Behavioral responses of red-winged blackbirds (Agelaius phoeniceus) to viewing a conspecific distressed by 4-Aminopyridine

4-Aminopyridine (4-AP) is the only pesticide that can be legally used in the US to reduce bird damage in ripening grain fields. Birds that consume grain baits treated with 4-AP (‘Avitrol’ FC-99®) exhibit erratic behavior and emit vocalizations that presumably scare away the rest of the flock. Yet the behavior of 4-A Pintoxicated birds has not been documented, and we do not know how other birds react when observing these intoxicated birds or what these observers learn from their experience. Hence, we examined the behavior of 15 4-A Pintoxicated red-winged blackbirds (Agelaius phoeniceus (L.)) and found that initial signs of intoxication occurred 12.5 min after consumption of the bait, with death following 16.3 min later. During this 16-min intoxication period, birds gradually lost muscular control, making their movements and vocalizations weaker until hardly perceptible. Other captive red-winged blackbirds (‘observers’) gave more alarm calls while witnessing a 4-A P-intoxicated bird in one room of their cage (treatment period) than they did during the pre-treatment period. Immediately after the intoxicated bird died and was removed from the room, the observers' behaviour returned to pre-treatment levels. Broadcasting calls of an intoxicated bird or the placement of an untreated bird in one of the rooms had little effect on the observers' behavior. In another experiment, the placement of a 4-A Pintoxicated or untreated red-winged blackbird or the broadcast of calls of an intoxicated bird at a feed station did not affect the number of free-ranging conspecifics feeding, within sight of, or vocalizing at, these feeder stations. These results suggest that red-winged blackbirds learn little from witnessing a distressed conspecific.     

Ejaculatory failure associated with aortic-iliac thrombosis in two stallions.

Two mature breeding stallions were evaluated because of specific ejaculatory dysfunction, and each was found to have aortic-iliac thrombosis occluding 60 to 70% of the aortic lumen. In each case, the stallion had strong libido, normal mounting, and vigorous initial thrusting. With continued exertion, thrusting became weak and dismount was awkward. Treatment aimed at maximizing sexual arousal before mounting and reducing hind limb pain and exertion during breeding allowed these stallions to continue breeding. A program of gradually increasing daily exercise also was associated with improved breeding performance during subsequent breeding seasons. In cases of specific ejaculatory dysfunction, aortic-iliac disease should be included among the differential diagnoses.     

Small intestine and small colon neuropathy in equine dysautonomia (grass sickness)

The number of neurons in the coeliacomesenteric ganglia and the myenteric and submucosal plexuses of the jejunum, ileum and small colon, and the pathological changes induced in them, were studied in various types of equine dysautonomia. In all forms of dysautonomia, severe and extensive neuron loss and damage occurred in the ileum. In acute and subacute dysautonomia, jejunal neuron loss and damage were severe, but in chronic cases significantly less loss or damage occurred. The damage followed the same pattern in the small colon but it was always less obvious than in the jejunum. The distribution of the damage was uniform within a segment of the intestine. In fatal cases of dysautonomia, the clinical severity and duration of illness seems, in most instances, to be related to the amount of neuronal disruption occurring in the jejunum. Severe disruption results in acute/subacute dysautonomia, while milder damage leads to the chronic form.No case of dysautonomia was encountered in which enteric neuron loss and damage occurred without significant neuronal disruption also occurring in the coeliacomesenteric ganglia.Ileal neuronal damage and loss are not invariably worse than that in the jejunum, and the possible reasons for this, together with the relationship between neuronal damage and possible causes of dysautonomia, are discussed.Abbreviations H&E haematoxylin and eosin Deceased. Formerly of the Moredun Research Institute, 408 Gilmerton Road, Edinburgh, EH17 7JH, UK     

Excision of the distal sesamoid bone for treatment of infection of the digit in a heifer.

An 8-month-old Holstein heifer was evaluated for right hind limb lameness of 3 weeks' duration. Diagnoses were osteomyelitis and fracture of the distal sesamoid bone, septic arthritis of the distal interphalangeal joint, and osteomyelitis of the third phalanx. After excision of a section of tissue from the plantar aspect of the digit and partial section of the deep digital flexor tendon, the distal sesamoid bone was excised. The third phalanx was curetted, and the surgical wound was lavaged. Twenty months after surgery, the heifer was fully weightbearing on the affected digit. Surgical exploration of the digit should be considered an alternative to claw amputation in cattle that have severe digital infections.     

