Viability of Iberian x Meishan F2 newborn pigs. I. Analysis of physiological and vitality variables

The influence of hypothermia prevention by application of skin moisture absorbent on the value of body temperature, body weight and blood parameters in piglets

ABSTRACT Reducing the mortality rate is of a great economic importance for pig farming. Therefore, it is necessary to define the conditions in the farrowing unit based on the performance of the piglets, and specific hematological and biochemical parameters. Therefore, the aim of this paper is to examine the importance of using skin moisture absorbent and its influence in preventing hypothermia, which causes great economic losses in pig production. The experiment was set up on a commercial farm in Serbia and included 92 pigs divided into the experimental and control group. Body temperature values, body weight and blood parameters were monitored. The obtained values indicate that there is a significantly positive correlation of body temperature change and body weight values, and body temperature showed a significantly higher increase in the experimental group compared to the control group. The results obtained from hematological and biochemical parameters provide a clearer picture of the metabolic processes in piglets in the farrowing unit and can be used to further improve pig production and as a complement to genetic enhancement.

Glucose and glycogen levels in piglets that differ in birth weight and vitality

In the pig, intrauterine crowding can greatly affect postnatal characteristics, among which birth weight and locomotion. In a previous study, we discovered that piglets with a low birth weight/low vitality (L piglets) have a reduced motor performance compared to piglets with a normal birth weight/normal vitality (N piglets). A possible explanation is that L piglets lack the energy to increase their motor performance to the level of that of N piglets. Blood glucose levels (GLU) and glycogen concentrations in skeletal muscle of the front (GLY_FRONT) and hind leg (GLY_HIND) and the liver (GLY_LIVER) at birth and during the first 96 h postpartum were compared between L and N piglets. GLU at birth was the same for both groups. After birth, GLU immediately increased in N piglets, whereas it only increased after 8 h in L piglets. L piglets showed a lower GLY_HIND at birth and did not use this glycogen during the first 8 h postpartum, while N piglets showed a gradual depletion. GLY_LIVER at birth was 50% lower for L piglets and was unused during the studied period while N piglets consumed half of their GLY_LIVER during the first 8 h. Based on these results, it is possible that lower glycogen concentrations at birth, the delayed increase in GLU and the lower use of glycogen during the first 8 h after birth negatively affect motor performance in L piglets. However, based on this study, it is unclear whether the low mobilization of glycogen by L piglets is a consequence, rather than a cause of their lower motor performance.

Neurophysiological development of newborn pigs: effect of the sow

The objective of the present study was to determine the effect of sow parity on neonatal piglet health and vitality at birth. We evaluated 1505 neonate piglets, which were born of York–Landrace sows with the following parity distribution: primiparous (n = 202), second (n = 207), third (n = 211), fourth (n = 222), fifth (n = 225), sixth (n = 218) and seventh parity (n = 220). Piglets born to primiparous and seventh-parity sows had the lowest and highest birthweights respectively, and showed the most marked imbalances in blood gas exchanges, acid–base balance and energy profiles, as well as the highest percentage of severe meconium staining of the skin and the lowest vitality scores (P < 0.05). In contrast, the neonates from the fourth-parity sows had the highest vitality scores, required less time to reach the mother’s teat, and had the highest percentage of adhered umbilical cords and newborns with dyspnoea, apnoea and abnormal heartbeat (P < 0.05). The results of this study suggest that during eutocic farrowings, the sow’s parity number has the following effects on newborn piglets: reduced vigour and longer latencies to begin breathing, stand and take the teat. These effects are due to the presence of imbalances in gas exchanges, the acid–base balance and energy profiles that occurred when the mother was a primiparous or older sow. These signs indicate that the newborn piglet survived a process of intrapartum asphyxia.

Relationship of sow udder morphology with piglet suckling behavior and teat access

The aim of this study was to investigate if there is a relationship between the latency to the first suckling and udder and teat morphology and to assess the extent to which piglet and sow characteristics influence teat pair position preference. Udder morphology trait measurements, piglet suckling behavior, and sow productive and behavioral traits were recorded from a population of 74 Large White X Landrace sows of different parities. The interteat distance within the same row was larger between the teats that were suckled at the first contact with the udder compared with the unsuckled teats (P = 0.04). There was a tendency for piglets to suckle first from teats placed closer to the abdominal midline. A high proportion of siblings (64%) suckled for the first time on a teat previously chosen by another piglet. Most neonates suckled first from a teat located in the posterior part of the udder (41%) or in the anterior part (33%), rather than the middle section. Latency from birth to suckling and the time from the first udder contact to locate a teat and suckle was shorter for piglets first suckling the anterior (28:03 and 9:48 minutes) and posterior teats (26:31; 8:38 minutes) than for those sucking the midsection teats (34:30 minutes, F7,256 = 1.99, P = 0.05; 10:30, F7,256 = 2.37, P = 0.05). To avoid possible confounds, other potential causes of delay in successful suckling were studied. The latency to suckle was not influenced by piglet vitality score at birth, weight, or provision of human assistance to place it at the udder. It was shorter when the piglets were born later in the litter (P < 0.001), from a litter with a low incidence of piglets born dead (P = 0.001) and from a sow with an induced farrowing (P = 0.007). Moreover, there was a tendency for piglets born from a multiparous sow (P = 0.06) and in a large litter size (P = 0.07) to have a longer latency to find a teat and suckle once they had made the first contact with the udder. Although suckling itself is clearly an instinctive behavior, acquisition of colostrum depends on many variables, relating not only to piglet characteristics but to sow behavioral and morphological characteristics as well. Future studies on sow characteristics are therefore recommended.

