MORPHOLOGIC FEATURES OF PEROSOMUS ("SHORT SPINE") IN FARMED SALMON (SALMO SALAR)

This study was done to characterize morphologically the spinal changes in stunted salmon, 1.5–2 years of age, spontaneously appearing in a Swedish fish farm. Radiographic examination and alizarin-alcian blue preparations showed compressed areas of the spine, most often near the dorsal fin. Of the average 50–52 vertebrae, 20–30 were often compressed, resulting in an average shortening of the fish by 23%. The histopathologic character of the shortened spine was a replacement of the chorda (intervertebral pad or disc) with a poorly differentiated hyaline cartilage, in which proliferative and degenerative processes produced a very irregular pattern. The origin of this cartilage, which had severely impaired ossifying capacity, was perichordal and it often had direct connections with the growth centers of the vertebrae. The disappearance of the large strongly convex (spheric) chorda and the arrest of the vertebral endochondral ossification resulted in narrow disc-like vertebrae in contrast to the normal X-shaped ones. The pathologic changes resemble those observed in chondrodystrophic types of perosomus ("short spine") in certain mammals, including humans, and in turkeys.     

Calf survival and reproductive performance of Holstein–Friesian cows in central Ethiopia

This study was carried out to evaluate the reproductive performance and calves survival rate of Holstein–Friesian (HF) herd in Holeta, central highland of Ethiopia. A retrospective analysis of 26 years data was carried out, from which records of 724 age at first calving (AFC), 2,022 calving intervals (CI), 2,971 breeding efficiencies (BE), 260 abortions, 111 stillbirths were derived from 795 cows. Moreover, 738 female calves’ records were also included for survival rate study. The overall least squares means of AFC, CI, and BE were 40.9 ± 0.33 months, 475 ± 2.84 days, 81.9 ± 0.26%, respectively, while the incidence rates of abortion, stillbirth, and female calves survival rate for this herd were 8.0%, 3.4%, and 77.5%, respectively. The effects of parity number and year of birth/calving on CI and BE were significant (P < 0.001). Moreover, birth year had significant (P < 0.001) effect on AFC and calves survival rate, while calving season had significant effect on BE. The reproductive performance found in this study was lower than the performance reported in many tropical regions and the genetic potential of HF breed in their origins. Moreover, higher loss due to calf mortality was observed. Thus, the centre should consider appropriate measures to improve its herd reproductive performance and calves survival rate for attaining its aspired objectives.