[Control of puerperium in swine under conditions of extremely shortened nursing method. 1. Results of histological studies in postpartum involution and regeneration of the uterus under conditions of extremely shortened nursing period and medicamentous control of puerperium]. / Zur Steuerung des Puerperiums beim Schwein unter der Bedingung extrem verkürzter Säugezeit. 1. Mitteilung: Ergebnisse histologischer Untersuchungen zur postpartalen Involution und Regeneration des Uterus bei extrem verkürzter Säugezeit und medikamenteller Beeinflussung des Puerperalverlaufs.

Uterus tissue samples were taken from 31 sows which had been under regimes of extremely shortened nursing periods and differentiated medication to control their puerperium. The samples were taken following laparotomy during the first postpartum oestrus as well as in subsequent phases of the cycle and histologically tested for puerperal involution and regeneration. The endometrium and myometrium of sows in oestrus were found to be in a condition which widely corresponded to normal oestrus condition of the uterus wall, when their piglets had been weaned in the third postpartum week. However, untreated sows in oestrus, whose piglets had been weaned extremely soon, that is in the second postpartum week, displayed numerous signs of inadequate postpartum involution and regeneration. Oxytocin was found to work well in speeding up regeneration of both the endometrium and myometrium. Intramuscular injection of twice nine International Units per die, from the first through ninth days postpartum, helped to complete largely all regeneration processes up to the first oestrus, when piglets had been weaned in the second postpartum week. Oral antibiotic medication (chlortetracycline) and parenteral application of vitamins failed to produce any substantive and histologically recordable effect on puerperal involution processes.

[Studies on improving the fertility of aged sows. 3. Results of histological studies on puerperal involution and regeneration processes in the endometrium of lactating sows and sows after extremely early weaning]. / Untersuchungen zur Steigerung der Fruchtbarkeitsleistung bei Altsauen 3. Mitt.: Ergebnisse histologischer Untersuchungen über die puerperalen Involutions- und Regenerationsvorgänge am Emdometrium von säugenden Sauen und Sauen nach extrem frühem Absetzen der Ferkel

Involution and regeneration following parturition was studied in 48 sows allowed to suckle their piglets normally, or from which the piglets were taken away at 5-8 days of age. Samples of uterus were obtained by biopsy 4, 8, 11, 14, 17, 20, 30, 32 and 40 days after parturition. In lactating sows, endometrial changes similar to those of oestrus in a normal cycle were present 32 days after parturition. This fact seems to justify the removal of piglets at 21-28 days of age. After very early weaning (5-8 days), incomplete oestrus-like changes in the endometrium were seen on the 17th day after parturition. The observed involutionary and regenerative changes in the puerperal uterus suggest that early weaning after 10-12 days of suckling is feasible, but it may be advisable to use drugs that would accelerate uterine involution.