Piglet behavior as a measure of vitality and its influence on piglet survival and growth during lactation

The aim of the study was to develop a vitality scoring method, based on piglet behavior and relate it to piglet growth and survival. From 21 sows (Sus scrofa), 287 piglets were used. After farrowing (d 0), piglets were weighed and tested for 4 behavioral parameters in a circular enclosure (55 cm diam.): movement capacity (M), udder stimulation (U), number of completed circles around the enclosure (NCC), and screaming (Sc). Piglets were weighed again on d 1, 2, 3, and 17. Piglet rectal temperature (RT) was recorded on d 0, 1, 2, and 3. Farrowing information of the sow was also recorded. Multiple regression analyses for survival and BW gain at weaning as dependent variables were performed. Piglet BW gain at weaning was influenced by BW at birth (P < 0.001), sow parity (P = 0.024), total number of piglets born alive per sow (P < 0.001), and sum of U and NCC parameters (UN; P = 0.023). Piglet survival during lactation was influenced by BW at birth (P = 0.015), UNCC parameter (P = 0.026), and RT on d 3 (P = 0.085). The sum of U and NCC parameters, in combination with BW at birth and information of the sow, might be useful to predict piglet growth survival during lactation, thus becoming a useful tool to improve piglet management during the first days of lactation. In conclusion, UNCC parameter seems to be an easy and useful way to assess piglet vitality for both scientific and commercial purposes.

Newborn piglet traits associated with survival and growth performance until weaning

Pre-weaning piglet mortality represents significant economic losses, and approximately half of this mortality occurs within the first 3 days after birth. Factors involved in postnatal mortality can also be associated with a poor growth performance until weaning. The aim of this study was to evaluate the effect of some variables measured right after birth on piglet survival during the first week of life and growth performance until weaning. Piglets included in the analysis (n=612) were born from 3 to 5 parity sows. Piglets were monitored for blood oxygen saturation (SatO2), heart rate (HR), blood glucose concentration, rectal temperature at birth (RT0 h) and at 24h after birth (RT24 h). Genetic line, birth following or not an obstetric intervention, birth order, sex, skin color, integrity of the umbilical cord, and time elapsed from birth until first attempts to stand were also recorded. Piglets were weighed at birth (BW), and at 7, 14 and 21 days after birth in order to evaluate their postnatal development. Cumulative mortality rates were 3.3%, 5.4% and 8.7% at 3, 7 and 21 days after birth, respectively. Body temperature at birth (RT0 h) did not affect (P>0.05) the survival nor the piglet growth performance. Piglets with cyanotic skin and those that took more than 5 min to stand showed higher chance of mortality (P<0.05) compared to normal skin piglets and to piglets which stood before 1 min, respectively. Piglets with broken umbilical cord had higher odds (P<0.05) of mortality up to 3 days after birth, respectively. Higher odds (P<0.05) of mortality up to 3 or 7 days were associated with later birth order (>9), low BW (<1275g), low (24-30 mg/dl) and high (45-162 mg/dl) blood glucose concentrations, or low RT24 h (<38.1°C). Piglets with BW<1545 g, low RT24 h (<38.6°C) and female piglets had higher odds of a low weight at weaning (P<0.05). Among the factors studied, cyanotic skin, delay for standing, broken umbilical cord, high birth order, low BW, low RT24 h, and both low and high blood glucose concentrations are indicators of a lower ability of piglets to survive during the first week after birth. The growth performance until weaning is compromised in piglets with a lower BW, a lower RT24 h and if they are female pigs.

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).

