Calving duration and obstetric assistance influence pulmonary function of Holstein calves during immediate fetal-to-neonatal transition

Abstract

Neonatal immediate adaptation to extrauterine life depends mainly on adequate lung function, which is under the influence of previous fetal maturation and obstetrical condition, both acting to stimulate the efficient liquid removal from the pulmonary parenchyma during the immediate transition period. The objective of the present study is to identify chest radiographic changes of neonatal calves born under the influence of different duration of calving and obstetric assistance and correlate with clinical analysis and blood acid-base balance. Experimental groups were determined according to the duration of calving: 2 h (n = 16), 2–4 h (n = 16) and >4 h (n = 12), and additionally by two sub-groups: no-intervention calving (n = 22) and intervention calving (n = 22). Neonatal calves were evaluated for heart and respiratory rate at birth, 5 min, every 10 min until 90 min. Arterial acid-base balance was determined immediately after calving and thoracic radiographs were made at 10 min of life. Lung radiopacity was higher in the 2–4 hr Group compared to the 2 hr Group. When calving duration was greater than 4 hours, a significant respiratory depression was observed. Calving greater than 2 hours slower neonatal pulmonary clearance, 100% and 91.6% of the calves born in the 2–4 hr and >4 hr Groups, respectively, had mild to moderate lung parenchyma opacity. There was a positive correlation between lung radiographic changes and blood TCO2 and negative correlation between pulmonary opacity score and blood PaO2 and SO2. Hence, it is possible to infer that neonatal hypoxia during prolonged calving has an imperative influence on pulmonary fluid absorption in calves. In conclusion, calving greater than 2 hours impacts pulmonary function at birth, leading to altered lung gas exchange, pulmonary clearance, cardiac and respiratory pattern. Conversely, obstetric intervention when calving has duration greater than 4 hours is beneficial for neonatal oxygenation.

Oxidative stress and acid–base balance during the transition period of neonatal Holstein calves submitted to different calving times and obstetric assistance

“…As described in detail previously, using the same study population (Vannucchi et al, 2017(Vannucchi et al, , 2018, we conducted a prospective and observational study in a single dairy herd with high-milk-producing Holstein cows and heifers of BCS between 2.5 and 3.5. The local air temperature and humidity ranged from 17.6 to 23.5°C and from 68.3 to 79.7%, respectively, with an average wind speed ranging from 9 to 11 km/h.…”

Duration of calving stages in beef cows under different housing systems

“…Longer duration of calving birth increases the risk of maternal and fetal complications and mortality of the newborns. Adaptation of calves to postnatal life depends mainly on lung function, which is affected by fetal development, that stimulates effective removal of fluid from their parenchyma during the transition period (Vannucchi et al 2018).…”

Changes of Acid-Base Variables in Dairy Cows with Chronically Implanted Fetal and Maternal Catheters during Late Gestation and Calving

“…A close correlation could be found between the duration of the second stage of calving and the duration of obstetrical assistance because the prevalence of severely acidotic calves (pH < 7.0) can be increased if the duration of the second stage of calving is extended (<2 h: 0%, 2 to 4 h: 19%, 4 to 7 h: 44%: [ 15 ]). In contrast, besides respiratory acidosis, Vannouchi et al [ 34 ] reported normal mean metabolic parameters (BE: −5.4 mmol/L, HCO 3 − : 20.5 mmol/L, TCO 2 : 21.9 mmol/L) even if the duration of calving was longer than >4 h. At the same time, a significant respiratory depression (altered lung gas exchange and delayed lung clearance) was also observed [ 43 ]. Therefore, it is important to emphasize for the dairy practice that, in agreement with Comline and Siver [ 22 ], not only the pH value and the blood gases but the other acid-base variables will start to move in the direction of expressed respiratory and metabolic acidosis only after appearing the amniotic sac and fetal feet in the vulva during the second stage of labor.…”