Teaching animal welfare in veterinary schools in Latin America.

There is a high demand for a veterinary education in animal welfare (AW) with different approaches from the academic, society and trade points of view. Latin American (LA) countries members of the World Organization for Animal Health (OIE) are under the urge and should be obligated to teach AW. The aims of this article are to analyze the current drives of change on the importance of teaching animal welfare in LA, the competences recommended from international education organizations for the region, and to provide the contents on the curriculum in AW that a future veterinarian should achieve in the LA scenario, in other words to examine why teaching AW, what should be taught and how. Despite significant advances in introducing AW into veterinary training programs, much remains to be done regarding the future of this field in teaching veterinary science in Spain and LA countries, and in including this science as an independent course in programs at distinct levels to integrate the scientific, ethical and legal aspects of AW. This paper presents a proposal that was constructed with a view towards integrating diverse curricular approaches based on criteria, contents and concepts provided by the researchers and professors who collaborated in the book entitled: Bienestar Animal: Una Visión Global en Iberoamerica [Animal Welfare: A Global Vision in Ibero-America]. To ensure veterinary students will be better equipped to graduate with OIE day 1 competencies in AW, teaching approaches are needed that support project-based learning and gamification, critical thinking, reflection and collaborative learning.

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.

Efecto de la aplicación de oxitocina en variables críticas sanguíneas de cerdas distócicas / Effects of oxytocin on critical blood variables from dystocic sows

The aim of the study was to monitor the sow maternal response to a low oxitocin dose in an advanced parturition stage in eutocic and maternal-foetal dystocia. Sixty York x Landrace sows, 30 with eutocic farrowing and 30 with maternal-foetal dystocia were assigned into two different groups: 15 received 0.083 IU/kg of oxytocin after the expulsion of the fifth piglet, and 15 received no treatment at all. Blood samples from every sow in trial were taken from the ear vein at three different times: immediately after membrane rupture, after the fifth piglet was born, and at the end of the farrowing. A third generation blood gas analyzer was used. Results show that when parturition was resumed, sows with maternal-foetal dystocia had significantly greater lactate, pCO2 and ear temperature (P < 0.001), compared with the eutocic sow group. Results from physiological variables and neonatal traits monitored in this experiment show evidence that oxytocin should not be used in normal parturition without stillbirths, since oxytocin in this case had adverse effects on sow performance. Oxytocin administered at the beginning of the second half of parturition decreased 50% the number of born alive with asphyxia in eutocic and dystocic sows, and on the other hand, decreased 50% the number of intra-partum stillbirths in the dystocic group. This is the first study describing the critical blood variables in dystocic sows (pH, pCO2, pO2, glucose, lactate and HCO3), using a third generation gasometry device.

Con el propósito de evaluar las respuestas maternas a dosis baja de oxitocina en estado avanzado del parto en cerdas con eutocia y distocia materno-fetal, se seleccionaron 60 cerdas de la cruza Yorkshire x Landrace, 30 eutócicas y 30 con distocia materno-fetal. Las cerdas de cada grupo fueron divididas en subgrupos: 15 recibieron 0.083 UI/kg de oxitocina después de la expulsión del quinto lechón, las otras 15 no fueron tratadas. Se obtuvieron muestras sanguíneas en cada una de las cerdas mediante punción de vena auricular después de la rotura de la fuente, al quinto lechón y al finalizar el parto; las muestras fueron evaluadas con un analizador de gases sanguíneos. Al finalizar el parto, las cerdas que presentaron partos con distocia materno-fetal incrementaron significativamente (P < 0.001) los niveles de lactato, pCO2 y temperatura, respecto de las hembras que presentaron partos eutócicos. Los resultados de las variables fisiológicas y los indicadores neonatales evaluados en este experimento son evidencia de que la oxitocina no debe aplicarse en partos con evolución normal sin nacidos muertos, ya que posee efectos adversos sobre el desempeño de la cerda. La oxitocina en cerdas, administrada al inicio de la segunda mitad del parto, disminuyó en 50% los nacidos con asfixia en cerdas eutócicas y distócicas; asimismo, redujo en 50% el número de muertes intraparto en las hembras distócicas. Los resultados del presente experimento determinan por primera vez la evolución de los parámetros críticos sanguíneos de la cerda con partos distócicos (pH, pCO2, pO2, glucosa, lactato y HCO3) utilizando equipo de gasometría de tercera generación.

