Hydroxyl radical concentrations measured in ambient air

Diurnal variations in the hydroxyl radical concentration of ambient air were measured for the first time by the technique of laser-induced fluorescence.     

THE USE OF ELECTROCARDIOGRAPHY IN THE DIAGNOSIS OF POOR RACING PERFORMANCE IN THE HORSE

Electrocardiograms were reocrded from 153 racehorses and 10 Olympic three-day-event horses. The horses were then grouped into those presented for routine examination, those in which there was a complaint of poor performance, those going to the Montreal Olympics, and those with upper respiratory tract abnormalities. When the ECGs of the four groups were compared on the basis of detection of abnormality, it was found that 93.2% of the poor performance group showed abnormalities of various types. The routine examination group showed 21.1% of horses with abnormal ECGs, and over half of these have been followed to the point where it can be said they raced unsuccessfully. In particular, this applied to those horses with T wave abnormalities in 4 or more leads, and to those with intraatrial block. There were significant T wave changes in 50% of the Olympic horses, and 43.7% of horses with laryngeal hemiplegia showed abnormality. While it can be concluded that T wave changes are highly significant findings in an ECG, it is also true that modification of the training programme is a way of helping trainers to get the best out of horses which might otherwise have a serious limitation of their performance potential.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Early growth and environmental implications of dietary zinc and copper concentrations and sources of broiler chicks

1. Environmental accumulation of zinc and copper is becoming a concern in areas having intensive animal production. This study examined performance and excretion of broiler chicks given diets supplemented with graded concentrations of zinc and copper from three different sources. 2. Two experiments were conducted, each utilising 570 1-d-old chicks. In Experiment 1, chicks were given diets containing supplemental zinc concentrations from 40 to 120 mg/kg supplied as zinc sulphate, a zinc amino acid complex (Availa Zn), or a combination of zinc sulphate and Availa Zn with each contributing one-half of the total supplemental zinc. In Experiment 2, broiler chicks were given diets with graded concentrations of supplemental copper ranging from 4 to 12 mg/kg from copper sulphate, a copper amino acid complex (Availa Cu), or a combination of copper sulphate and Availa Cu with each contributing one-half of the total supplemental copper. 3. During the 17-d experimental period, mineral concentration or source did not influence body weight, feed conversion, or the incidence of mortality from 1 to 17 d. 4. Decreasing dietary zinc concentration from 120 to 40 mg/kg reduced zinc excretion by 50%. 5. Copper excretion was decreased by 35% as supplemental copper was reduced from 12 to 4 mg/kg. 6. Reducing dietary zinc and copper concentrations can potentially decrease the accumulation of heavy metals in the environment without compromising bird performance.     

Accuracy of bovine pregnancy detection using transrectal ultrasonography at 28 to 35 days after insemination

OBJECTIVE: To estimate the accuracy of real-time ultrasonography to detect pregnancy in dairy cows at 28 to 35 days after insemination. METHODS: Cows that did not return to oestrus between 18 and 24 days after a first insemination (n = 526) were examined by transrectal ultrasonography from 28 to 35 days after insemination. Pregnancy was confirmed by the observation of a foetus, but fluid in the uterine horn and the presence of embryonic membranes were also noted. When pregnancy was not confirmed by the observation of a foetus, a second examination 7 days later, confirmed these remaining cows as pregnant or not pregnant to the first insemination. Detection of pregnancy at this early examination was compared with manual transrectal pregnancy examination performed 10 to 13 weeks after insemination (13-week examination). RESULTS: There were 44% of cows that were pregnant to the first service, 34% that had returned for a second service 18 to 24 days after the first insemination, and 20% of cows that were not pregnant, and had not returned normally for a second service (non-pregnant, non-return) within 24 days of their initial insemination. The presence of a foetus at 28 to 35 days after insemination was accurately predicted by a simplified method where uterine fluid accumulation and embryonic membranes were observed. Foetal loss between the early detection and the 13-week examination (9% of pregnancies) indicated that 28 to 35 days post insemination was too early to reliably detect pregnancy. CONCLUSION: Early examination of pregnancy with transrectal ultrasonography is an accurate method to identify non-pregnant, non-return cows. The examination can be simplified by the observation of uterine fluid accumulation and embryonic membranes, as opposed to the more involved process of observing the foetus.