High amino acid variation in the intracellular domain of the pig prolactin receptor (PRLR) and its relation to ovulation rate and piglet survival traits1

Two polymorphisms of the porcine prolactin receptor (PRLR) gene were previously related to litter size by several authors; however, the magnitude and direction of such effects varied depending on the population analyzed. We have sequenced the complete coding region of the porcine PRLR gene and found 6 nonconservative SNP: C1217T (Leu/Pro406), C1283A (Asp/Ala428), G1439A (Lys/Arg480), T1528A (Met/Leu510), G1600A (Gly/Ser534), and G1789A (Gly/Ser597), within exon 10 of the gene, which encodes the entire intracytoplasmic domain of the protein. Eight haplotypes were found and were segregating at different frequencies in 6 porcine breeds. The effects of each individual SNP and haplotype were evaluated in an Iberian x Meishan F2 population using a univariate mixed-inheritance animal model. Significant effects on the number of corpora lutea were found for PRLR haplotypes (P < 0.012), confirming the previously reported associations of PRLR in this process and highlighting the importance of performing analysis of haplotypes rather than of individual SNP. Suggestive effects or tendencies were found for heart rate at birth (P < 0.10), rectal temperature (P < 0.05), and oxygen saturation (P < 0.10) 1 h after birth, and time to first suckle (P < 0.10). We found greater than expected levels of amino acid variability within the intracellular domain of the porcine PRLR, which have been associated with differences in the number of corpus lutea of sows and the preweaning survivability of piglets.

Polymorphisms of the porcine dopaminebeta-hydroxylase gene and their relation to reproduction and piglet survivability in an Iberian x Meishan F2 intercross

The goals of this study were to sequence and physically map the porcine dopaminebeta-hydroxylase (DBH) gene, as well as to perform an association study between polymorphisms of this gene and the reproductive performance and piglet survivability of F(2) pigs from an Iberian x Meishan cross. The porcine DBH gene was positioned by RH mapping near the telomere of chromosome 1q2.13, close to markers SSC10D08 and SW1301. Sequencing of DBH cDNAs from 10 pigs revealed the existence of six nucleotide polymorphisms, two of which led to non-synonymous amino acid substitutions within exon 3 at positions 463A>G and 616A>G that corresponded to Thr155Ala and Lys206Glu respectively. Three haplotypes segregated in an Iberian x Meishan population: DBH(X) (A(436)-A(616)), DBH(Y) (A(436)-G(616)) and DBH(Z) (G(436)-G(616)). The DBH haplotypes significantly affected rectal temperatures 1 h after birth (P = 0.002) and have a suggestive effect on the time to first colostrum intake (P = 0.019) and on birth weight (P = 0.019).

Bayes factor analysis for the genetic background of physiological and vitality variables of F2 Iberian x Meishan newborn piglets

The Bayes factor (BF) procedure was applied to examine the additive genetic component of several physiological and vitality variables for newborn pigs. Nine variables were studied: heart rate, arterial oxygen saturation, rectal temperature (all at birth and 60 min later), birth weight, interval between birth and first teats contact, and interval between birth and first colostrum intake. The available numbers of data ranged from 288 (heart rate at 60 min) to 839 records (birth weight) from F(2) Iberian x Meishan newborn pigs. We compared a model with zero heritability (nonheritable) with the one where the additive genetic background was included. The BF was used to discriminate between both candidate models. Very strong evidence of genetic background was detected for heart rate 60 min after birth (BF = 48.90), and strong evidence was detected for rectal temperature at birth (BF = 13.82). Posterior modes (means) of heritabilities were 0.29 (0.32) and 0.40 (0.39), respectively. In addition, substantial evidence of absence of genetic background was detected for arterial oxygen saturation at birth.

Viability of Iberian × Meishan F2 newborn pigs. II. Survival analysis up to weaning1

Iberian x Meishan F2 piglet's preweaning survivability was analyzed using categorical data regression procedures within the proportional hazards assumption. A frailty sire model was assumed with the litter effect treated as an additional random source of variation. Moreover, the relative birth weight within litter and the litter effect were considered time-dependent covariates that changed their values in the second day of life due to cross fostering carried out to standardize litters. Six variables had a significant effect on survivability: birth weight (P < 0.01), relative birth weight within litter (P < 0.001), rectal temperature 60 min after birth (P < 0.01), type of presentation at birth (P < 0.05), presence of stillbirths (P < 0.001), and presence of mummified fetuses (P < 0.001). Small piglets (<0.98 kg) suffered a high hazard ratio (6.57; P < 0.001), with this variable being clearly lower for the rest of birth weight categories. Piglets that were small in relation to their siblings (relative birth weight within litter) also suffered an increased death risk, with a hazard ratio of 1.81 (P < 0.05), which was similar to animals with posterior presentations at birth (hazard ratio = 1.80; P < 0.05). Piglets with a rectal temperature lower than 35.4 degrees C 60 min after birth showed the highest hazard ratio (7.18; P < 0.01). Furthermore, the presence of mummified fetuses decreased the survivability of the remaining siblings, with a hazard ratio of 2.03 (P < 0.01), as did the presence of stillbirths (hazard ratio = 3.55; P < 0.001). The inclusion of the two random effects allowed us to estimate the mode of the joint posterior density of the sire variance (0.08) and the litter variance (1.98). The estimated heritability of preweaning survival reached a value of 0.03. We conclude that piglet survival involves several systematic influences related to birth weight, thermoregulatory ability, and injuries suffered during gestation and farrowing. The genetic variance was small compared with those generated by the common environment, for which the genetic improvement of piglet survival seems difficult.