Ultrasonography evaluation of ovary and uterus avoids the inclusion of not pubertal gilts in a program of oestrus synchronization with altrenogest

The administration of Altrenogest (ALT) is an effective system to synchronize oestrus gilts but it has to be utilized only in pubertal animals. Usually, it is difficult to precisely know the reproductive status of gilts and some animals may be treated with ALT even if they are not pubertal. The aim of this study has been to differentiate pubertal from not-pubertal gilts by ultrasound (US) evaluation of ovary and uterus before a program of oestrus synchronization with ALT.

In this study 210 crossbred gilts of 8 months of age were divided in two group: 108 gilts (ALT+US group) were examined by US (Honda HS-1600V, convex probe: 9.0/7.5/5.0 MHz) and diagnosed as no-pubertal or pubertal. Gilts were considered as ‘‘pubertal’’ in the presence of: i) follicles > 6 mm or/and of CLs; ii) a uterus diameter more then 1.2 cm2 that extends into the caudal abdomen iii) clearly shaped uterine loops. Gilts were considered no-pubertal: i) in absence of CLs and with follicles < 5 mm; ii) with a uterine diameter less than 1.2 cm2 that occupies only a minor space and that is located very close and cranial to the urinary bladder, iii) with the uterine loops that are closely attached to each other, appears to be partially overlapped and are not visualized as clearly separated cross-sections. Thereafter, only pubertal gits were treated with 15 mg ALT (Regumate®) for 18 days. A second group of 102 gilts (ALT-NO-US group) were not evaluated with ultrasound but directly treated with ALT.

In ALT+US group 18/108 (16%) gilts were considered as not-pubertal and excluded from the treatment with ALT. The remains 90 gilts were synchronized and 82 (91%) went in oestrus and 72 (94%) become pregnant. In ALT-NO-US group, 89/102 (87%) gilts after ALT treatment were in oestrus and 77 (86%) become pregnant.

The results of this study confirm previous data from literature that ultrasonography of ovary and uterus is an appropriate method to distinguish between not-pubertal and pubertal gilts and avoids the inclusion of not pubertal gilts in a program of oestrus synchronization with altrenogest.

Disclosure of Interest: None Declared