Abstract. Two Holstein calves affected with cerv ico-pecto ral ectopia cord is, a male (No. 1)delivered stillborn and a female (No .2) died I hou r after birth, were examined macroscopically and radiographically to assess the sever ity and elucida te the teratogenesis of the anomaly. T he heart of one calf was cove red by the intact pericardi um and skin and d isplaced to the cauda lmost porti on of the ventrocervical region , j ust cranial to an enlarged thoracic inlet. T he cranial vena cava and the vena azygos were dupli cated. The sternum was bilaterally divided into two part s fused only at the xyphoid process and was semicircular. The heart of the other calf, cove red solely by the pericardiu m, was exposed ventrally from an oval openin g in the body wall j ust cranial to a defective Y-shaped stern um. In both calves, the arterial branching patt ern from the aorti c arch was interm ediate between the patt erns of the dog and pig, and in each case a single pulmonary vein emptied into the left atrium . Pronounced or slight torticollis, cleft palate, and abnormalities in the urogenital system were also found . From an embryological perspect ive, cerv ical and pectoral ectopia cordis have a common path ogenesis; the cervical type occurs at a slightly earlier fetal stage than the pectora l type.Key words: Catt le; congenital malforma tion ; ectopia cordis ; pathogenesis. ResultsCalf No. I nums were radiographed with soft x rays (Softex K-2, Softex Co., Tok yo, Japan). Materials and MethodsEcto p ia co rdis (EC), a co nd itio n d efin ed as th e a bno rm al po sition of th e heart a n yw he re o utsi de th e th oracic cavi ty , is su bdivided into th ree typ es accordi ng to th e si te o f di spl acement: ce rvical, pect oral , a nd a bd om in al. In ca tt le , the ce rvica l typ e is th e m ost pre va lent. 3.8.1 0.1I A rare in termed ia te typ e o f EC , partiall y cerv ica l a nd partiall y pect oral , has been d ocumented in on ly o ne bo vine case .v Two exa m ples o f th e intermediate typ e we re prese nte d a t o ur laborato ry recentl y. N ecropsy o f tw o neonatal ca lves re vealed EC characte rized by th e reloc ati on o f th e heart between th e ce rv ica l region and th e pect oral regio n. T o eluc idate possibl e e m bry o logica l impli cations in th e teratogen esis o fEC, the gr o ss anato my o f th ese animal s wa s co m pa red with that of th e ca lves wi t h th e ot he r typ es of EC d efect s.This ca lf was co m p lete ly d e veloped a nd weighed 50 kg (us ua l size for a m ale neonate Hol st ein) . The ski n was intact , a nd th e hair coat was normal. H ow e ver, pronounced torticolli s to th e right wa s ev iden t, and a swe lli ng wa s apparent in th e ca ud alm o st cervi cal regio n just a few ce n timete rs cra n ia l to the enlarged th oracic inl et (Fig. I) .The left a nd right ste rnocep ha lic muscles , originatin g bil aterall y from th e ste rn u m , fused wit h th e braehi oceph ali c muscles. The fused pairs o f muscles were thin a nd fatty a nd cra n ia lly di verged at th e...

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Summary. Microvascular changes during the development of follicles in bovine ovaries were studied by scanning electron microscopy of corrosion casts. A clear vascular plexus of ovarian follicles appeared at the stage when secondary follicles were 200-400um in diameter. The plexus consisted initially of a thin, roughly structured and single-layered capillary network.During follicular development, the microvascular architecture of antral follicles was arranged as two independent vascular plexuses. The inner plexus, which received a spiral arteriole, consisted of a dense sinusoidal capillary network with an arterial and a venous layer; it functioned as an independent microcirculatory unit. The inner plexus developed from the capillary plexus of the theca interna of the secondary follicles. The outer plexus, which anastomosed with several stromal capillaries, consisted of a thin, coarse and basket-like capillary plexus. The outer plexus was formed from the stromal capillary plexus as a consequence of the rapid enlargement of developing antral follicles.

The present study demonstrated the microvasculature of bovine mature follicles and microvascular changes with ovulation. The microvasculature of bovine mature follicles consisted of 2 capillary plexuses, the inner and outer. The inner capillary plexus consisted of a thick, dense sinusoidal capillary layer and a rough layer of arterioles and venules. Their plexus was characterized as an independent microcircular unit receiving only one afferent vessel. Microvascular changes with ovulation appeared in the inner capillary plexus. In preovulatory follicles, inner sinusoidal capillaries gave rise to topographical increases in permeability. These phenomena may play an important role in causing the radical increase of follicular fluid pressure and cumulus oophorus discharge. In postovulatory follicles, the inner capillary plexus protruded into the follicular antrum and underwent remarkable angiogenesis to rapidly form the blood vascular bed of the corpus luteum.