D. Mota-Rojas

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.

CO2 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.

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.

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 ≤ .001), whereas calcium, lactate and PCO2 levels were statistically lower (p ≤ .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.

Effects of administration of caffeine on metabolic variables in neonatal pigs with peripartum asphyxia

OBJECTIVE To determine effects of 2 doses of caffeine on metabolic variables in neonatal pigs with peripartum asphyxia. ANIMALS 180 neonatal pigs. PROCEDURES Neonatal pigs were assigned to 2 groups (groups P and F) on the basis of results for a vitality scale (passed or failed, respectively). Within each group, there were 3 subgroups of 30 pigs each. Within each group, the 3 subgroups received a placebo that consisted of an empty gelatin capsule, a gelatin capsule that contained 20 mg of caffeine, and a gelatin capsule that contained 35 mg of caffeine, respectively; all capsules were administered orally (0 hours). Blood samples were collected immediately before and 24 hours after capsule administration. RESULTS Pigs in groups P and F that received 20 or 35 mg of caffeine had significant increases in triglyceride concentrations. All pigs in groups P and F had a significant decrease in lactate concentrations, although the placebo-treated pigs in group F had larger decreases than did the group F pigs treated with 20 or 35 mg of caffeine. Glucose concentrations increased significantly in group F pigs treated with 20 or 35 mg of caffeine (30% and 50%, respectively), whereas glucose concentrations remained unchanged in group P pigs. In pigs treated with 35 mg of caffeine, the final weight obtained for group F was approximately 8% lower than that obtained for group P. CONCLUSIONS AND CLINICAL RELEVANCE Administering caffeine immediately after birth to neonatal pigs with severe oxygen restriction resulted in significant improvements in metabolic variables.

Influence of time at which oxytocin is administered during labor on uterine activity and perinatal death in pigs

Oxytocin is extensively used to induce or augment uterine contractions, especially to facilitate the third stage of labor in humans. Administration of oxytocin to parturient sows reduces duration of labor whereas mortality of the offspring may remain unchanged. This study aimed to evaluate whether time of administration of oxytocin during parturition may alter the uterine response and fetal outcomes. Two hundred parturient sows were randomly assigned to intramuscularly receive either saline solution (control group) or oxytocin 0.083 IU/kg immediately after the delivery of the 1st, 4th or 8th piglet (groups O-1, 0-4 and 0-8, respectively). Uterine effects and fetal outcomes were registered in all groups. The duration of labor was 20-40 min shorter (P < 0.0001) and time interval between babies was reduced by 3-5 min (P < 0.0001) in the three groups receiving oxytocin. The duration and intensity of contractions, meconium-stained piglets and intrapartum deaths decreased as time at which oxytocin administered during labor was increased. In group 0-8, we observed approximately 70% less meconium-stained piglets and intrapartum deaths than in the control group. In conclusion, oxytocin administered at early phases of parturition to sows may increase duration and intensity of uterine contractions as well as adverse fetal outcomes.

Uterine activity and fetal electronic monitoring in parturient sows treated with vetrabutin chlorhydrate.

The aims of the study were to characterize the uterine activity in sows treated with vetrabutin chlorhydrate (VC), an uterotonic and muscle-tropic drug during farrowing, and to measure the effects of the drug on piglet neonatal viability. The experiment involved 1478 piglets from 130 Yorkshire-Landrace sows, randomly allotted into two groups. Farrowing monitoring began 12 h after PGF2alpha synchronization. Group 1 was given physiological solution (G1, n = 65); Group 2 was treated with VC (1 mL/60 kg LW) at the initiation of fetal expulsion (G2, n = 65). In spite of the total duration of expulsion being significantly longer (P < 0.0001), approximately 35 min in the VC treatment, VC application at the time the first piglet was expulsed favored the alive birth of at least one more piglet. Even though the pressure in the uterus was similar in both groups, the number and duration of uterus contractions recorded were significantly less (P < 0.0001) in G2, favoring fewer births with acute fetal suffering, compared with that in G1. VC treated group compared with the control group also had fewer (5.01% vs. 24%) alterations in umbilical cords, as well as a lesser incidence of secondary apnea (2.08% vs. 7.46%) and bradycardia (1.94% vs. 7.61%), which favored a significantly higher vitality score (P < 0.002). With the intent to evaluate uterine activity in sows during the farrowing process, we propose using the equation used in human medical practices to calculate Montevideo Units applied to swine obstetrics for the first time.

