Thermographic variation of the udder of dairy ewes in early lactation and following an Escherichia coli endotoxin intramammary challenge in late lactation

Abstract

A total of 83 lactating dairy ewes (Manchega, n=48; Lacaune, n=35) were used in 2 consecutive experiments for assessing the ability of infrared thermography (IRT) to detect intramammary infections (IMI) by measuring udder skin temperatures (UST). In experiment 1, ewes were milked twice daily and IRT pictures of the udder were taken before and after milking at 46 and 56d in milk (DIM). Milk yield was 1.46 ± 0.04 L/d, on average. Detection of IMI was done using standard bacterial culture by udder half at 15, 34, and 64 DIM. Twenty-two ewes were classified as having IMI in at least one udder half, the others being healthy (142 healthy and 24 IMI halves, respectively). Four IMI halves had clinical mastitis. No UST differences were detected by IMI and udder side, being 32.94 ± 0.04°C on average. Nevertheless, differences in UST were detected for breed (Lacaune - Manchega=0.35 ± 0.08°C), milking process moment (after - before=0.13 ± 0.11°C), and milking schedule (p.m. - a.m.=0.79 ± 0.07°C). The UST increased linearly with ambient temperature (r=0.88). In experiment 2, the UST response to an Escherichia coli O55:B5 endotoxin challenge (5 μg/udder half) was studied in 9 healthy Lacaune ewes milked once daily in late lactation (0.58 ± 0.03 L/d; 155 ± 26 DIM). Ewes were allocated into 3 balanced groups of 3 ewes to which treatments were applied by udder half after milking. Treatments were (1) control (C00, both udder halves untreated), (2) half udder treated (T10 and C01, one udder half infused with endotoxin and the other untreated, respectively), and (3) treated udder halves (T11, both udder halves infused with endotoxin). Body (vaginal) temperature and UST, milk yield, and milk composition changes were monitored by udder half at different time intervals (2 to 72 h). First local and systemic signs of IMI were observed at 4 and 6h postchallenge, respectively. For all treatments, UST increased after the challenge, peaking at 6h in T 0055 (which differed from that in C00, C01, and T10), and decreased thereafter without differences by treatment. Vaginal temperature and milk somatic cell count increased by 6h postchallenge, whereas lactose content decreased, in the endotoxin-infused udder halves. Effects of endotoxin on lactose and somatic cell count values were detectable in the infused udder halves until 72 h. In conclusion, despite the accuracy of the camera (± 0.15°C) and the moderate standard errors of the mean obtained for UST measures (± 0.05 to 0.24°C), we were unable to discriminate between healthy and infected (subclinically or clinically) udder halves in dairy ewes.

Milk yield, milk composition, and milk metabolomics of dairy goats intramammary-challenged with lipopolysaccharide under heat stress conditions

“…Compared to TN-LPS, HS-LPS had or tended to have lower milk lactose at 4 to 8 h after LPS infusion (P = 0.011 to 0.072). The decrease in lactose content in LPS challenged mammary glands was also observed in dairy ewes 33 . The drop in lactose in milk is an indicator of tight-junction leakiness 35 since lactose partially moves to blood.…”

“…The LPS challenge resulted in greater milk protein (3.72 vs. 3.08% for LPS and CON udder-halves, respectively; P < 0.01), whereas HS did not affect the milk protein (P = 0.188). Greater milk protein contents in LPS challenged mammary glands were also observed in dairy ewes 33 and cows 34 , which has been attributed to the influx of blood-borne proteins 34 . From 2 to 24 h the increment in milk protein caused by LPS injection was more marked in HS (+1.08 points) than in TN goats (+0.63 points).…”

“…The intramammary infusion of LPS in one half-udder while keeping the other half as control has been used by us and others to evaluate mammary immunity in sheep 33 and cows [25][26][27][28][29] . It mimics responses to natural mastitis but without causing a true infection 26 .…”

Investigation of body and udder skin surface temperature differentials as an early indicator of mastitis in Holstein Friesian crossbred cows using digital infrared thermography technique

“…In this study, IRT was found as a rapid and non–invasive cow-side technique for early detection of SCM in crossbred cows. Several studies demonstrated the use of IRT for early detection of SCM and clinical mastitis in dairy cows and ewes [8,11,14]. Skin temperature reflects the status of tissue metabolism, blood circulation, and abnormal thermal patterns can signify areas of superficial inflammation or circulatory impairments.…”

Changes in Udder Skin Surface Temperature of Dairy Cows Caused by Machine Milking

“…The statistical significance of these differences was not mentioned but based on reported figures, it could be determined that they were significant (P ≤ 0.05). A second study on the effect of various factors on udder SST in Manchega and Lacaune sheep (Castro-Costa et al 2014) revealed that the udder temperature measured using 55 × 40 pixel rectangles placed on both rear udder quarters significantly increased (by approx. 0.13°C) as a result of milking, which could be explained by the hyperaemia caused by the manipulation of the udder.…”