Correction: Assessment of heat stress in 7-week old dairy calves with non-invasive physiological parameters in different thermal environments.

[This corrects the article DOI: 10.1371/journal.pone.0200622.].

Assessment of equine alpha-fetoprotein levels in mares and newborn foals in the periparturient period.

Alpha-fetoprotein (AFP) is best known in human obstetrics for its association with fetal anomalies recognized in the 1970s. Although this fetal protein had been shown to be present in the sera of many mammalian species, its possible diagnostic role in the detection of abnormalities was evaluated only later, when a research laboratory published variable levels of AFP in different groups of mares with pregnancy problems (twins, conception failure, placentitis, embryonic loss), and subsequently differences were demonstrated in its serum levels between aborted and healthy mares. In this study, peri- and intrapartal AFP levels were measured in maternal serum, amniotic fluid, neonatal blood, and umbilical blood samples. The mean levels of AFP were lower in umbilical blood and amniotic fluid samples than in foal and maternal blood. Older mares had lower AFP levels correlated with their age in years. The time remaining until foaling had a significant, non-linear effect on AFP levels: an elevation could be detected in the last two weeks of pregnancy, followed by a decline after foaling. Also, AFP levels were found to be elevated in the hot summer months. There was a significant individual variation in AFP levels in the population studied.

Assessment of heat stress in 7-week old dairy calves with non-invasive physiological parameters in different thermal environments.

We estimated thermal stress in 7-week old Holstein bull calves during a warm episode in summer to study acute physiological responses of calves to heat stress. Data were collected over a 5-day period: day 1 (control), day 2 (heat stress), and a 3-day post-stress period in shaded (n = 8) and unshaded (n = 8) thermal environments. On the control day, both groups were shaded. Thermal environment was characterized by relative humidity, ambient temperature, and the temperature-humidity index (THI). Physiological variables included respiratory rate, rectal temperature, ear skin temperature and heart rate. Correlations between animal-based and meteorological indices were calculated, and ambient temperature correlated slightly better with physiological measures than THI. Rectal temperature was the only animal-based parameter that showed stronger correlations with the thermal indices when calculated for the shaded than for the unshaded environment [r = 0.42 vs. r = 0.47, P = 0.032 (ambient temperature), r = -0.39 vs. r = -0.45, P = 0.012 P = 0.015 (relative humidity), r = 0.41 vs. r = 0.46, P = 0.022 (THI)]. No differences were found between groups during the control day for any of the physiological parameters. During days 2 and 3, average and maximal values of respiratory and heart rates were higher in unshaded calves than in shaded ones. Maximal respiratory rates were in average by 25.9, 17.8 and 10.1 breaths/min lower in shaded calves than in unshaded calves for days 2, 3 and 4, respectively (P < 0.001, P < 0.001 and P = 0.024). Maximal heart rate was 127.4 ± 8.5 vs. 99.2 ± 6.3 beats/min on the heat stress day (P < 0.001), and 121.0 ± 6.9 vs. 103.4 ± 7.7 beats/min on day 3 (P = 0.006) in unshaded and shaded calves, respectively. Maximal body temperatures were higher measured either in the rectum or on the ear skin in unshaded calves than in shaded ones (with 0.5 and 1.6°C, P = 0.040 and P = 0.018, respectively), but only on the heat stress day. Based on our results, shading of young calves may be adequate for alleviating acute heat stress in continental regions. Ambient temperature is appropriate to estimate acute heat stress in dairy calves.

Assessment of the mineral density and mineral content of the equine third metacarpal and first phalanx bone by dual energy x-ray absorptiometry.

In the first part of this methodological study eleven metacarpi of 9 skeletally normal horses were examined from 4 directions by dual energy x-ray absorptiometry (DXA). The differences between the dorsopalmar-palmarodorsal and lateromedial-mediolateral (opposite sites) bone mineral density (BMD) values were found to be nonsignificant. In the second part of the study the precision of the Norland XR-26 densitometer was tested by measuring 34 metacarpal bones and 34 proximal phalanges, each of them three times, from a single direction. The difference between the individual measurements of the first phalanges and of the metacarpal bones originating from the right or the left side of the same horse were not significant, nor did the age or breed have a significant effect on BMD or bone mineral content (BMC). However, both BMD and BMC are greater in the metacarpal bones than in the proximal phalanges and are higher in geldings than in mares or to stallions, while the BMD or BMC values of mares and stallions did not differ from each other significantly. These data point to the necessity of further BMD studies in a higher number of patients.

Radiographic assessment of pulmonary fluid clearance in healthy neonatal foals.

We characterized the kinetics of postnatal equine lung using sequential thoracic radiography. The aim was to establish the earliest time when normal foals have clear, radiolucent lung fields, and to characterize the pattern of this clearance. Both right-to-left and left-to-right thoracic radiographs were acquired in lateral recumbency at peak inspiration within the first 30 min after birth and thereafter at 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 h. Radiographs were interpreted by three observers. The overall assessment of radiographic lung clearance was followed by the evaluation of individual lung quadrants to document changes in pulmonary radiographic patterns over time. We concluded that thoracic images in a healthy foal older than 4 h should be characterized by clear lungfields and that after this time distinctions between physiologic and pathologic conditions can be made. The ventral lung cleared first, presumably due to the greater flexibility of the thoracic wall in this anatomic region.

Risk assessment of postpartum uterine disease and consequences of puerperal metritis for subsequent metabolic status, reproduction and milk yield in dairy cows.

The objective of this study was to determine some metabolic and other factors predicting the risk of postpartum uterine disease (PUD), and the effects of puerperal metritis (PM) on metabolic status, reproduction and milk yield were analysed. A total of 105 Holstein-Friesian cows were included, and sampled on day < -14 prepartum and days 4, 10-14, 28-35 and 56-63 postpartum for metabolic tests. From day 4 the development of PUD, and from days 28-35 the ovarian activity was monitored. When grade > or = 1 + ketonuria was present on day 4 postpartum, this indicated a higher probability of PUD [odds ratio (OR) 2.64; P < 0.05] including PM occurring on days 10-14 (OR: 2.65; P < 0.05). Plasma nonesterified fatty acid (NEFA) concentrations > 0.200 mmol/l on days < -14 prepartum indicated a higher risk of uterine diseases (OR: 3.44; P < 0.05). The odds of PUD increased, depending on whether a body condition score (BCS) loss of > or = 1.0 occurred between days < -14 and 28-35 (OR: 2.82; P < 0.05), between days < -14 and 10-14 (OR: 4.79; P < 0.01) or between days 10-14 and 28-35 (OR: 10.81; P < 0.01). PM was more probable (OR: 27.3; P < 0.001) in cows with retained placenta. The risk of uterine diseases was lower in multiparous than in primiparous cows (OR: 0.29; P < 0.01). PM increased the risk of ovarian inactivity between days 28 and 35 (OR: 2.83; P < 0.05). Cows affected with PM (PM+ cows) showed lower milk production on day 4 (kg; P < 0.05) and lower milk production (P < 0.05), milk fat and milk protein production (kg; P < 0.01; P < 0.01) in the first 100 days of lactation than did PM-cows.