Aspectos relevantes del bienestar del cerdo en tránsito / Relevant aspects of swine welfare in transit

Current globalization policies demand animal welfare standards on animal transportation. In spite of international tendencies to commercialize meat cuts while decreasing live animal transit, transport is still one of the major problems in terms of animal welfare, besides carcass and meat by-products' quality. The present review analyzes, in general terms, the different definitions on animal welfare and factors affecting pig welfare in transit. Several case studies are referred to as examples, showing the animal response to stress during transport and its effects on both meat quality and the economic impact. In addition, legal requirements and Mexican regulations for pig transportation are also described. Information in regard to swine stress and welfare in transit, considers a number of factors that alter the animal metabolic homeostasis with subsequent negative effects on pork quality. It is conclude that knowledge on basic animal behavioral and physiological needs during transport, as well as a suitable training of personnel, are necessary for reducing animal welfare problems. Last but not least, some recommendations on handling practices are given in order to improve swine welfare during transit.

En el marco actual de la globalización, hablar de transporte animal conlleva realizar prácticas que mejoren el bienestar animal, aunque existe la tendencia mundial de incrementar el mercado de la carne en cortes, así como disminuir el comercio de animales vivos, el transporte constituye uno de los factores más preocupantes en términos del bienestar animal, además del impacto en la calidad de la canal y los subproductos respectivos. En la presente revisión se analizan, en términos generales, las distintas definiciones de bienestar animal, así como los factores más importantes que alteran el bienestar de los cerdos durante el transporte; se describen los requisitos legales y la normatividad mexicana para el transporte de animales, así como varios estudios de la respuesta fisiológica del animal durante condiciones adversas del transporte, se señalan, además, las repercusiones sobre la calidad de la carne y su impacto económico. La información con respecto al estrés de los cerdos y su bienestar durante el transporte, considera numerosos factores que alteran el equilibrio homeostático animal y que propician efectos negativos sobre calidad de la carne. Se concluye que tanto el conocimiento de la biología de la especie, como un entrenamiento del personal, son necesarios para disminuir los problemas de bienestar. Finalmente, se recomiendan algunas prácticas derivadas de los hallazgos presentados, con el fin de que se mejore el bienestar de los cerdos en tránsito.

Analysis of normal and denerved laryngeal vocalization in guinea pigs (Cavia porcellus).

Paralysis of the left vocal chord is frequent in human clinical practice; because of its anatomic similarity with human, the guinea pig might be a suitable biological model to analyze the phoniatric behavior in denerved animals. Forty newborn guinea pigs were used (20 control and 20 experimental); an incision was made in the ventricular region with the animals under general anesthesia over the middle line of the neck, until the lower left laryngeal nerve was found, the same was secured with alligator clips so that afterward a two-part dissection could be performed and the middle section could be removed (1cm) from the nerve endings (distal and proximal) before they were separated from the laryngeal structure. After recovery from surgery, vocal emissions were recorded in solitary for 6 minutes. The animals that had nerves removed showed an increase in fundamental vocalization frequency compared with the controls. F test was carried out (P=0.05) and no significant difference was found. When analyzing functional recovery, we found that the guinea pigs compensated vocal emissions at 20 days. With regard to the unilateral paralysis, the motility was frequently compensated by the healthy vocal chord, improving voice emission, and loss of air inhalation.

Obstetric and fetal outcomes in dystocic and eutocic sows to an injection of exogenous oxytocin during farrowing.

Sixty hybrid Yorkshire-Landrace penned sows, 30 with eutocic farrowing and 30 experiencing a dystocic parturition, were studied to evaluate the obstetric and neonatal outcomes to low doses of oxytocin administered at advanced stages of parturition. Animals in each group were randomly subdivided into 2 subgroups: 15 eutocic and 15 dystocic sows received oxytocin 0.083 IU/kg (equivalent to 1 IU/12 kg body weight), administered intramuscularly after the delivery of the 5th piglet; the other 15 eutocic and 15 dystocic sows received saline solution intramuscularly at the same time. Oxytocin decreased the number of intrapartum deaths by approximately 50% (P = 0.002). No piglet was born dead from the saline- and oxytocin-treated eutocic sows. The highest viability score was observed among piglets born to eutocic sows treated with oxytocin. In summary, this dose schedule would help to decrease the number of stillbirths in both eutocic and dystocic farrowing sows.