Correlated Response to Selection for Protein Yield in Oats After Three Cycles of Recurrent Selection

Three oat (Avena saliva L.) populations (i.e., lines of descent), high grain yield (HG), high protein content (HP), and high protein yield per se (HGP), each developed by three cycles of S, recurrent selection, were evaluated for the effect of selection for groat-protein yield upon other agronomic traits. Selections making up the HG line of descent had high protein yield primarily due to high grain yield, and those selected for HP had high protein yield due to both high protein content and high grain yield. Selection in HGP was on the basis of protein yield per se. Selection caused increases in bundle weight, harvest index, vegetative growth rate, and seed number in all lines of descent. Heading date, plant height, and seed weight were unaffected, whereas groat percentage and test weight were decreased in HP and HGP. Heritabilities were high for heading date, plant height, test weight, and seed weight, moderate for harvest index and bundle weight, and low for groat percentage. Genetic variability generally declined from CO to C3 for all traits. Groat-protein yield and amount of protein per groat increased in all lines of descent. In HG, the increase in groat weight was due primarily to increases in the nonprotein fraction, with groat-protein content actually decreasing. In HGP, groat weight increased due to increases in protein and nonprotein fractions, and groat protein content remained constant. In HP, groat weight and amount of nonprotein per groat decreased, thus increasing groat-protein content. Three cycles of recurrent selection resulted in oat lines with groat-protein yields significantly higher than the highest lines from CO. Utilization of index selection may be desirable to obtain populations of greater breeding value.     

Restoration of the anterior dentition of a Canadian beaver (Castor canadensis)

An eight-year-old beaver lost one of its upper central incisors through unknown causes. As the anterior teeth of this species continually erupt in a similar manner to rodents' teeth, the unopposed lower incisor had over-erupted perforating the palate and entered the nasal cavity. The height of the lower incisor tooth was reduced and a cobaltchromium alloy bridge was constructed which was attached to the remaining upper incisor. The occlusal surface of the bridge was of sufficient width that both incisors could contact it. It was cemented into place with composite resin cement and cross-pinned through the labial surface of the metal into the tooth substance. It is unknown how such treatment will affect the biological processes underlying the continually erupting incisor and the animal is being monitored for any adverse effects.     

Scanning electron microscopy of corrosion casts of the optic nerve microcirculation in dogs

Scanning electron microscopy of vascular corrosion casts of the optic nerve region in normal and glaucomatous Beagles demonstrated that the blood supply to the laminar optic nerve is derived from short posterior ciliary arteries, cilioretinal arteries, and longitudinal pial vessels. The short posterior ciliary arteries formed a ring of striated pillars around the scleral canal. The central retinal artery was not present in the dog. Differences between the casts in normal and glaucomatous dogs were not detected.     

Multiplication of Xanthomonas campestris pvs secalis and translucens in host and non-host plants (rye and barley) and development of water soaking1

Multiplication of the rye-specific and barley-specific pathovars secalis and translucens, respectively, of Xanthomonas campestris (earlier named Xanthomonas translucens f. sp. cerealis) was determined in two rye and two barley cultivars. Fresh bacterial cultures were suspended in boiled tap water, adjusted to about 3 × 10⁷ cfu ml^?1 and infiltrated into the mesophyll of young leaves. In the compatible combinations, a generation time of 1.7–2.1 h was determined. Significantly higher multiplication rates than in incompatible combinations were not observed before 3 or 4 days after inoculation. At this time, the first small water-soaked areas appeared. Bacteria multiplied up to the seventh day after inoculation, reaching a maximum of at least 10⁹ cells per cm², the same time at which the water-soaked areas had reached their maximum size. Thus, the rate of bacterial multiplication paralleled with the development of the water-soaked areas. In the incompatible combinations, nearly the same generation times were detected during the exponential growth phase. However, water-soaked areas did not appear, and the final bacterial concentration ranged from 1:1000 to 1:100 of that determined in compatible combinations. A distinct early lag phase, characterized by a decrease of the bacterial population down to 1:100 of the starting concentration, was detected in all cases.     

Determination of sulfamethazine and trimethoprim in liquid feed premixes by HPLC and diode array detection, with an analysis of the uncertainty of the analytical results.

Sulfamethazine (SMZ) and trimethoprim (TMP) are antibacterials used in veterinary practice. This paper describes a method for their determination in veterinary liquid feed premixes that is based on liquid chromatography with diode array detection. Gradient elution with methanol and ammonium acetate achieved excellent separation of the two analytes within 15 min without any interference from the matrix. Absorbance of the column effluent was monitored at 264 nm for SMZ and at 230 nm for TMP. Detailed analyses of the uncertainties of determinations afford estimated expanded uncertainties of, respectively, 0.2 and 0.1 w/v % for typical SMZ and TMP concentrations of 10.7 and 2.1 w/v %, respectively. At the lower end of the calibrated range of the method, the dominant source of uncertainty is the preparation of standards and the construction of the calibration line.