Cas clinique : anomalies morphologiques de la semence de verrat associées à un excès de zinc dans l'aliment

In a teaching herd of Piétrain pigs, three boars aged 18 (A), 15 (B) and 9 (C) months showed morphological abnormalities of sperm. Sampled once a week since mid-September 2024, boars A and B showed an increasing rate of flagellar abnormalities from early October: tails bent between the mid- and the main piece or even coiled tails. Boar C, which was first trained for semen production at the end of November, immediately presented abnormal semen. The normal spermatozoa rate of boar A decreased from 84% to 16% from 30 September to 3 December 2024. On the latter date, the normal spermatozoa rate, semen mobility and motility were respectively 16%, 30% and 2 (boar A), 0%, 10% and 1 (boar B) and 0%, 5% and 2 (C). On 3 December 2024, boar C's ejaculate was
haemorrhagic, which suggested urolithiasis. On that date as well, the boars' feed was modified, and blood samples were taken to measure zinc levels (boars A-B). Feed was also analysed. The blood zinc concentration of boars A and B was 148 and 194 µg/dL, respectively (normal range: 65-131 µg/dL). Analysis of the feed revealed an excess of zinc, but also of manganese, copper, iodine, cobalt and selenium. In boars, abnormal sperm motility/morphology is attributed mainly to iatrogenic (vaccination), infectious, environmental (heat stress), traumatic or genetic causes, but nutritional imbalances should also be included in the differential diagnosis.