The fox (Vulpes vulpes) as a reservoir for canine angiostrongylosis in Denmark. Field survey and experimental infections.

Until recently, Angiostrongylus vasorum was not considered to be an endogenous Danish parasite, since demonstration of this worm had been confined to necropsy findings in 2 dogs, both of which had visited France. During the last 2 years, however, clinical cases have been diagnosed among a considerable number of Danish dogs, none of which had ever been outside Denmark. All these cases have occurred north of Copenhagen, where an endemic focus seems to exist. In this field survey A. vasorum was found for the first time in wild Danish red foxes. Furthermore, experimental infections showed that the parasite can be transferred between foxes and dogs. Consequently, the wild fox population must be considered a potential reservoir for transfer of A. vasorum to domestic dogs.     

Effects of breed and retained heterosis on milk yield and 200-day weight in advanced generations of composite populations of beef cattle.

Retained heterosis in F2 cows nursing F3 progeny was evaluated in 3-, 4-, and greater than or equal to 5-yr-old cows. Traits evaluated included milk yield at three stages of lactation and 200-d weight of progeny. Breed effects were evaluated in the nine parental breeds (Red Poll [R], Hereford [H], Angus [A], Limousin [L], Braunvieh [B], Pinzgauer [P], Gelbvieh [G], Simmental [S], and Charolais [C]) that contributed to the three composite populations (MARC I = 1/4 B, 1/4 C, 1/4 L, 1/8 H, 1/8 A; MARC II = 1/4 G, 1/4 S, 1/4 H, 1/4 A; and MARC III = 1/4 R, 1/4 P, 1/4 H, 1/4 A). Breed effects were significant for 12-h milk yield, estimated 200-d milk yield, and 200-d weight of progeny. Herefords were lowest (P less than .05) for 12-h milk yield and estimated 200-d milk yield, and Braunvieh produced significantly more milk than all breed groups except Pinzgauer and Simmental, for which the difference approached significance. The correlation among breed group means (nine parental breeds and three composites) for 12-h milk yield with 200-d weight of progeny was .91. When 200-d weight was adjusted to a common estimated 200-d milk yield, Hereford, Angus, Red Poll, and Limousin did not differ (P greater than .05); all were significantly lighter than Braunvieh, Pinzgauer, Gelbvieh, Simmental, and Charolais, which did not differ (P greater than .05) from each other.(ABSTRACT TRUNCATED AT 250 WORDS)     

Orbital chondroma rodens in a dog.

A chondroma rodens involving the superficial medial aspect of the right orbit was diagnosed in a 9-year-old dog referred because of chronic unilateral epiphora. Examination revealed several ophthalmic abnormalities attributable to a space-occupying mass in the superficial medial aspect of the orbit. The mass was excised; however, regrowths at the primary site necessitated additional surgical interventions. The dog was given radiation therapy, which provided encouraging results. Subtle histologic differences as well as differing epidemiologic features suggest that chondroma rodens is not analogous to the human entity of juvenile aponeurotic fibroma, to which it has been compared in the past.     

Relationship of growth hormone, prolactin and thyrotropin secretion to individual and progeny performance of Hereford bulls

Six Hereford bulls from a line selected with an index of body weight and muscling score were compared with six bulls from a control line to determine if increased growth in the selected line was associated with changes in plasma levels of growth hormone (GH), prolactin (PRL) and (or) thyrotropin (TSH). The predictive value of sire hormone data for growth rate of progeny was also evaluated. Bulls of the index line were heavier at birth (P less than .02) and had higher postweaning daily gains (P less than .01) than bulls of the control line. Blood samples were collected from bulls (ages 2 and 3 yr) at 15-min intervals for 8 h. Overall plasma GH concentrations were higher (P less than .03) in the index bulls than those in the control line. All characteristics of PRL secretion examined tended to be higher in the index bulls, but only mean overall and baseline differences approached significance (P less than .10). There were no significant differences in measures of TSH secretion between lines. Sire differences in hormone characteristics accounted for significant amounts of variation in birth weight and postweaning gain of progeny, but not in gain to weaning. Also, when considered jointly, hormone characteristics generally added significantly to predictions that used sire growth rate alone. The results suggest that serum hormone characteristics in parents may provide additional predictors of growth rates of progeny.     

