Perinatal adaptation in animals

Vitality in Newborn Farm Animals: Adverse Factors, Physiological Responses, Pharmacological Therapies, and Physical Methods to Increase Neonate Vigor

Vitality is the vigor newborn animals exhibit during the first hours of life. It can be assessed by a numerical score, in which variables, such as heart rate, respiratory rate, mucous membranes' coloration, time the offspring took to stand up, and meconium staining, are monitored. Vitality can be affected by several factors, and therapies are used to increase it. This manuscript aims to review and analyze pharmacological and physical therapies used to increase vitality in newborn farm animals, as well as to understand the factors affecting this vitality, such as hypoxia, depletion of glycogen, birth weight, dystocia, neurodevelopment, hypothermia, and finally, the physiological mechanism to achieve thermostability. It has been concluded that assessing vitality immediately after birth is essential to determine the newborn's health and identify those that need medical intervention to minimize the deleterious effect of intrapartum asphyxia. Vitality assessment should be conducted by trained personnel and adequate equipment. Evaluating vitality could reduce long-term neonatal morbidity and mortality in domestic animals, even if it is sometimes difficult with the current organization of some farms. This review highlights the importance of increasing the number of stock people during the expected days of parturitions to reduce long-term neonatal morbidity and mortality, and thus, improve the farm's performance.

Sow Nutrition, Uterine Contractions, and Placental Blood Flow during the Peri-Partum Period and Short-Term Effects on Offspring: A Review

The birth process is a crucial event for piglet survival. Along with increasing litter sizes, not only has the duration of parturition increased, but placental blood flow per piglet has reduced and placental area per piglet has become smaller, making these piglets more susceptible for hypoxia. Diminishing the risk of piglet hypoxia by either reducing the total duration of parturition or increasing fetal oxygenation may reduce the incidence of stillbirth and early post-partum mortality. This review discusses options to do so by nutritionally supporting the sow in the final pre-partum period, after discussing the role of uterine contractions and placental blood flow. Providing sufficient energy seems to be a logical first step, but also other nutrients needed for uterine contractions, such as calcium, or enhancing uterine blood flow by using nitrate seem promising. These nutrient requirements may depend on litter size.

Intrinsic challenges of neonatal adaptation in swine

The losses of piglets in commercial pig farming remain at concerning levels and need to be addressed through the implementation of new sustainable breeding and management strategies. In fact, piglets are especially at risk in the first days of life. Both genetics and the farrowing process have been shown to impact piglet vitality. In addition, knowledge of the animal-intrinsic responses in adapting to extra-uterine life is particularly important but is scarcely described in the scientific literature. In this review, the three phases that constitute neonatal adaptation in the pig are systematically presented. The first phase of early adaptation involves primarily the development of cardiorespiratory function (within the first 10 min of life) as well as thermoregulatory processes and acid-base balance (up to 24 h of life). In the second phase, homeostasis is established, and organ maturation takes place (up to 14 d post natum). The final third phase aims at the development of neurological, immunological and muscular features (up to 28 d of life). The involvement of aggravating and ameliorating factors such as dystocia, low colostrum yield and heat supply is key to the development of strategies to reduce piglet losses and increase vitality. The insights are of particular value in addressing current concerns in pig farming and to further improve animal welfare in pig production across different management types.

[Effects of Buthus occitanus tunetanus envenomation on an experimental murine model of gestation]

Scorpion envenoming is less studied in pregnant victims. In this work, the effect of Buthus occitanus tunetanus on parturition in late pregnancy was studied in an animal model. Four groups of six primigravid female rats, each one at the 22nd day of pregnancy, were used. The first two groups had received an intra-peritoneal injection of 500 microg/kg of Buthus occitanus tunetanus crude venom or a physiological saline solution and left until foetal delivery. Then, the time elapsed until the first pup delivery and that separating the first and latest ones were measured. The other two groups served for the uterine electrophysiological activity exploration. Rats were anaesthetized, artificially ventilated and had received an intraperitoneal injection of 500 microg/kg of Buthus occitanus tunetanus crude venom or a physiological saline solution. Our results showed a significant increase of the latency to foetal delivery, labour time, and uterine contractile activity in envenomed rats compared to controls. Such signs are usually seen in dynamic dystocia. It was concluded that Buthus occitanus tunetanus envenoming might induce a dynamic dystocia, when it occurred in late pregnancy.

Acid–base balance of umbilical artery blood of liveborn piglets at birth and its relation with factors affecting delivery of individual piglets

In the limited number of studies that reported on the relation between factors affecting birth of individual piglets and acid-base balance values at birth, predominantly simple correlation coefficients have been used. The aim of the present study was to analyse the relation between factors affecting delivery of individual liveborn piglets and acid-base balance values (pH, PCO(2) , HCO(3)(-) and BE(ecf)) at birth. In total 201 piglets originating from 44 litters were used for the collection of blood samples from the umbilical artery immediately after birth, preferably in the period of apnea. Blood samples were analysed with the iStat Portable Clinical Analyser. Significantly lower pH, HCO(3)(-), BE(ecf) and significantly higher PCO(2) levels were found in posteriorly presented piglets, independently of the condition of the umbilical cord, birth weight and cumulative birth interval/rank. Independently of presentation, birth weight and rank, piglets born with ruptured umbilical cords showed significantly lower pH values. Next to that, increasing birth weights resulted in increasing HCO(3)(-) and BE(ecf) values at birth, independently of presentation, condition of the umbilical cord and cumulative birth interval/rank. Both an increase in cumulative birth interval and in rank was associated with a significant decrease of pH, HCO(3)(-), BE(ecf) and increase of PCO(2) levels in umbilical cord blood at birth. Together these results demonstrate for the first time that a clear relation exists between (factors affecting) the progress of delivery and acid-base balance values in a polytocous species like the pig.

