Twelve bulls carrying the 1/29 chromosome translocation were compared with 45 chromosomally normal bulls concerning sexual functions, semen characteristics, and fertility. All bulls were unselected from the point of view of fertility. Sexual functions such as libido and serving ability were found to be quite normal in bulls carrying the 1/29 chromosome translocation. The semen analysis indicated small reductions in the concentration of semen and in the total number of spermatozoa but the volume of the ejaculate as well as qualitative characteristics of the semen such as wave motion and motility appeared normal. The fertility was reduced and the non‐return rates to service at 28 and 56 days pointed to a reduction of 5 and 7%, respectively, expressed as percentage of the mean rates of the association.

Puerperal paresis in dairy cows has been and still is the subject of intensive research. Investigations are mainly concerned with the clinical picture, aetiology and pathogenesis of the disease. Only in a few instances does the material permit a statistical study of variations in the manifestation of the disease and the cause of such variations. A few investigations of this kind do exist however. JONSSON (1960) studied the influence of year, age, season, production capacity and other factors on the incidence of puerperal paresis in a fairly large population of Swedish cattle. GANTING (1964) reported statistical data from a population of insured cows. EKESBO (1966) and NURMIO (1968) investigated a possible breed variation. EKESBO found a clear-cut variation in incidence between Swedish breeds, whereas NURMIO could not show any difference between Finnish Ayrshire and Finnish Landrace cows. Breed difference is a manifestation of the genotype if the breeds compared have similar environments. As far as we know the present investigation is the first aimed directly at testing genetic predisposition. A preliminary report was published earlier (DYRENDAHL et al., 1970).The primary object of the present investigation was to elucidate the genetic predisposition for puerperal paresis. Since serum calcium determinations were made on all paretic cows, the variation of this parameter was also investigated. Certain additional aspects of the variation of the disease were also included.

Summary Data were collected from 1702 cows with retained placenta. All cows came from herds served by artificial inseminations, 72 per cent being Swedish red‐and‐white (SRB), 25 per cent Swedish Friesian (SLB) and 3 per cent other breeds. The incidence of retained placenta was higher after twin births and when the calves were stillborn. The sex distribution of the calves was normal. A positive correlation existed between retentio secundinarum and parturient paresis. On the other hand the incidence of ketosis did not increase after retentio secundinarum. Among pure‐bred cows the incidence of retentio secundinarum was 4.8 per cent in SRB and 7.9 per cent in SLB cows. The incidence increased markedly with age in both breeds. The risk was rather greater during the grazing than during the housed period. The gestation period was, on average, about 2 days less than in cows with normal expulsion of placenta. Retentio secundinarum had a negative effect on fertility. This was most marked in cases when the placenta was non‐removable, but the effect was significant also when the placenta was fully removable. Parenteral administration of up to 60 mg. diethylstilboestrol had per se no negative effect on fertility. In 62 per cent of the cases the placenta was fully removable. It was more difficult to remove after a short than after a normal gestation period. Abnormal vaginal discharges occurred in 62 per cent of the cows. Zusammenfassung Retentio secondinarum bei Kühen (Häufigkeit, klinische Befunde, Einfluß auf die Fruchtbarkeit) Die Befunde wurden bei 1702 Kühen erhoben, die künstlich besamt wurden. 72% der Patienten gehörten der Rasse Swedish red‐and‐white (SRB), 25% der Swedish Friesian (SLB) und 3% anderen Rassen an. Bei Zwillings‐und Totgeburten war der Prozentsatz der Retentio secundinarum (R. s.) erhöht. Auf die Geschlechtsverteilung der Kälber sowie die Ketoseinzidenz hatte die R. s. keinen Einfluß, hingegen war eine positive Korrelation zwischen der R. s. und der Paresis puerperalis festzustellen. Bei reinrassigen SRB‐Kühen betrug die R. s.‐Inzidenz 4,8%, bei SLB‐Kühen 7,9%. Mit zunehmendem Alter erhöhte sich der Prozentsatz der R. s.‐ Fälle bei beiden Rassen. Während der Weidezeit traten etwas mehr R. s.‐Fälle auf als während der Stallperiode. Bei den R. s.‐Patienten war die Trächtigkeitsdauer 2 Tage kürzer als bei den Tieren ohne R. s. Die R. s. beeinträchtigte die Fruchtbarkeit, und zwar am stärksten, wenn die Plazenta manuell nicht abgelöst werden konnte, aber auch in Fällen, bei denen die Plazenta entfernt werden konnte. Diäthylstilboestrol (60 mg parenteral) hatte keine negative Wirkung. In 62% der Fälle konnte die Plazenta ganz entfernt werden. Die Ablösung war bei den Tieren mit verkürzter Tragzeit etwas schwieriger als bei denjenigen mit normaler Graviditätsdauer. Abnormer Vaginalfluß war bei 62% der Kühe zu verzeichnen. Résumé Rétention placentaire chez des vaches (fréquence, résultats cliniques, influence sur la fertilité) Les résultats ont été obtenus à partir de 1702 vaches inséminées artificiellement. Le...