Search PubMed⌕ Search

Biomedical subjects

G J Gallivan

Publications and source records attributed to G J Gallivan.

35 records · Page 2Linked to original sources
PubMed1989

Comparative ventilation and gas exchange in the horse and the cow.

Ventilation and gas exchange were studied in healthy, adult horses and cows, two large species with different lung structures and different breathing patterns. The oxygen uptake (VO2), carbon dioxide output (VCO2), respiratory rate (fR), minute ventilation (VE), alveolar ventilation (VA), alveolar oxygen pressure (PAO2), and VE/VO2 ratio were higher in the cows, while the tidal volume (VT) and physiological dead space (VD) were larger in the horses. The arterial blood gases, alveolar-arterial oxygen pressure difference (PAO2-PaO2) and VD/VT ratio did not differ between the two species. The higher VO2 in the cows was most likely due to the energy cost of standing, and possibly to a higher cost of digestion. The higher VE, VA, VE/VO2 and PAO2 were most likely secondary to the increased VO2 and the slightly higher respiratory exchange ratio (R) in the cows. In contrast to hypotheses based on allometric equations, the PAO2 of horses and cows did not appear to differ from that of smaller mammals. The VD was larger than that predicted from allometric equations, and even though the VD/VT ratio (0.50) was lower than the previously reported values for horses and cows, it was significantly larger than the predicted weight-independent value of 0.36. Re-examination of the data used to derive the equation for VD raised questions as to the validity of this equation, and it is suggested that caution be exercised in the use of allometric equations for prediction.

Animals↗
PubMed1988

Reproducibility of pulmonary mechanics measurements in dairy cattle.

The reproducibility of pulmonary mechanics measurements in dairy cattle was examined using two study designs. In design A measurements were made with six cows on two days, and in design B measurements were made with four cows on six days. The mean coefficients of variation for within-day measurements for individuals ranged from 9.2 to 25.9% indicating considerable within-day variability. In design A there were no significant differences between days (P less than 0.05) for any measured variable for the group, but there were often significant differences between the two days for individuals. In design B there were significant cow-day interactions for all variables, again indicating significant differences between days for individuals. There were significant differences between days for the group for respiratory rate, and duration of inspiration and expiration. Both the interactions and differences between days appeared to be random. The high variability and limited reproducibility of pulmonary mechanics measurements, particularly in individual animals, indicate the need for caution in the interpretation of pulmonary mechanics measurements in dairy cattle.

Analysis of Variance↗
PubMed1986

Heart rates and gas exchange in the Amazonian manatee (Trichechus inunguis) in relation to diving.

Unrestrained Amazonian manatees (Trichechus inunguis) maintained a constant heart rate during diving and exhibited a slight tachycardia during breathing. 'Forcing' the manatees to dive caused a marked bradycardia. They exhibited a more pronounced tachycardia during breathing after 'forced' dives and hyperventilated during recovery dives. Manatees are capable of dives exceeding 10 min duration without having to resport to anaerobic metabolism, and even after 10 min dives recover within 3-4 short dives. The ability of manatees to make long dives, in spite of relatively poor O2 stores, is due to their low metabolic rate, while the rapid recovery is aided by their high CO2 stores which minimizes CO2 storage in the body. In manatees the changes in alveolar O2 and CO2 pressure (PAO2 and PACO2) in relation to dive time are slower and more variable than in other marine mammals. The lower rate of change is probably due to the manatees' reduced metabolic rate, while the greater variability is due to their breathing pattern, in which both ventilation and body gas stores influence alveolar gases.

Animals↗
PubMedDate not supplied

Clinical, biochemical, and hematologic evaluation of normal dogs after administration of rabbit anti-dog thymocyte serum.

Renal allografting is the only long-term alternative to euthanasia in dogs with end-stage kidney disease. The purpose of this study was to determine the clinical, biochemical, and hematologic effects of rabbit anti-dog thymocyte serum (RADTS) in normal dogs and to develop a safe and practical route of administration before its use in an allograft immunosuppressive protocol. Thirteen mongrel dogs were divided into three groups; each received RADTS subcutaneously, intramuscularly, or intravenously. The inflammation and pain associated with subcutaneous administration was unacceptable. A significant (p < or = .05) leukopenia and lymphopenia developed in all dogs, regardless of the route of administration of RADTS. Thrombocytopenia was a consistent finding after intravenous administration and with high doses given intramuscularly. Both the intravenous and intramuscular routes were well tolerated by all dogs with minimal or no discomfort. Serum creatinine was unchanged, whereas serum alanine aminotransferase activity increased in one dog. There were no histologic changes in any of the kidneys examined.

Animals↗
PubMedDate not supplied

Pesticide risk reduction on crops in the Province of Ontario.

We analyzed the changes in pesticide use and risk in the Province of Ontario, Canada, from 1973 to 1998 to monitor the success of Food Systems 2002, a program to reduce pesticide use by 50%. Pesticide risk was calculated by multiplying the amount of pesticide used (kilograms of active ingredient) by the Environmental Impact Quotient (EIQ), a score for the potential risk of pesticides to farmworkers, consumers, and the environment. Pesticide use increased by 46% from 1973 to 1983. From 1983, the baseline year for Food Systems 2002, to 1998, pesticide use decreased by 38.5% and risk declined 39.5%. The reductions in pesticide use and risk were primarily on corn (Zea mays L.) and tobacco (Nicotiana tabacum L.), the crops with the highest pesticide use in 1983. Total pesticide use on soybean [Glycine max (L.) Merr.] did not change, but the mean application rate (kg ha(-1)) decreased by 57%. Corn and soybean account for 65% of pesticide use, but have a relatively low pesticide use and risk per hectare and per tonne of production. Total pesticide use on tobacco, fruits, and vegetables was lower than on corn or soybean, but the pesticide use and risk per hectare were much higher. Small reductions in pesticide use on corn and soybean may allow a 50% reduction in pesticide use, but greater reductions in risk can be achieved by reducing the use of "high risk" pesticides on fruit and vegetables.

Agriculture↗