyopneumoniae immunogens of molecular weights of 64,000 and 41,000 inhibited hemagglutination.