Causes of death and illness in the native sheep of North Ronaldsay, Orkney. I. Adult sheep

Post-mortem examinations on 71 native sheep found dead on the island of North Ronaldsay, Orkney in four visits between April 1983 and July 1985 were carried out. The sheep in this almost feral flock have access to a small area of unmanaged moorland pasture but are otherwise restricted to the foreshore where they subsist largely on Laminaria spp. and other seaweeds. Young adult animals died largely of heavy parasite burdens combined with inadequate nutrition, while the older sheep often starved because of severe dental disease precipitated by heavy deposits of tartar on the cheek teeth--rarely seen in sheep on a more conventional diet. Other underlying metabolic conditions, such as the extensive mineralization of the kidney medulla in many mature sheep, may be debilitating. The pathological findings suggest that adaptation to the peculiar environmental rigours and dietary restrictions on North Ronaldsay is less complete than has previously been assumed.     

Noninvasive monitoring of doxorubicin cardiotoxicity: a pilot study of two dogs

The cardiotoxicity of anthracycline anticancer agents, most notably doxorubicin, limits their use in treating a wide variety of cancers. Currently available methods for assessment of anthracycline‐induced cardiotoxicity (AIC) often lack specificity and sensitivity. The purpose of this pilot investigation was to determine noninvasive diagnostic methods that are predictive for AIC. Two mongrel dogs were anesthetized for injection of doxorubicin (22.5 mg) directly into the left coronary artery. Doxorubicin injection was repeated 2 weeks later. Dogs were followed for 12 weeks or until heart failure was documented. Dogs were monitored before and at serial time points after doxorubicin using echocardiography and signal‐averaged electrocardiography as well as ambulatory ECG monitoring. Blood was also collected for measurement of cardiac troponin I and T concentrations. Doxorubicin was readministered at 6 and 12 weeks after the second injection, as interim data analysis did not reveal adequate evidence of cardiomyopathy. Dog‐1 appeared to be more sensitive than Dog‐2 to AIC based upon gradual changes in variables of cardiac function and earlier time to failure (113 days). In contrast, Dog‐2 had inconsistent changes in cardiac function and a longer time to failure (139 days). Dog‐1 also had greater peak plasma cardiac troponin I levels (17.96 ng/ml) as compared to peak levels in Dog‐2 (4.08 ng/ml). In addition, Dog‐1 had increased ventricular extrasystolic contractions (VE)(0/day at baseline, 443/day one week prior to death), whereas dog‐2 showed very few VE's throughout. Spectral analysis of ECG data also revealed a significant decrease over time in total spectral power in Dog‐1 from 37,148 at baseline to 603 msec²/Hz one week prior to death, indicating decreased parasympathetic tone. Endomyocardial biopsies revealed minor changes despite significant clinical abnormalities. These data indicate differences in susceptibility to AIC between Dog‐1 and Dog‐2, and suggest a role for these noninvasive measures in monitoring the heart during chemotherapy.     

Control of the weaning-to-estrus interval in sows using gonadotropins and prostaglandins during lactation.

Two experiments were conducted to examine the effectiveness of various strategies using gonadotropins to induce ovulation during lactation as a means of controlling the weaning-to-estrus interval in sows. The objective of Exp. 1 was to examine the efficacy of various gonadotropin regimens for induction of ovulation during lactation. Primiparous (n = 60) and multiparous (n = 83) crossbred sows were assigned, before farrowing, to one of four treatments: no injection (control); 1,000 IU hCG on d 0 (hCG-0; d 0 = day of farrowing); P.G. 600 + 1,000 IU hCG 4 and 7 d after farrowing, respectively (hCG-7); or P.G. 600 + 1,000 IU hCG 11 and 14 d after farrowing, respectively (hCG-14). Sows were weaned on 18 +/- 2 d after farrowing and monitored daily for estrus via exposure to mature boars. The criterion for determining the induction of ovulation was a sustained increase in serum progesterone concentrations above 4.0 ng/mL. The most consistent response to exogenous gonadotropins was on d 0, with an 80% response in primiparous sows (12/15) and a 71% response in multiparous sows (15/21). Weaning-to-estrus intervals for multiparous sows were longer (P = .05) for hCG-14 and hCG-7 than for control and hCG-0 sows. Weaning-to-estrus intervals for primiparous sows were longer (P = .05) for the hCG-14 than for the hCG-0 treatment. The objective of Exp. 2 was to ascertain the effects of postpartum treatment with hCG (1,000 IU) on d 0 and PGF2alpha (10 mg) at d 14 on the weaning-to-estrus interval in multiparous sows weaned at d 14 after birth. Before farrowing, sows (n = 60) were randomly assigned to one of four treatments: positive control, weaning at d 21; negative control, weaning at d 14; hCG within 24 h after farrowing, weaning at d 14; or hCG within 24 h after farrowing and PGF2alpha at weaning, weaning at d 14. Weaning-to-estrus intervals were longer (P = .05) in sows receiving PGF2alpha than in the other treatments. Results indicate that it is possible to induce ovulation immediately after farrowing, using a single injection of hCG, and this strategy can be used to uncouple weaning from the resumption of reproductive activity. However, the administration of PGF2alpha at 14 d after farrowing did not consistently cause regression of the induced corpora lutea.     

