Convergent morphological evolution detected by studying proteins of tree frogs in the Hyla eximia species group

Protein studies have uncovered an apparent case of convergent evolution among North American tree frogs. The species Hyla eximia and Hyla regilla are so similar in external morphology that the "wrightorum" subspecies is assigned by some authorities to H. eximia and by others to H. regilla. Yet microcomplement fixation experiments show that "wrightorum" albumin, though virtually indistinguishable from authentic H. eximia albumin, differs as much from H. regilla albumin as from albumins of species outside the genus Hyla, such as Acris crepitans. The morphological resemblance of "wrightorum" to H. regilla is thus probably due to convergence.     

Effects of furosemide on the racing times of Thoroughbreds

The effects of furosemide on the racing times of 79 horses without exercise-induced pulmonary hemorrhage (EIPH) and 52 horses with EIPH were investigated. Racing times were adjusted to 1-mile equivalent racing times by 2 speed handicapping methods, and analysis of covariance was used to adjust actual racing times by winning time and distance for each race. All 3 methods of determining racing time indicated that geldings without EIPH had significantly faster racing times (P less than 0.05) when given furosemide before racing than when furosemide was not given before racing. Females and colts without EIPH were determined to have faster racing times when furosemide was given before racing, but the difference was not significant. Geldings with EIPH had significantly faster racing times (P = 0.0231) when given furosemide before racing, as determined by one of the speed handicapping methods. There was a strong correlation (range 0.9314 to 0.9751) between the 1-mile equivalent racing times, as determined by the 2 speed handicapping methods for horses with and without EIPH. Furosemide failed to prevent the development of EIPH in many horses that were previously considered to be EIPH-negative. When given furosemide, 62 (25.3%) of 235 EIPH-negative horses were EIPH-positive after racing. Furosemide had questionable efficacy for prevention of EIPH in known EIPH-positive horses. Thirty-two (61.5%) of 52 EIPH-positive horses given furosemide before a race remained EIPH-positive after that race.     

AORTO-CARDIAC FISTULAS IN SEVEN HORSES

This report describes the history, clinical, electrocardiographic and echocardiographic findings, treatment, outcome, and post-mortem findings in seven horses with aorto-cardiac fistula. Affected horses included 5 stallions, one gelding and one mare; 2 each of the Thoroughbred, Arabian and Standardbred breeds and one Thoroughbred-cross with a mean ± s.d. age of 12 ± 4 years, range 6–18 years. The presenting sings were acute distress (four horses), exercise intolerance (two horses) and the lesion was detected during a routine examination in one horse. Five horses had monomorphic ventricular tachycardia on admission and one other had a history of this arrhythmia. Five horses had a characteristic continuous murmur loudes in the right fourth intercostal space. Echocardiography (six horuses) and/or post-mortem examination (four horses) revealed the horses had aorto-cardiac fistulas arising from the right aortic sinus in all five horses in which the site was recorded. Two horses had ruptured aneurysmall dilatations of the aortic wall at this site. Fistulas extended into the right ventricle in four horses; the right atrium in two horses, the left ventricle in one horse, and five horses had dissecting tracts in the septal myocardium. Horses survived for periods ranging from 24th to 4 years. Aorto-cardiac fistula should be considered in the differential diagnosis for horses presenting with acute distress, bounding arterial pulse, a right-sided continuous murmur and/or monomorphic ventricular tachycardia, particularly in middle-aged or older stallions. Echocardiography is the technique of choice for confirming the diagnosis and demonstrating accompanying cardiac changes.     

Effect of dietary gestation and lactation protein levels on reproductive performance and body composition of first-litter female swine