Effects of sildenafil on the fetal growth of guinea pigs and their ability to survive induced intrapartum asphyxia.

OBJECTIVE: Our goal was to determine whether sildenafil increased fetal weight and favored fetal tolerance to induced asphyxia at birth in guinea pigs. STUDY DESIGN: Twenty guinea pigs were randomly allocated to placebo (n = 10) or sildenafil 50 microg/kg (n = 5) or 500 microg/kg (n = 5), starting from day 35 of gestation to delivery. Fetuses were delivered by cesarean section. Fetal asphyxia was induced by clamping the umbilical cord at birth for 5 minutes. RESULTS: Sildenafil protected the pups against induced asphyxia at birth in a dose-dependent manner (eg, partial pressure (tension) of carbon dioxide levels were 75.9 +/- 19.3, 66.9 +/- 18.8, and 54.8 +/- 13.0 in the control and low- and high-dose sildenafil groups, respectively). The high-dose sildenafil group of piglets gained 1.5 times more body weight. CONCLUSION: In guinea pigs, low doses of sildenafil administered from day 35 to the end of gestation favored fetal tolerability to induced intrapartum asphyxia. High doses of sildenafil increased fetal weight.

A study of piglets born by spontaneous parturition under uncontrolled conditions: could this be a naturalistic model for the study of intrapartum asphyxia?

In order to evaluate how spontaneously born piglets could be a suitable model for the study of intrapartum hypoxia, 230 newborn piglets were studied. Out them, 8.3% (n = 19) died intrapartum, 21.7% (n = 50) were born with moderate-to-severe intrapartum hypoxia, and 70% (n = 161) were born with mild or no evidence of intrapartum distress. Piglets born without any evidence of intrapartum asphyxia weighed approximately 240 g lower than those born with intrapartum hypoxia and intrapartum-dead piglets (P<0.0001). The viability score was approximately 3 units lower and the latency to contact the udder was two times longer in the piglets surviving intrapartum hypoxia than in controls (P <0.0001). In comparison with the control group, metabolic acidosis was most severe among intrapartum-dead piglets followed by piglets surviving intrapartum asphyxia (P =0.002). According to a multiple linear regression analysis, pCO2 and lactate blood levels, and birth weight were identified as explanatory variables of viability score (r: 0.78; P <0.001). Viability score, K+ and lactate blood levels, and birth weight were identified as explanatory variables of latency to contact the udder (r: 0.80; P <0.001). In conclusion, the spontaneously-born asphyxiated piglet could be considered as a naturalistic model for the study of intrapartum asphyxia. Histopathologic and more rigorous functional and behavioral evaluations are still required to further characterize the model. (www.actabiomedica.it)

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.

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 percent 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.

Morphological changes in the lungs of meconium-stained piglets.

Meconium staining of the skin is a common event associated with fetal hypoxia, stillbirths, weak-born piglets, and neonatal mortality. Aspiration of meconium leads to meconium aspiration syndrome (MAS). This study was undertaken to assess the relationship between the degree of meconium staining of the skin at birth, meconium aspiration, and pulmonary changes in porcine neonates. A total of 353 farrowing sows and 3,693 born piglets were monitored during parturition and for 15 days after delivery. Umbilical cords were classified as normal or ruptured. Meconium staining in the skin was graded as nonstained, mildly, moderately, and severely stained. Mortality from birth to 15 days of age was 8.4%. The lungs from 60 meconium-stained piglets and 60 lungs from nonstained piglets were collected and microscopically examined for meconium aspiration and inflammation. Rupture of the umbilical cord was significantly higher (P < 0.01) in meconium-stained piglets. Microscopically, 32% and 40% of the lungs had evidence of meconium for the stained and nonstained groups, respectively. The microscopic grade of meconium aspiration and inflammatory cells was not different between nonstained and meconium-stained piglets. Aspiration of meconium induced a granulomatous response in the lungs. It was concluded that the grade of meconium staining is a good indicator of fetal hypoxia, but not a good predictor for meconium aspiration and MAS in piglets.

Obstetric and neonatal outcomes to recombinant porcine somatotropin administered in the last third of pregnancy to primiparous sows.

