Recovery of consciousness in hogs stunned with CO2: physiological responses.

The objective of the present study was to determine the impact of recovering consciousness on physiological responses in hogs stunned with different concentrations of CO2. A total of 1336 pigs were moved into a CO2 anaesthesia chamber for 90s. The remaining pigs were assigned to 3 groups according to the CO2 concentration used for stunning: 85, 90 or 95%. Each group was then further divided into 2 sub-groups: those exsanguinated during the first 60s after leaving the chamber without recovering consciousness (WRC); and those exsanguinated after more than 60s that recovered consciousness (RC). The blood pH of the RC pigs decreased below 7.08, but their blood levels of Ca(2+) (>1.59mmol/L), glucose (>159.79mg/dL), and lactate (>103.52mg/dL) all increased when compared to reference values (RV) (P<0.05). Therefore, a greater metabolic and energy imbalance occurs during exsanguination when pigs recover consciousness. In conclusion, exsanguination should be performed immediately upon the pigs leaving the CO2 chamber.

Vetrabutine clorhydrate use in dystocic farrowings minimizes hemodynamic sequels in piglets.

The objective was to measure the effects of VC (a uterotonic drug with vasodilator effects) in eutocic and dystocic sows, on the acid-base balance and some vitality traits of piglets at birth. Farrowing was induced with prostaglandin F2α. Four groups of sows (20 sows/group) were monitored; Groups 1 and 2 were eutocic sows, whereas Groups 3 and 4 were dam-fetal dystocic sows. Groups 1 and 3 (control) were given saline, whereas Groups 2 and 4 were given VC im (1.66 mg/kg of body weight) after the first piglet was born. Piglets' physio-metabolic performance was monitored peripartum. Treatment with VC reduced (P<0.0001) the percentage of intrapartum stillbirths in sows either with eutocic (5.2 vs. 10.0%) and dystocic (7.6 vs. 16.7%) farrowings and increased (P<0.0001) the number of pigs born alive without any evidence of AFS (89.9 vs. 79.9%, eutocic and 81.6 vs. 65.2%, dystocic). In addition, for the group of pigs with no acute fetal suffering (AFS), VC treatment enhanced survival responses with a half point grater vitality score in Group 4; it also reduced the latency to first teat contact by 6 min (P<0.05) in both treated groups compared to controls; and it improved the condition of the pigs' umbilical cord, with more adhered (98 vs. 86% in eutocic and 88 vs. 80% in dystocic; P<0.05) and less ruptured cords. Moreover, VC reduced the severity of adverse physio-metabolic indicators and the acid-base balance of piglets with AFS at birth by lowering blood lactate (89.8 vs. 93.5 mmol/L in eutocic groups and 94.6 vs. 100.2 mmol/L in dystocic groups; P<0.05), PaCO2 and Ca2+, and by increasing blood pH, HCO3 and PaO2 levels (P<0.05).

Effects of long distance transportation and CO2 stunning on critical blood values in pigs.

The aim of the study was to evaluate the effect of two stressful stimuli, long transportation and 80% CO(2) stunning on metabolic-physiological variables, hemodynamic and gas exchange in slaughter pigs imported from the U.S. to Mexico City with a journey time of 27 h, with 8 h of lairage at the abattoir. A total of 589 pigs from three genders were monitored. Overall results show that both stimuli caused metabolic and physiological disturbance. Gilts were more efficient in controlling glycemia after a long transport journey (24h), than castrated males (P<0.05), whose glucose was increased above the 30 mg/dL basal level. Females on arrival had 23mg/dL more lactate compared to basal levels (P<0.05). Stunning caused more physiological effects compared to transportation. Regarding the gender factor, females and entire males were more susceptible to transport stress and stunning compared to the castrated pigs, and entire males showed more complications restoring the gas exchange compared to females and barrows.

Changes in blood constituents of swine transported for 8 or 16 h to an Abattoir.

The effects of two transportation periods on physio- metabolic hemodynamic changes and gaseous exchange in commercial swine during transportation to the slaughterhouse was studied in 684 pigs, 357 barrows and 327 gilts, transported in 2 groups for 8 and 16 h. Transportation caused an increase of oxygen consumption and body temperature, a decrease in pH, lactic acid accumulation. Both transportation periods caused higher than normal plasma glucose levels, lactic acidosis and evidence of dehydration. The linear regression analysis for pigs transported for 8h indicates that the PO(2,) lactate and Ca(++) variables correlated negatively with the PCO(2.) Whilst the animals that were transported for 16 h had negative correlations between glucose, and calcium, hematocrit, lactate and potassium levels. It was concluded that regardless of transport time acidosis, hypocapnia, hypoxaemia, hypernatraemia, hypercalcaemia, hyperglycemia, lactacidemia and increased hematocrit levels occurred.

CO(2) stunning may compromise swine welfare compared with electrical stunning.

The effects of two different stunning methods on critical blood values in fattening pigs at a federal inspection slaughtering plant were monitored. A total of 658 pigs from the same genetic line and origin, were randomly assigned to 3 treatments: reference baseline levels (resting pigs; T1), stunning with CO(2) (T2) and stunned electrically (T3). Energetic profile, acid imbalance and blood gas levels, were monitored. Significant differences (p⩽0.05) between treatments for all variables were found, CO(2) stunned pigs showed hypercapnia, hypercalcemia, hyperglucemia, lactic acidemia, and an increase in haematocrit, coupled with reduced pH, [Formula: see text] , and Na; electrically stunned pigs had reduced blood pH, [Formula: see text] and [Formula: see text] . The remaining indicators were increased in relation to the resting swine. Thus CO(2) stunning leads to a major imbalance because of mineral and acid base gaseous interchange, compared to electric stunning, thus possibly compromising animal welfare.

Short-term neurophysiologic consequences of intrapartum asphyxia in piglets born by spontaneous parturition.

Piglets appear to be neurologically sensitive to intrapartum asphyxia. Our aim was to investigate the short-term neurophysiologic consequences of intrapartum asphyxia in piglets. We studied 10 piglets suffering intrapartum asphyxia and 10 control piglets. Glucose and blood gas levels, tympanic membrane temperature, and body weight were measured within the first 2 min after birth. Animals were followed up for a 5-day period. As surrogated markers of piglets' neurological function, a viability score and the time elapsed from birth to the first contact with the maternal udder were recorded. In the control group, temperature and blood pH levels at birth were significantly higher (p < or = .001), whereas calcium, lactate and PCO2 levels were statistically lower (p < or = .05) than in the piglets experiencing intrapartum asphyxia. Lower temperature and blood pH levels as well as higher blood PCO2 and lactate levels were observed in piglets with lower viability scores and in piglets with prolonged times until first udder contact. At the end of the study, asphyxiated piglets weighed on average 200 g less (p = .023) than control piglets. In conclusion, intrapartum asphyxia in spontaneously born piglets was associated with signs of acute neurological dysfunction and lower weight gain, supporting the hypothesis that they may be used as a naturalistic model for the study of asphyxia in newborns.