A 2 X 3 factorial split-plot experiment was conducted to determine the effect of dietary protein on the performance and calculated body compositions of 45 first-litter sows using the D2O dilution technique at various reproductive stages. Animals were initially fed 1.82 kg daily of a 14% protein diet to 14 d post-coitum. Subsequently, two gestation protein levels (5 or 14%) were daily fed at 1.82 kg from 15 d postcoitum to parturition with three dietary lactation protein levels (5, 14 or 23%) fed from parturition to 28 d postpartum. Maternal body compositions were determined at 17, 35, 70, 85 and 105 d postcoitum and 7, 14 and 28 d postpartum using prediction equations reported previously. Gravid sows demonstrated higher maternal tissue accretion of all body chemical components from 14 to 70 d than from 70 to 105 d postcoitum. Sows fed the 5% protein gestation diet had more maternal fat but less protein accretion than those fed the 14% protein at each measurement interval. During the last trimester, those sows fed the 5% protein diet catabolized body protein reserves. Gravid sows fed the 14% protein gestation diet catabolized more maternal protein and water between 105 d postcoitum and 7 d postpartum than those fed the 5% protein diet. Litter and pig birth weights were lower and postpartum mortality higher for sows fed the 5% rather than the 14% protein gestation diet. Sows fed the 5% protein lactation diet mobilized more maternal tissue, particularly fat, between 7 and 28 d postpartum than those fed 14 or 23% protein lactation diets. These results suggest that labile maternal body protein reserves are used by gravid and nursing dams to fulfill reproductive needs and that dietary protein sequence affects the dam's performance and body composition.     

Dietary calcium and phosphorus for lactating swine at high and average production levels

An experiment utilizing 198 first-and 77 second-litter sows evaluated the effects of five dietary Ca:P levels at two litter sizes (six to seven or 11 to 12 pigs/litter) over a 21-d lactation period for two parities. Lactation dietary P levels ranged from .50 to .90% in .10% increments with Ca concurrently increased in a 1.3:1 ratio using dicalcium phosphate and limestone as the inorganic mineral sources. A 14% protein, corn-soybean meal diet was formulated with .80% Ca and .60% P for gestation while lactation diets varied in their Ca and P contents. Randomly selected sows from each treatment group and parity were slaughtered with various bones collected for analyses. A counterpart set of nongravid gilts remained on trial and were slaughtered at the end of the two-parity period with bones collected. Sow dietary mineral level did not affect sow or pig performance, nor was there an interaction between dietary mineral level, parity or litter size nursed. Serum and milk Ca, P or Mg were unaffected by dietary Ca:P at 7 or 21 d of lactation, but milk Ca and P increased from parity I to II. Percent rib and vertebra bone ash decreased from parity I to II for sows nursing the larger litters; other bones were unresponsive to dietary mineral level. Femur thickness decreased from parity I to II but was not influenced by dietary Ca:P level. Bone-bending moment of the ribs, metacarpals and metatarsals were not influenced by diet, but a lower metacarpal bending moment was observed for sows nursing larger litters. All bones from nongravid females had higher percentage of bone ash, bending moment and shaft thickness when compared with reproducing sows. These results suggest that reproductive state (i.e., reproducing vs non-reproducing), litter size and parity affected sow Ca:P mineral skeletal reserves more than dietary Ca:P levels.     

FIRST-PASS RADIONUCLIDE ANGIOGRAPHY IN THE DIAGNOSIS OF AORTOILIAC THROMBOEMBOLISM IN A HORSE

First-pass radionuclide angiography of the terminal aorta was performed in 3 normal horses and a 6-year old Standardbred intact male with aortoiliac thromboembolism. Thromboembolism caused chronic bilateral hind limb lameness, more severe in the right hind limb, was detected by rectal examination, and confirmed using transrectal ultrasonography. Using ^99mTc-HDP, first-pass radionuclide angiography was combined with hind limb and pelvis bone(delayed) scintigraphy and revealed marked reduction in blood flow through both external iliac arteries and absence of blood flow in the internal iliac arteries. Quantitative analysis showed a decreased activity in the right iliac vessels in the clinic patient consistent with reduced blood flow when compared to control horses. First-pass radio-nuclide angiography provided a method to obtain diagnostic images of the terminal aorta and branches and a method to diagnose aortoiliac thromboembolism in the horse.     

Albumin and Australian frogs: molecular data a challenge to speciation model

Vertebrate speciation in the southwest of Australia has long been viewed as resulting from multiple invasions of eastern source stocks during the Pleistocene. Microcomplement fixation studies of serum albumin evolution in frogs of the genus Heleioporus provide the first hard data on age and phylogenetic relationships among species in this genus and lead to rejection of the multiple invasion model in favor of speciation occurring in Western Australia. The albumin molecular clock was used to estimate that the species divergences in this genus occurred between 4 million to 12 million years ago in the late Tertiary (Pliocene-Miocene), rather than in the Quaternary (the last 2 million years).