Between- and within-breed genetic analysis of calving traits and survival to weaning in beef cattle

Data for gestation length, birth weight, calving difficulty (percent assisted) and survival from birth to weaning were analyzed from 4,639 calves by 290 sires of 14 Bos taurus breeds (Hereford, Angus, Jersey, South Devon, Limousin, Simmental, Charolais, Red Poll, Brown Swiss, Gelbvieh, Maine Anjou, Chianina, Pinzgauer and Tarentaise) mated to Hereford and Angus cows. The calves were produced over a 7-yr period in a germ plasm evaluation program. Variance components were estimated for breed of sire (sigma 2b), sire within breed of sire (sigma 2s) and progeny within sire (sigma 2w) random effects. Estimates of sigma 2b and sigma 2s direct genetic variance were similar for gestation length and calf survival. Estimates of sigma 2b genetic variance were greater than for sigma 2s for birth weight and calving difficulty. Estimates of total heritability [h2t = 4(sigma 2b + sigma 2s)/(4 sigma 2b + sigma 2s + sigma 2w)] and within-breed heritability (h2w = 4 sigma 2s/sigma 2s + sigma 2w) indicated that gestation length (h2t = .77, h2w = 64) and birth weight (h2t = .79, h2w = .46) are under a high degree of direct genetic control, calving difficulty (h2t = .42, h2w = .21) is under a moderate degree of direct genetic control and calf survival (h2t = .11, h2w = .07) is under a low degree of direct genetic control. Estimates of genetic correlation for between (rb) - and within-breed (rg) sources of genetic variation were comparable in direction, but tended to be stronger between than within breeds.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maternal heterosis and grandmaternal effects in beef cattle: postweaning growth and carcass traits

Crossbred steer and heifer progeny from 5-, 6- and 7-yr-old dams produced in a four-breed diallel crossing experiment involving the Brown Swiss, Red Poll, Hereford and Angus maternal grandsires and maternal granddams were evaluated for postweaning growth and carcass traits to estimate breed mean maternal heterosis, maternal heterosis for specific breed cross females, average maternal heterosis for all crosses, breed grandmaternal effects and net breed effects in crosses. All progeny evaluated were born in 1979 and 1980 and were sired by 7/8 or 15/16 Simmental bulls. Average maternal heterosis was significant for 200-d weight in heifers but not in steers and was not significant for final weight (444-d) in either heifers or steers. The effects of maternal heterosis on postweaning growth were not important. Differences among breeds in mean maternal heterosis values were small for growth-related traits. Breeds did not differ (P greater than .05) in grandmaternal effects for growth-related traits; Brown Swiss tended to be highest, Red Poll lowest, with Hereford and Angus intermediate. Differences in net breed effects in crosses favored Brown Swiss over the three other breeds and were generally significant for growth traits. Average maternal heterosis, though generally positive, was not significant for carcass traits on either an age-constant or weight-constant basis. Differences among breeds were small in grandmaternal effects, specific heterosis and net effects in crosses for carcass traits associated with both weight or composition; generally the Brown Swiss breed was favored on carcass traits associated with weight in the age-constant analysis and generally had a higher lean-to-fat ratio than the three other breeds in both the age-constant and weight-constant analyses.     

Behaviour of commercial systemic fungicides in conventional (non-systemic) tests

Biological screens specifically designed to detect systemic fungicides, besides being slow, labour-intensive, wasteful of chemicals and very expensive, may be expected to bias the results in favour of types of activity already encountered. Evidence is presented to show that simple, non-systemic tests are efficient in selecting active chemicals with systemic properties.