This study aimed to investigate whether the administration of recombinant porcine somatotropin (rpST) late in gestation is associated with increased rates of obstetric and neonatal complications in primiparous sows. From days 80 to 114 of gestational age, 20 primiparous sows were randomly assigned to receive an intramuscular injection of either saline or 6 mg rpST/day. Throughout pregnancy, sows were fed 2.5 to 3 kg/day of a corn-soybean diet (14 MJ ME/kg). Of 111 piglets born to control sows and 109 piglets born to treated sows, 8.1% and 17.4% piglets respectively died intrapartum (P=0.04). Glucose blood levels in sows and live-born piglets in the rpST-treated group were significantly higher than in their corresponding controls. Birth weight of live-born piglets in the treated group was 1.4 +/- 0.1 kg versus 1.3 +/- 0.1 kg in the control group (P<0.0001). Birth weight of piglets born dead was also higher in the former than in the latter group (P<0.0001). No evidence of teratogenicity was observed in either of the groups. In conclusion, rpST administration in late pregnancy to primparous sows increased the rate of neonatal deaths and was associated with higher blood glucose levels in both sows and piglets.

Comparative routes of oxytocin administration in crated farrowing sows and its effects on fetal and postnatal asphyxia.

Oxytocin is used to induce and control parturition; nevertheless, an increase in uterine contractions decreases blood flow and gaseous exchange through the uterus predisposing to intra-partum mortality in pigs. The objective of the present study was to evaluate the effect of different oxytocin administration routes on myometrial activity, fetal intrauterine hypoxia and postnatal asphyxia in crated farrowing sows. Yorkshire x Landrace hybrid sows (n = 300), that were approaching the time of parturition, were randomly assigned into six groups. Each group included 50 sows, 10 for each of the parities from one to five. A 40-IU oxytocin dosage was administered by intramuscular (IM), or intravulvar (IVU) routes, or 20 IU was administered via intravenous (IV) route. Groups 1 (G1), 3 (G3) and 5 (G5) were administered 0.9% saline solution (NaCl) IM, IVU and IV, respectively, whereas groups 2 (G2), 4 (G4) and 6 (G6) were treated with oxytocin IM, IVU and IV, respectively. There was a significantly (P < 0.05) greater number of intra-partum stillbirths (IPS) for the oxytocin treatments, as compared with the control groups, especially with the IVU and IV routes; a lesser number of IPS and lesser IPS with broken umbilical cords was observed with the IM administration route. Oxytocin and control IV administration resulted in longer farrowing durations. Administration of IV-oxytocin resulted in a greater number (P < 0.05) of intrauterine distressed neonates compared with its corresponding control and interpreted through dips II, a fetal cardiac frequency deceleration which determines acute fetal suffering. Independent of the route of oxytocin administration, the treatments resulted in twice as many dips II compared with the respective control groups. The use of the cardiotocograph proved to be an excellent tool for establishing the oxytocin response dose in farrowing sows. A greater number of piglets born alive, which had undergone bradycardia, also showed severe acidosis and greater meconium staining in oxytocin-treated sows, indicating that the administration time (at birth of the first piglet) as well as the dosage used were not adequate treatment regimens in the present study. Further studies will be conducted to evaluate different dosages and oxytocin administration timing to determine the most desirable treatment regimen to increase myometrial contractibility without compromising fetal welfare and neonatal survival.

Perinatal asphyxia pathophysiology in pig and human: a review.

In utero fetuses are evidently exposed to several factors that cause an interruption of the oxygen flow through the umbilical cord causing asphyxia leading to hypoxia and metabolic acidosis. These conditions are important causes of intra-partum and neonatal mortality. The main objective of this review is to provide current information regarding the pathophysiology of asphyxia in piglets around parturition; the physiological mechanisms invoked by affected piglets to compensate perinatal hypoxemia are discussed. This review also addresses some similarities and differences of asphyxia between piglets and other mammals, including human neonates. Metabolic acidosis and hypoxia are sequela to asphyxia and can cause profound health effects in postnatal performance because of an abnormal suckling, a reduced absorption of colostrum and inadequate passive transfer of neonatal immunity. Acidosis also cause hypothermia, increased mortality and reduced survival in neonates. One of the first deleterious effects of intrauterine hypoxia is the expulsion of meconium into the amniotic sac leading to meconium staining of the skin, and in severe cases, meconium aspiration into the lungs. Even though there have been technological changes and improvements in husbandry, piglet mortality due to asphyxia remains a major problem. One potential alternative to reduce neonatal mortality in pigs is the monitoring of fetal stress during birth and the implemention of strategies such as the Apgar score, that is often used in human pediatrics. It is also important to consider the physiological, behavioral and biochemical changes that take place during parturition which subsequently impact the vitality, maturity and development of neonatal pigs. Understanding the pathophysiology of fetal hypoxia should help practitioners and farmers implement more effective delivery techniques aimed at reducing neonatal mortality and improving postnatal performance.

