Average Piglet Weight Research Articles

The effective use of Pietren breed at purebred and crossbred selection

The article highlights the problem of finding optimal variants of breeding process in a herd of pigs at purebred and crossbred selection. For this purpose, the control and two experimental groups were formed: ♀ Pietrain × ♂ Pietrain (control), ♀ (Pietrain × Large White) × ♂ Large White (first experimental group), ♀ (Pietrain × Durok) × ♂ Pitren (second experimental group). The analysis of the animals performance in these groups was carried out in 40, 30 and 35 parities, respectively. The research was conducted on the basis of PE «Maglevovany M.I.» in the Donetsk region. It has been established that the higher level of reproductive characteristics have sows of first experimental group, which have heredity of Large White breed, this breed is traditionally considered as a maternal form in cross-breeding schemes. For instance, their litter size at birth is higher than the same indicator in the control and second experimental group (plus 0,5, P<0,05, and 0,3 piglets, respectively); by the litter size at weaning at 28 days (plus 1,6, P<0,001, and 0,6 piglets); by the litter size at 2 months (plus 1,6, P<0,001, and 0,4 piglets). The highest piglet survival at the age of 2 months was in the litters, whose ancestor were boars of Pietrain breed (second experimental group) − plus 3,6 and 2,3 %, respectively, compered to purebred piglets of Pietrain breed and the first experimental group. For such complex indexes as the litter weight at weaning and litter weight at 2 months the first experimental group had an advantage of 18,1 kg (P<0,001) and 31,1 kg (P<0,001) over the control group (purebred Pietrain) and 5,4 kg and 7,6 kg − over the second experimental group. However, the average piglet weight of sows of second experimental group both at 28 days and at 2 months are equal to the average piglet weight of the same age of the first experimental group. The piglets, which are descendants of boars of meat breeds Duroc and Pietrain show a tendency to the faster growth even in an early age. The avarage live weight of pigs of the second experimental group at the age of 100 days and 7 months is higher compared to avarage live weight of pigs of the same age of the control and the first experimental groups – plus 8,5–21,7 kg (P<0,01 for the second experimental group) and 4,4–13,5 kg (P<0,001 for the second experimental group), respectively. At the age of 100 days, the maximum average daily gain was obtained in the second experimental group with an advantage of 190 g (P<0,001) compared to control group and 115 g (P<0,001) compared to the first experimental group. It is obvious that hybrids with the faster growth, which were obtained through crossbreeding ♀ (Pietrain × Duroc) × ♂ Pietrain reach a live weight of 100 kg in a shorter period: they need less time needed to reach 100 kg of live weight – 32 days less (P<0,001 ) compared to purebred animals of Pietrain breed (control group) and 18 days less (P<0,001) compared to hybrids ♀ (Pietrain × Large White) × ♂ Large White (the first control group). By such an indicator as the fat thickness the hybrids of the second experimental group dominate by purebred pigs of the same age of the control group (minus 0,2 mm), that characterize the low ability of meat breed for getting fat. The fat thickness of hybrids of the second experimental group was less by 0,9 mm (P<0,001) compared to the pigs of the first experimental group. Thus, in this herd in order to improve the reproductive qualities of sows, it is suggested to use the crossbreeding scheme ♀ (Pietrain × Large White) × ♂ Large White and to improve the fattening qualities of young animals the optimal is scheme of crossbreeding ♀ (Pietrain × Duroc) × ♂ Pietrain. Key words: pigs, Pietrain, Large White, Duroc, purebred and crossbred selection, reproductive and fattening qualities.

