María Alonso-Spilsbury

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.

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.

Histamine H3 receptor activation prevents dopamine D1 receptor-mediated inhibition of dopamine release in the rat striatum: a microdialysis study.

Histamine H3 receptors (H3Rs) co-localize with dopamine (DA) D1 receptors (D1Rs) on striatal medium spiny neurons and functionally antagonize D1R-mediated responses. The intra-striatal administration of D1R agonists reduces DA release whereas D1R antagonists have the opposite effect. In this work, a microdialysis method was used to study the effect of co-activating D1 and H3 receptors on the release of DA from the rat dorsal striatum. Infusion of the D1R agonist SKF-38393 (0.5 and 1 μM) significantly reduced DA release (26-58%), and this effect was prevented by co-administration of the H3R agonist immepip (10 μM). In turn, the effect of immepip was blocked by the H3R antagonist thioperamide (10 μM). Our results indicate that co-stimulation of post-synaptic D1 and H3 receptors may indirectly regulate basal DA release in the rat striatum and provide in vivo evidence for a functional interaction between D1 and H3 receptors in the basal ganglia.

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.

Effect of prostaglandins for inducing birth on weight, vitality and physiological response in newborn pigs.

Abstract Sánchez-Aparicio, P., Mota-Rojas, D., Trujillo-Ortega, M.E., Zarco-Quintero, L.A., Becerril-Herrera, M., Alonso-Spilsbury, M. and Alfaro-Rodríguez. A. 2008. Effect of prostaglandins for inducing birth on weight, vitality and physiological response in newborn pigs. J. Appl. Anim. Res., 36: 113–118. To evaluate the effect of prostaglandin administration to induce farrowing on incidence of stillbirth (SBP), evidence of intra-partum hypoxia (HBP) and weight, viability and acid-base equilibrium in piglets at birth, 395 newborns product of 40 Yorksh1ire × Landrace hybrid were studied upon. Sows were randomly divided equally into two treatments. Treatment 1 (T1) received 2 ml of an intramuscular (IM) normal saline solution and Treatment 2 (T2) was treated with a single dose of 10 mg IM of prostaglandin analogue, to induce a synchronized parturition 48 h before the estimated time of parturition. The weight of the SBP was approximately 142 g less (P<0.0376) in T2 (PGF2α, compared with the T1. The weight of the HBP was approximately 247 g less (P<0.0001) in T2 compared to T1. The vitality score of ABP was good in both treatments. Two response variables (glucose, Ca++) in ABP were significantly greater in T2 compared to T1. When PGF2α was injected in the sow 48 h before giving birth, it has negative effects causing hyperglycemia and low weight at birth and diminished vigor in the newborn piglets. However, further studies with variable time interval are recommended.

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.

Home Range Size and Activity Patterns of Bobcats (Lynx rufus) in the Southern Part of their Range in the Chihuahuan Desert, Mexico

Abstract Home range size, daily travel distances, and diel activity patterns are important characteristics of how an animal uses its home range area. In species, such as the bobcat (Lynx rufus), with large geographical ranges, it is necessary to gather data on diverse populations across the range to better understand what might be factors influencing these home range parameters. Although there are many studies of bobcats in more northern areas of its range in the United States, few data exist from its extensive southern range in Mexico. To fill this gap in information, we collected data on home range size, daily travel distances, and diel activity patterns of bobcats from the center of the Chihuahuan Desert in Mexico. We compared our findings with available data from more northern studies and tested for any latitudinal trends in home range size. We trapped eight adult bobcats (four females and four males) between 2006 and 2008 at the Mapimi Biosphere Reserve in the Chihuahuan Desert. Each bobcat was equipped with a GPS radio collar that estimated their location and ambient temperature every half hour at night (1900 to 800 h), and every hour during the day (800 to 1900 h). These data were used to estimate total daily distance traveled, average speed, home range size, activity pattern, and to test for an association between hourly travel and ambient temperature. For bobcats in Mapimi, mean distances traveled daily (4.9 ± 0.7 km), mean speed (0.3 ± 0.4 km/h) and average home range size (25.9 km2 ± 3.7) did not differ from other places in U.S. (distance traveled daily 5.7 ± 1.4 km, mean speed 0.4 ± 0.4 km/h and home range size 34.0 ± 5.4 km2). Bobcats are most active from 1700 to 2300 h and from 0500 to 1200 h and showed a minimum activity period from 1300 to 1600 h. These patterns did not differ from what other studies found. Distance traveled was inversely correlated with environmental temperature (r2  =  0.506, P < 0.05). Our data demonstrate that most behaviors of bobcats in this hot desert environment did not differ in general from their more northern populations. Although our home range estimates were similar to other studies, our analysis did support a latitudinal decreasing trend that indicates factors other than those related to latitude are affecting home range size in bobcats. We suggest investigating other independent factors not related with latitude such as primary production and rainfall might help identify which, if any, of these factors contribute to home range size in bobcats.