Uterine and fetal asphyxia monitoring in parturient sows treated with oxytocin.

Oxytocin is used to induce and control parturition, nevertheless, the increase of uterine contractions decreases blood flow and gaseous exchange through the womb predisposing to intra-partum mortality. The objective of the present study was to evaluate the effect of oxytocin on myometrial activity, fetal intrauterine hypoxia and postnatal asphyxia in sows during farrowing. Hybrid (n = 120) sows approaching the time of farrowing were randomly assigned in two groups of 60 animals each. Group I (G(1): control) was treated IM with saline solution and Group II (G(2)) was injected IM with oxytocin (1IU/6kg LW) as a single dose at birth of the first piglet. Both average number of myometrial contractions and intensity in G(2) were greater (P < 0.01) as compared with G(1). The mean of intra-partum stillbirths (IPS's) and those where fetal cardiac frequency (FCF) or heart beats, could not be detected after birth, were greater (P < 0.01) in G(2) as compared with G(1). The average decelerations of FCF known as dips II, which indicate severe hypoxia, was greater in G(2) (P < 0.01) as compared with that of G(1). There was a greater (P < 0.01) number of intra-partum stillbirths, stained with severe meconium in G(2) when compared with G(1). Oxytocin treatment increased (P < 0.01) the number of pigs born alive with ruptured umbilical cords and those with different grades of meconium staining on their skin. It was concluded that administration of oxytocin at the onset of parturition increased the myometrial activity, decreased fetal cardiac frequency, predisposed the rupture of umbilical cords and the degree of meconium staining, and increased intra-partum mortality.

Changes of vaginal epithelium in creole pigs ovulating during lactation

O objetivo deste estudo foi identificar mudanças do epitélio vaginal em fêmeas de Cerdo Pelón Mexicano, que ovularam durante o lactação, estágio causado pelo efeito da presença de macho e retirada da leitegada. A avaliação do estro foi feita através de citologia de raspado vaginal, observação do comportamento das fêmeas e por determinação de 17 ß estradiol e de progesterona no 8° dia após o início de lactação. Foram formados quatro grupos de fêmeas: Grupo 1 não sofreu estímulo; Grupo 2 permaneceu com o macho; Grupo 3 foi separado sua leitegada por 4 h e grupo 4 recebeu ambos estímulos. Amostras de raspado vaginal foram coletadas a cada 24 horas durante 5 dias após o estímulo. ANOVA para amostras repetidas foi realizada durante os 5 dias do teste. O estímulo utilizado no Grupo 4 causou modificações significativas (P < 0 001) quando comparado aos Grupos 1, 2 e 3. Os níveis de estradiol foram mais altos que 30 pg/ml no Grupo 4 no 10° dia pós parto e 4.5 ng/ ml de progesterona nos 11 ° e 12° dias pós parto. Ficou evidente que 100% das fêmeas nos Grupos 1,2 e 3 não mostraram atividade de estro quando foi relacionado citologia vaginal com o comportamento estral e determinação hormonal da fase de lactação das fêmeas, ao passo que 100% das fêmeas no Grupo 4 apresentaram estro 72 horas após os estímulos e ovularam 24 a 36 horas do início do cio, o que foi comprovado pela determinações de estradiol e progesterona, respectivamente.

Use of oxytocin in penned sows and its effect on fetal intra-partum asphyxia.