Alternatives to antibiotics in diets of weaned piglets

ABSTRACT: This experiment was conducted to evaluate the effect of growth promoter additives an alternative to antibiotics on performance, intestinal morphology and on microbiota of 21-to-35-day-old piglets. A total of 160 commercial crossbred piglets (males and females) with initial weight of 6.10±0.709kg were allotted in a completely randomized design with five treatments: Basal diet - Negative Control (NC); Basal diet + antibiotic (PC); Basal diet + mannanoligosaccharides (MOS); Basal diet + organic acids (OA), Basal diet + mannanoligosacharides + organic acids (MOS+OA), eight replicates and four piglets per experimental unit. The inclusion of additives in the diets had no effect (P>0.05) on the final average weight of piglets. Similarly, no effects (P<0.05) were observed on average daily feed intake and on average daily weight gain. The feed conversion improved (P<0.01) with the inclusion of additives in the diets compared to piglets fed with the NC. There was no effect (P>0.05) of the dietary additives on intestinal morphology and microbiota composition (enterobacteria and lactobacilli). Use of antibiotics, prebiotics, organic acids or prebiotics associated with organic acids in the diet improves feed conversion of piglets from 21 to 35 days of age. The additives have no major effects on piglets’ intestinal morphology and microbiota.

Порівняння збереженості поросят та інтенсивності їх росту у період дорощування при різних способах подачі та видалення повітря

Порівняння збереженості поросят та інтенсивності їх росту у період дорощування при різних способах подачі та видалення повітря

Evaluation of Different Calcium Sources on the Performance of Highly Prolific Lactating Sows

Improvements in sow productivity have raised questions regarding dietary mineral recommendations. Current calcium (Ca) levels and/or Ca sources might not support milk requirements of the larger litter in the modern sow. Therefore, four hundred and eighty mixed parity sows of a high prolificacy genetic line were used to evaluate the impact of the calcium source on the performance of highly prolific lactating sows. Sows were distributed in a completely randomized experimental design among six treatments containing different levels of inorganic Ca (INO) and organic calcium carbon-amino-phospho-chelate (CQT) inclusion. The sows were allocated to one of the six treatments represented by increased replacement ratios between sources of calcium: 100% INO; 100% CQT; 80% INO and 20% CQT; 60% INO and 40% CQT; 40% INO and 60% CQT; 20% INO and 80% CQT. Farrowing duration was not influenced (P>0.10) by the treatments, and averaged 185 minutes. Average daily voluntary feed intake did not differ (P>0.10) between treatments (5.54 kg d-1 on average). The lactation BW, backfat losses and chemical composition of body weight loss was not influenced (P>0.10) by the treatments. Litter size and average piglet weight at birth were not influenced (P>0.10) by the treatments (13.7 and 1.26 kg, on average). Litter weight gain, litter size and average piglet weight at weaning were also not influenced (P>0.10) by the treatments. The Treatments did not influence (P>0.10) estimated daily milk yield; which averaged 11.41 kg d-1. The treatments tended to influence (P 0.10) by treatments during lactation and averaged 1.38 mmol/L and 14.62 pg/ml, respectively. In conclusion, this experiment demonstrated that in diets for lactating sows an inorganic Ca source can be fully replaced by a more available Ca source (i.e., calcium carbon-amino-phospho-chelate), without negatively impacting the productive and reproductive performance of these animals or the performance of their litters.

Etude Préliminaire De La Valorisation Des Tourteaux D’hévéa, D’anacarde Et De Pourghère Chez Les Porcs Durant La Gestation Et La Lactation

The enhancement the cake of cashew kernels downgraded (Anacardium occidentale) (TA), the detoxified cake of kernels rubber (Hevea brasiliensis) (TH) and jatropha (Jatropha curcas) (TJ) in pig feed, was study on 21 pregnant gilts (73.4±8.1 kg). These females randomly distributed by group of three, received control diet (RT) and six other diets containing 7.5% or 15% of TA (RTA7.5 and RTA15), 7.5% or 15% of TH (RTH7.5 and RTH15) or 7.5% or 15% of TJ (RTJ7.5 and RTJ15). During the trial of 152 days, gilts under RTJ15 regime and two gilts under RTJ7.5 regime were withdrawn after respectively 14 and 21 days’ supply due to a persistent diarrhea. The latest gilt under RTJ7.5 had aborted at 90 days of gestation. No significant difference was observed on the average litter size (9.2 piglets). The average weight of piglets at birth ranged from 1.3±0.2 kg (RTA15) and 1.1±0.2 kg (RTH7.5), while the average daily gain (ADG) of

