REFERENCE :  Mee JF, Buckley F, Ryan D, Dillon P. Pre-breeding ovaro-uterine ultrasonography and its relationship with first service pregnancy rate in seasonal-calving dairy herds. Reprod.Dom.Anim,2009,44,331-337.

INTRODUCTION

Early identification of postpartum problem cows by monitoring uterine involution is an integral part of reproductive monitoring. The prognosis of these animals is most often done by manual palpation of the genital tract, vaginoscopy and more rarely by biopsy, endometrial cytology or progesterone measurement in blood or milk.

For many years, ultrasound has been used more and more intensively in bovine reproduction, especially when applied to the early diagnosis of pregnancy.  The aim of this study is to (1) characterize an ultrasound score of the reproductive tract (SETG: URTS Ultrasound Reproductive Tract Scoring), (2) to specify its distribution in Irish dairy farms and (3) to demonstrate its interest on the prognosis of fertility of the animals concerned.

MATERIALS AND METHODS

The study included 7797 ultrasound examinations performed on 5751 Holstein dairy cows in 62 herds with an average of 87 cows producing 6557 kg of milk in 305 days. The ultrasound examination (5 MHz probe) concerns animals more than 14 days into lactation. The herds are visited at intervals of 40 to 50 days.

The determination of the score is based on the characteristics of the ultrasound image of a cross-section of a uterine horn and on the presence or absence of a corpus luteum (CL).

RESULTS AND DISCUSSION

The main characteristics of the animals examined are presented in the table below.

The majority of the examined cows (88.6%) had a corpus luteum at the time of their first examination performed on average 57 days after calving. This percentage of anoestrus is relatively lower than that found in other studies (15-38%). 3.9% of cows had an ovarian cyst.

The nature of the score obtained depends closely on the time of the interval between calving and the first examination.

Scores 1 and 6 were significantly later than the others.

Score 2 could reflect delayed uterine involution or mild endometritis (subclinical endometritis which ideally requires cytological analysis of uterine contents to identify).

Scores 3 and 4 indicate chronic endometritis or delayed uterine involution. Score 5 identifies a pyometra. The percentages reported (2.2, 3.3 and 2.2%) are lower than those usually described.

Compared to cows with an ultrasound score of 1, cows with a score of 2 to 6 were significantly less likely to be pregnant at the first insemination performed 16 to 29 days later. This negative relationship between delayed uterine involution and chronic, subclinical or pyometral endometritis is unanimously accepted.