Assessment of the vitality of the newborn: An overview

Four million newborns die in the world every year, and reports indicate that 98% of those deaths occur in developing countries. The infant mortality rate in children under 5 years of age in Mexico has decreased progressively, in contrast to the neonatal mortality rate, where the reduction was not significant. For this reason, it is necessary and important to have resources that make it possible to assess, rapidly and efficiently, the physiological status of newborns. The objective of this review is to identify the factors involved in the vigor of the newborn. This review will thus allow us to understand the relation that exists between the vitality scores and birth weight, the repercussions of the process of prenatal asphyxia, age of gestation and mortality. Once the factors involved in decreases in the vigor of the newborn have been reviewed, additional studies will be required to use animal models to test different pharmacological therapies that newborn humans have shown their value for early diagnosis and treatment, as a means of improving their physiological and hemodynamic condition during the first hours of extra uterine life, as this is a fundamental factor in their survival.

Physiological response to hypoxia in piglets of different birth weight

In the present study, we aimed to extend the characterization of the proposed naturalistic experimental model of piglets born with hypoxia by assessing the relationship between birth weight, intra partum asphyxia and gross indicators of neurophysiological alterations in newborn piglets. Three groups of 50 piglets each were classified according to their birth weight into normal (1000–1350 g), low (below 1000 g), and high (over 1350 g). In comparison to piglets within normal weight, those born with high birth weights showed acid-base imbalance as reflected by lower pH levels (7.03±0.01), hyper-capnia (88.50±13.20 mmHg), and lactic acidosis (lactate levels: 89.40±26.30). These piglets had lower viability scores (5.40±0.60) and longer periods of time to contact the udder (52.30±8.30) than piglets with normal birth weight. In conclusion, data show that piglets with birth weight over 1350 g are at a higher risk of gross neurophysiological deficits, probably secondary to neonatal hypoxia.

Foetal Monitoring, Uterine Dynamics and Reproductive Performance in Spontaneous Farrowings in Sows

Abstract Olmos-Hernández, A., Trujillo-Ortega, M.E., Alonso-Spilsbury, M., Sánchez-Aparicio, P., Ramírez-Necoechea, R. and Mota-Rojas, D. 2008. Foetal monitoring, uterine dynamics and reproductive performance in spontaneous farrowings in sows. J. Appl. Anim. Res., 33: 181–185. To determine the farrowing process and to evaluate the effect of parity on uterine dynamics and reproductive performance, 120 Yorkshire X Landrace hybrid sows, twenty for each parity number from 1 to 6 were used. Frequency, duration and intensity of contractions were monitored as indicators of uterine activity, foetal cardiac frequency (FCF) was monitored to determine fetal distress. Overall, farrowing duration was 189 min, contraction number and intensity were 40.9 and 9.89 mm Hg, respectively. Sixth parity sows had the shortest labor duration. The average number of fetuses with severe bradycardia and distress was 0.5. There was a significant increase (P=0.001) in the number of uterine contractions in gilts and second parity sows. First parity sows showed the highest intensity of contractions (12.30 mm Hg, P=0.001) and the largest number of delayed FCF decelerations, (0.90, P=0.004), which agrees too with a large average number of intra-partum stillbirths (0.90) found. The present study establishes the basic uterine dynamics of eutocic parturitions which may help in swine obstetrics to design uterotonic treatments reducing the stillbirth rate due to asphyxia. These findings emphasize a need for farrowing supervision, especially for first and over fifth parity sows.