Changes in body weight and fatness of sows during reproductive activity depending on LEPR and MC4R genes polymorphism

The use of genetic markers in selection of maternal breed gilts for reduced feed intake and fatness of pigs, may impact on their reproductive performance in subsequent breeding. The objective of the study was to analyse changes, over three consecutive lactations, in condition (body weight and fatness) and reproductive performance of Polish Large White (PLW) and Polish Landrace (PL) sows of known genotype at leptin receptor (LEPR) and melanocortin 4 receptor (MC4R) loci. The study involved 58 PLW and 65 PL gilts. Gilts and subsequently sows were monitored for body weight (BW) and backfat thickness (P2) over three reproductive cycles, and their litters were analysed for the number and body weight of the piglets. A total of 168 litters of PLW pigs and 186 litters of PL pigs were evaluated. It is concluded that over the three reproductive cycles, PLW sows exhibited higher weight gains and lower fatness compared to PL sows. The interaction between LEPR and MC4R genes had a significant effect on changes in body weight of the gilts, subsequently on changes in the condition of sows (BW and P2) during consecutive reproductive cycles, and on the average weight of piglets born. Heterozygous sows of LEPRAB/MC4RAG genotype were characterized during that time by the highest weight gains and backfat thickness at P2, and their the piglets born had low birth weight. Over the three reproductive cycles, sows of LEPRAA/MC4RGG and LEPRAB/MC4RGG genotypes produced piglets with significantly higher birth weight compared to sows of LEPRAB/MC4RAG, LEPRBB/MC4RAA and LEPRBB/MC4RGG genotypes.

An automatic splitting method for the adhesive piglets’ gray scale image based on the ellipse shape feature

The average weight of piglets in lactation can be monitored automatically by piglets’ average weight monitoring systems which are designed based on wireless multimedia sensor networks. Piglets counting in an automatic manner for piglets images is the foundation of these systems. Adhesive piglets may exist in an image due to the social character of piglets, which challenges the image splitting and automatic piglets counting.This paper proposes a segmentation algorithm for adhesive piglets images based on ellipse fitting method. Firstly, ellipse fitting is implemented for a large number of images which have one piglet. Parameters range of ellipses fitted by images with a single piglet on different age is extracted. Secondly, contours of connected components in an adhesive piglets image are extracted. Each contour is segmented based on concave points. Ellipse fitting is implemented for each contour segment. Finally, 5 rules for ellipse merging are put forwarded, which are used to merge anomalous ellipses. After ellipse merging, the number of ellipses equals the number of piglets. The proposed algorithm is applied to adhesive piglets images in Matlab R2012b and the experimental results show that the counting accuracy exceeds 86% when the number of piglets is less than 7. The algorithm provides the foundation for the piglets’ average weight monitoring systems.

Genetic and environmental factors affecting reproductive traits in sows in an outdoor production system

