Detecting tail biters by monitoring pig screams in weaning pigs.

Early identification of tail biting and intervention are necessary to reduce tail lesions and their impact on animal health and welfare. Removal of biters has become an effective intervention strategy, but finding them can be difficult and time-consuming. The aim of this study was to investigate whether tail biting and, in particular, individual biters could be identified by detecting pig screams in audio recordings. The study included 288 undocked weaner pigs housed in six pens in two batches. Once a tail biter (n = 7) was identified by visual inspection in the stable and removed by the farm staff, the previous days of video and audio recordings were analyzed for pig screams (sudden increase in loudness with frequencies above 1 kHz) and tail biting events until no biting before the removal was observed anymore. In total, 2893 screams were detected in four pens where tail biting occurred. Of these screams, 52.9% were caused by tail biting in the observed pen, 25.6% originated from other pens, 8.8% were not assignable, and 12.7% occurred due to other reasons. In case of a tail biting event, screams were assigned individually to biter and victim pigs. Based on the audio analysis, biters were identified between one and nine days prior to their removal from the pen after visual inspection. Screams were detected earlier than the increase in hanging tails and could therefore be favored as an early warning indicator. Analyzing animal vocalization has potential for monitoring and early detection of tail biting events. In combination with individual marks and automatic analysis algorithms, biters could be identified and tail biting efficiently reduced. In this way, biters can be removed earlier to increase animal health and welfare.

Effects of age, parity, and pregnancy abnormalities on foal birth weight and uterine blood flow in the mare.

Color Doppler sonography has become routine for the evaluation of high-risk pregnancies in human medicine. Previous studies documenting uterine blood flow parameters in the pregnant mare have found a decrease in peripheral blood flow resistance in the first pregnancy weeks and an increase in uterine blood flow, especially in the last trimester of pregnancy. However, these studies involved only a small number of mares. No naturally occurring pregnancy abnormalities occurred that would allow blood flow changes to be retrospectively examined and analyzed. The objective of the present study was to monitor the diameter of the uterine artery, uterine blood flow, and the combined thickness of the uterus and placenta (CTUP) throughout gestation in a large number of pregnant mares of different age and parity. In the present study, 51 warmblood mares were examined by ultrasonography on Days 16 and 30, at monthly intervals until Day 300, and then every 10 days from Day 300 until parturition. After localization of the uterine artery ipsilateral and contralateral to the conceptus, the diameter of each artery, the uterine blood flow (pulsatility index [PI], blood flow volume [BFV], and the presence of early diastolic notch), and the CTUP were measured and correlated to placental and foal birth weight after delivery. Furthermore, the effect of age (3-7 years [n = 16], 8-11 years [n = 17], 12-16 years [n = 18]) and parity (0-2 foals [n = 22], 3-4 foals [n = 15], 5-8 foals [n = 14]) on these parameters were analyzed. The diameter of the uterine artery increased more than threefold in the ipsilateral artery (0.40 ± 0.07-1.33 ± 0.08 cm) and 2.7-fold in the contralateral artery (0.39 ± 0.07-1.07 ± 0.08 cm [P < 0.0001]). The early diastolic notch disappeared in the pulse waves in 98% of the ipsilateral arteries and 85.7% in the contralateral arteries on Day 150 when placentation is complete. Blood flow volume increased 50-fold in the ipsilateral artery during pregnancy and increased dramatically in the last trimester. The median foal weight was 52.6 kg. Mares with heavier foals (>52.6 kg) had a 1.38-fold higher BFV in the last 2 months (P < 0.05) compared with lighter foals. Pulsatility index decreased 2-fold until completion of placentation at around Day 150 and continued to decline until Day 240 where it then stayed constant and at a low level until delivery. Age predominantly influenced PI, whereas the diameter of the uterine arteries, which is correlated to BFV (r ipsilateral = 0.919, P < 0.0001 and r contralateral = 0.909, P < 0.000), was strongly affected by parity. Four mares spontaneously aborted (Days 200, 208, 213, and 246) and four mares spontaneously developed placentitis that was diagnosed by the presence of an increased CTUP and/or placental pathology after delivery. Although not statistically relevant, the aborting mares showed a slightly increased total BFV, but no differences in PI were seen compared with mares without abnormalities of pregnancy. Mares that developed placentitis had a late (Days 150-210) disappearance of the early diastolic notch and an increased PI in the first half of pregnancy. In conclusion, the study documented differences in uterine artery diameter and blood flow in a large number of pregnant mares. Furthermore, this is the first known report to document uteroplacental blood flow changes associated with naturally occurring placentitis and abortion in mares.