Factors affecting duration of the expulsive stage of parturition and piglet birth intervals in sows with uncomplicated, spontaneous farrowings

Modern pig farming is still confronted with high perinatal piglet losses which are mainly contributed to factors associated with the progress of piglet expulsion. Therefore the aim of this study was to identify sow- and piglet factors affecting the duration of the expulsive stage of farrowing and piglet birth intervals in spontaneous farrowing sows originating from five different breeds. In total 211 litters were investigated. Breed affected duration of the expulsive stage significantly: the shortest duration was found in Large White x Meishan F2 crossbred litters and the longest duration in Dutch Landrace litters. No effect of parity on the duration of the expulsive stage was found. An increase in littersize (P<0.01), an increase in number of stillborn piglets per litter (P<0.05) and a decrease of gestation length (P<0.05, independently of littersize) all resulted in an increased duration of the expulsive stage of farrowing. A curvilinear relationship between birth interval and rank (relative position in the birth order) of the piglets was found. Besides that, piglet birth intervals increased with an increasing birth weight (P<0.001). Stillborn (P<0.01) and posteriorly presented (P<0.05) piglets were delivered after significantly longer birth intervals than liveborn and anteriorly presented piglets. The results on sow- and piglet factors affecting duration of the expulsive stage and piglet birth intervals obtained in this study contribute to an increased insight into (patho) physiological aspects of perinatal mortality in pigs.

Fetal development in the pig in relation to genetic merit for piglet survival

The objective of this study was to investigate if litters with different genetic merit for piglet survival differ in late fetal development. In total, 507 fetuses from 46 litters were delivered by Caesarean section at, on average, d 111 of gestation. All litters had known estimated breeding values for piglet survival (EBVps). The obtained range of EBVps of the litters was continuous, and the difference between litters with the lowest and highest EBVps was 16.4%. Analysis of relationships between fetal characteristics and EBVps was performed with litter averages, using linear regression analysis with inclusion of EBVps as a covariate. An increase in EBVps of the litter was associated with decreases in average placental weight (P = 0.01) and within-litter variation in placental weight (P = 0.02), and an increase in average placental efficiency (P = 0.08). Average fetal length decreased with increasing EBVps (P = 0.04), but weights of liver (P = 0.02), adrenals (P = 0.0001), and small intestine (P = 0.01) showed relative increases with increasing EBVps. Average serum cortisol concentrations increased with increasing EBVps (P = 0.0001), but the other blood characteristics (hematocrit, glucose, fructose, albumin, estradiol-17beta) were not related to EBVps. Glycogen concentrations in liver (P = 0.07) and longissimus dorsi muscle (P = 0.04) and total liver glycogen content (P = 0.05) increased with increasing EBVps, whereas heart glycogen concentration decreased with increasing EBVps (P = 0.005). The percentage of carcass fat increased with increasing EBVps (P = 0.05). Relationships of relative liver weight, relative small intestinal weight, and liver and muscle glycogen levels with EBVps were absent after adjustment for differences in cortisol levels between litters. The observed differences in fetal development in relation to EBVps suggest a higher degree of physiological maturity in litters with high EBVps. Differences in fetal cortisol most likely accounted for most of these maturational differences. The results imply that selection for improved piglet survival will lead to slightly smaller piglets that nevertheless have an improved ability to cope with hazards during birth or within the first days of life.

Effect of three resuscitation procedures on respiratory and metabolic adaptation to extra uterine life in newborn calves

The purpose of this study was to evaluate the effects of three resuscitation procedures on respiratory and metabolic adaptation to extra-uterine life during the first 24 h after birth in healthy newborn calves. Twenty-four newborn calves were randomly grouped into four categories: six calves did not receive any specific resuscitation procedure and were considered as controls (C); six received pharyngeal and nasal suctioning immediately after birth by use of a hand-powered vacuum pump (SUC); six received five litres of cold water poured over their heads immediately after birth (CW) and six were housed in a calf pen with an infrared radiant heater for 24 h after birth (IR). Calves were examined at birth, 5, 15, 30, 45 and 60 min, 2, 3, 6, 12 and 24 h after birth and the following measurements were recorded: physical and clinical examination, arterial blood gas analysis, pulmonary function tests using the oesophageal balloon catheter technique, arterial and venous blood acid-base balance analysis, jugular venous blood sampling for determination of metabolic, haematological and passive immune transfer variables. SUC was accompanied by improved pulmonary function efficiency and by a less pronounced decrease in body temperature. The "head shaking movement" and the subsequent temporary increase in total pulmonary resistance as well as the greater lactic acidosis due to CW were accompanied by more efficient, but statistically non-significant, pulmonary gas exchanges. IR allowed maintenance of higher body temperature without requiring increased catabolism of energetic stores. IR also caused a change in breathing pattern which contributed to better distribution of the ventilation and to slightly improved gas exchange. The results indicate that use of SUC, CW and IR modified respiratory and metabolic adaptation during the first 24 h after birth without side-effects. These resuscitation procedures should be recommended for their specific indication, i.e. cleansing of fetal fluid from upper airways, hypothermal stimulation of breathing and prevention of heat losses.