The aim of this study was to characterize the genetic (crossbreeding and additive genetic) and environmental factors affecting reproduction of sows on an outdoor production system. Data from the Experimental Swine Unit of Facultad de Agronomía, Progreso, Uruguay, were used. The breeding herd included purebred Pampa Rocha (P) and Duroc (D), as well as hybrid (H: P×D and D×P) sows. Pampa Rocha is considered the only local swine breed of Uruguay. The dataset contained 1309 litter records from 197 sows (136 P, 22 D and 39 H) collected from 1997 to 2011. Feeding was based on grazing, restricting the use of concentrate to the breeding herd. The variables analysed were: number of piglets born alive (PBA), average piglet weight of the litter at birth (ABW), number of piglets weaned (PW), average piglet weight of the litter at weaning (AWW), survival from birth to weaning (S) and weaning-to-conception interval (WCI). The following fixed factors were included in the final model: year of farrowing, time of the year (month or season, depending on the variable analysed), inbreeding of the sow, parity number, weaning age, direct breed effects, individual heterosis, repeated measures on the sow (used to estimate the permanent environment effect), and the animal random effect. Duroc sows produced 1.1 more PBA (p=0.03) than P sows. Significant heterosis effects were found for PBA (0.88 piglets, p=0.009) and for PW (0.72 piglets, p=0.03). Hybrid sows produced 1.43 and 1.15 piglets more than P sows, and 0.33 and 0.29 piglets more than D sows, born alive and weaned, respectively. No differences in other variables between genotypes were found. Heritability values (SE) were 0.13 (0.06) for PBA, 0.31 (0.08) for ABW, 0.14 (0.06) for PW, 0.17 (0.02) for AWW, 0.10 (0.01) for S and 0.08 (0.03) for WCI. Winter and spring farrowings resulted in heavier piglets at birth (p<0.001) and at weaning (p<0.01), but no effect on PBA, P and S was observed. Weaning-to-conception interval was greater in summer months (p<0.001). The results suggest seasonal reproductive behaviour. The local breed (P) compared well with a conventional one (D). Furthermore, the crossbred dam appeared attractive due to heterosis in litter traits.

Effect of Weaning Age on growth Performance and Feed Conversion Efficiency of Large White Yorkshire (LWY) Piglets under Intensive System of Management in Mizoram

The study was for assessment of weaning age on growth performance and feed conversion efficiency of LWY piglets under intensive system of management in Mizoram. The study was conducted on piglets from twelve LWY sows. The sows were selected based on parity, sire mated, litter size and weight, and divided into three homogenized groups with 4 sows in each group (T1, T2 and T3). Piglets of T1 group were weaned at 28 days, of T2 at 35 days and of T3 at 42 days of age. The weaned piglets were reared up to 77 th days of age. The animals were reared under intensive system of management following standard feeding and managemental norms. The average body weight of piglets weaned at 28 th and 35 th day of age were found to be significantly (P<0.05) higher than the body weights of piglets weaned at 42 nd day of age. The body weight gain of the early weaned piglets was observed to be higher than the late weaned piglets. The average total body weight gain at 77 th day of age was found to be 19.11, 17.72 and 16.60 kg, respectively for piglets weaned at 28 th , 35 th and 42 nd day age. Feed conversion efficiency at 77 th day of age was recorded as 2.32±0.16, 2.44±0.19 and 2.48±0.07 indicated that early weaned piglets performed well under the same feeding and managemental situation. From the findings of the study, it was concluded that weaning at 28 th day

Desempeño reproductivo de cerdas primerizas suplementadas con riboflavina durante la gestación

Para evaluar los efectos en el tamaño de lechigada y la expresión del factor de crecimiento endotelial vascular (VEGF; por sus siglas en inglés) y de la uteroferrlna, cerdas primerizas cruzadas (n = 24) se suplementaron con 0 o 60 mg de riboflavina diariamente durante toda la gestación. El tamaño de la lechigada y el peso individual de las crías se determinó al nacer y al destete. Se colectaron muestras de placenta al momento del parto para determinar la expresión relativa del VEGF y de la uteroferrina. Las cerdas suplementadas y no suplementadas parieron 11.2 ± 0.6 y 8.2 ± 0.6 cerditos totales, respectivamente (P &lt; 0.004). Hubo diferencias análogas en el número de cerditos nacidos vivos de 10.5 ± 0.6 contra 8.1 ± 0.6 (P &lt; 0.01) y en el número total de cerditos destetados (9.41 ± 0.6 y 7.5 ± 0.6, P &lt; 0.05). Se encontró diferencia entre los tratamientos para el peso total de la lechigada al nacer pero no al destete. La expresión relativa del VEGF fue mayor (P &lt; 0.07) en la placenta de cerdas suplementadas con riboflavina que en las controles, pero los tratamientos no difirieron en la expresión relativa de la uteroferrina. Los resultados presentes indican que la suplementación con 60 mg diarios de riboflavina a cerdas primerizas durante la gestación puede incrementar el tamaño de la lechigada, quizás mediado por una mejor vascularización de la placenta y por consiguiente mejorando la supervivencia del embrión/feto.