Use of pneumocystoplasty for overinflation of the swim bladder in a goldfish

A Ryukin goldfish was evaluated because of a 6-month history of progressive abdominal distention and positive buoyancy. Overinflation of the swim bladder was diagnosed, and the fish was anesthetized with tricaine methanesulfonate. Archimedes' principle was used to determine the volume of swim bladder that was removed surgically. The caudal swim bladder was exteriorized through an abdominal incision and 2 surgical clips were placed across it to limit its size. After surgery, the fish remained in a state of negative buoyancy in sternal and lateral recumbency on the bottom of the tank. Sutures were removed 15 days after surgery, but the fish died 24 days after surgery. A full necropsy could not be performed because of autolysis of the tissues, but the surgical clips and the swim bladder appeared unremarkable. Pneumocystoplasty may be a viable treatment for this condition.     

FACIAL FIBROSARCOMA IN TWO COWS

Fibrosarcoma is a common tumor affecting bone, but is uncommon in cows, Reported here are two bovine cases of facial fibrosarcoma that were very invasive.     

Influence of footing surface on mounting and other sexual behaviors of estrual Holstein cows

Seven ovariectomized Holstein cows, treated sequentially with progesterone and estradiol benzoate to induce estrus, were used to determine whether cows showed a preference for mounting and displaying other sexual behaviors toward estrual or nonestrual cows tied on dirt or concrete surfaces. Preference tests were conducted in a test area that consisted of equal-sized concrete and dirt surfaces; two cows, designated A and B, were tied on the two surfaces, one on either side. Cows A and B were treated so that on each of four test days both were estrual, only A was estrual, only B was estrual or neither A nor B were estrual. On each test day, five estrual test cows were introduced individually into the test area for two 30-min test periods. During the first test period, tied cow A was on concrete and tied cow B was on dirt, but during the second test period, their positions were switched. Test cows were able to move freely from surface to surface and to interact with tied cow A or B. Estrual test cows spent 21.6 +/- 1.4 min of each 30-min test period on dirt, regardless of the estrual status of the cow tied on concrete or dirt. Mounting activity was 3- to 15-fold greater on dirt than on concrete when there was an estrual cow tied on dirt, regardless of the estrual status of the cow on concrete. Mounting activity was fourfold greater on concrete than on dirt when there was a tied estrual cow on concrete and a tied nonestrual cow on dirt.(ABSTRACT TRUNCATED AT 250 WORDS)     

Genetic and Environmental Correlations Among Female Fertility Traits and Milk Production in Different Parities of Swedish Red and White Dairy Cattle

The main objective of this study was to estimate genetic correlations between fertility and production traits in first, second and third lactations as well as between fertility traits measured in the same way at different ages. The fertility traits studied were: number of inseminations per service period, number of treatments for reproductive disturbances, interval between first and last inseminations, interval between calving and first insemination, and interval between calving and last insemination. Early milk production was measured as the average of the energy-corrected milk yield at the second and third monthly testdays in a lactation. The number of records was approximately 450 000, 350 000, 180 000 and 75 000 in the heifer period, first, second, and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and sire of the cow was applied. To reduce the effect of ongoing selection, 305-days kg protein production in first lactation was included as a variate in all of the analyses. Correlations between the herd-year effects indicated that factors of herd-year level conducive to increased production had a tendency to increase the number of inseminations as well as the number of reproductive treatments, although there was an earlier start and termination of the insemination period. Genetic correlations between fertility traits and production were in the range of 0.2-0.4, all of them unfavourable and higher at later parities. The genetic correlations between fertility traits in the heifer period and the same traits in first lactation were 0.7. Genetic correlations between the first and second lactation varied between 0.7 and 0.9, and between the second and third lactation they were all 0.9 or higher. In conclusion, fertility and production traits need to be selected for simultaneously if fertility is going to be maintained along further genetic improvement on production, and such selection should include fertility results from lactating cows.     

Acute viral hepatitis in California sea lions

Acute viral hepatitis was diagnosed in five California sea lions (Zalophus californianus) stranded along the Los Angeles coast. Light microscopy revealed large nuclear inclusion bodies in hepatocytes. Electron microscopy provided evidence that these inclusion bodies were composed of adenovirus-like virions. Attempts to grow the virus in cell culture systems were unsuccessful.