The objective of the present study was to evaluate in penned sows the effect of two commercial oxytocin products on umbilical cord pathology, degree of asphyxia and intra-partum mortality. This study included 120 sows divided in three groups of 40 animals with eight animals for parities one to five per subgroup, respectively. Group 1 (G(1)) or control received saline solution while oxytocin groups (G(2)) and (G(3)) were injected at the onset of fetal expulsion with two oxytocin products. The doses of oxytocin were as follow: Primiparous sows weighing less than 130 kg received 20 IU; multiparous sows weighing 130-180 g received 30 IU, and those above 250 kg, 40 IU. Piglets born alive and/or dead were classified at birth using a subjective scale based on the degree of meconium staining on skin. Umbilical cords of intra-partum stillbirths (IPS) were classified as adhered or ruptured and subdivided into four categories: without pathological changes, edematous, congested and hemorrhagic. Result analyses revealed significant differences (P < 0.01) between groups 1 and 2, and 1 and 3 regarding the following traits: expulsion interval (min) (X: G(1) 27.7; G(2) 22.6; G(3) 22.2), IPS with a severe stain degree (X: G(1) 0.10; G(2) 0.45; G(3) 0.50), IPS with ruptured umbilical cords (X: G(1) 0.07; G(2) 0.42; G(3) 0.47), and detectable heartbeats in IPS (X: G(1) 0.27; G(2) 0.25; G(3) 0.22). Treatment with oxytocin reduced the duration of the expulsion of the fetus, increased the number of IPS with ruptured umbilical cords and with severe meconium-stain degree and reduced the number of fetuses with inspiration attempts. Furthermore, the use of this hormone increased the need for obstetric assistance due to increased frequency of dystocia.

Efecto de la pérdida de grasa dorsal y peso corporal sobre el rendimiento reproductivo de cerdas primíparas lactantes alimentadas con tres diferentes tipos de dietas / Effect of loss of backfat and body weight on the reproductive performance of primiparous lactating sows fed with three different diets

Se evaluaron 90 cerdas híbridas primíparas de traspatio, que se clasificaron de acuerdo al tipo de dieta en 3 grupos: G1, escamocha (residuos alimenticios de consumo humano); G2, escamocha y concentrado y/o granos, y G3, alimento balanceado. La grasa dorsal se registró a la altura de la décima vértebra torácica mediante ultrasonido. Para evaluar el efecto de las reservas corporales sobre 10 indicadores productivos se utilizó la prueba exacta de Fisher; con una significancia de P<0,01. Los resultados señalaron diferencias significativas entre los tres grupos en los indicadores: peso (Kg) de la cerda al parto (X: G1 101,66; G2 111,3; G3 124,1) y al destete (X: G1 94,30; G2 104,5; G3 118,9); grasa dorsal (mm) al parto (X: G1 11,20 G2 12,66; G3 16,2) y al destete (X: G1 9,46; G2 10,70; G3 13,7); intervalo (días) destete estro (X: G1 23,16 G2 20,1; G3 14,5) y destete concepción (X: G1 27,43; G2 23,73; G3 17,16), y peso (g) individual del lechón al nacimiento en el segundo parto (X: G1 891,40; G2 958,5; G3 1054). En todos los grupos las cerdas perdieron en promedio 6 kg y 2 mm de grasa. Estos datos confirman que a medida que la calidad nutritiva de la dieta mejora, decrecen progresivamente los días que las cerdas requieren para entrar en calor una vez que son destetadas. A pesar del bajo peso al destete de las cerdas con alimentación con base en escamocha, éstas entraton en estro y su gestación fue exitosa aunque con un número moderado de lechones nacidos vivos y un pobre peso al nacimiento

Lactational estrus induction in the Mexican hairless sow.

The purpose of this study was to determine the effects on the reproductive performance of the Mexican hairless pig (MHP) while inducing fertile lactational estrus. Lactational estrus was induced on day 8, postpartum, in 20 primiparous sows during two consecutive reproductive cycles. Boar presence and temporary litter withdrawal were used as stimuli. Group I did not receive stimuli (control, C); group II had a 15 min boar stimulus (B); group III had litter withdrawal for 4 h (LW), and group IV received both stimuli (B + LW). Fertile estrus was detected by sow behavior, exfoliative vaginal cytology, and 17 beta-estradiol and progesterone samples. Individual stimuli did not induce fertile lactational estrus; nevertheless, when used together, both stimuli induced 100% of females into estrus, and 80% of them got pregnant while lactating. The partial withdrawal of the litter had a significant and positive effect on the number of live born piglets. Sows pregnant during lactation had shorter reproductive cycles, by not having non-productive days and litter size was greater. Pregnancy induction during lactation allowed the Mexican hairless sow to reduce the period between parturition's without diminishing the lactation length and litter performance.