Methods to Supply Chilled Drinking Water for Lactating Sows During High Ambient Temperatures

The aim of this study was to determine an effective method to supply chilled water (CW) for lactating sows during high ambient temperatures. One hundred twenty multiparous sows (Yorkshire × Landrace; parity range: 2 to 5) and their litters [Duroc × (Yorkshire × Landrace)] were divided into four groups of 30 sows each. Each group was used to investigate the effects of the four water supplying methods (Control: free access to unchilled water at 22°C; FACW: free access to chilled drinking water at 15°C; RACW: restricted access to chilled water at 15°C; and RACW+SS: restricted access to chilled water at 15°C + sound stimulus) under farm conditions with ambient temperatures above 25°C. Sows in the FACW, RACW, and RACW+SS groups ate and drank more than the sows in the control group that received water at 22°C (P<0.01). Respiration rate and rectal temperature were lower in sows in the CW groups than in the control group (P<0.01). Litter size on 0 day post-partum and at weaning did not differ among treatments, whereas average weaning weight and average daily gain (ADG) of piglets from the FACW, RACW, and RACW+SS groups were higher than those in the control group (P<0.01). There were no differences in the measured variables among treatment groups that received water chilled to 15°C (P>0.05). These results suggest that the optimal CW supplying method, from an energy viewpoint, may be RACW.

Does a Boar's Season of Birth Determine Semen Parameters and Reproductive Performance?

This article studies the effect of a boar's birth season and breed on semen parameters and its further reproductive performance. Research material consisted of 72 boars from three breeds (24 Polish Large White PLW, 24 Polish Landrace PL, 24 Duroc × Pietrain D × P). During the whole period of the study, selected semen parameters were analysed: semen volume, spermatozoa concentration, total number of spermatozoa, total number of motile spermatozoa, number of insemination doses and also reproductive indicators: farrowing rate, total born litter size, total number of piglets born live and still, and average piglet weight. Boars born in the winter and summer months demonstrated the highest spermatozoa concentrations (383.25 and 392.37 × 10(6)/ml), total number of spermatozoa (91.75 and 93.21 × 10(9)), total number of motile spermatozoa (76.10 and 77.99 × 10(9)) and number of insemination doses (24.53 and 24.89; p ≤ 0.01). Statistically lower values for these parameters were observed for boars born in the spring and especially in autumn (p ≤ 0.01). The significant impact of birth season on farrowing rate (p ≤ 0.05) and average piglet weight (p ≤ 0.05) was confirmed for PLW boars. For the PL breed, only the total number of piglets born live was proven to be significantly affected (p ≤ 0.05). No impact of birth season was shown on semen quality or reproductive performance for D × P boars. In our study, we showed that the birth season of a boar had a more impact on the level of semen parameters, and less on the reproductive performance indicators. The results indicated that both the quality of semen and reproductive performance varied in terms of the study factors, as well as between individual breeds of boars involved in the experiment.

Índices produtivos de fêmeas suínas alimentadas com dietas de gestação e lactação suplementadas com óleos essenciais de orégano e alecrim: avaliação de leitegadas

Este estudo avaliou os índices produtivos de matrizes suínas alimentadas com dietas contendo uma mescla líquida de óleos essenciais. Foram utilizadas 250 matrizes de ordens de parto (OP) entre um a oito, com duas dietas experimentais na gestação e duas na lactação (dietas controle e com 200ppm de óleos essenciais). O delineamento experimental foi o de blocos ao acaso, em um arranjo fatorial 2x2 (tratamentos na gestação e na lactação) com as matrizes e leitegadas como unidade experimental. O peso vivo médio da leitegada ao desmame e o número de desmamados foram 8,0% e 3,8% superiores (P&lt;0,05), respectivamente, para os leitões filhos de matrizes suplementadas com óleos essenciais. A temperatura corporal das fêmeas do controle e OP cinco, avaliadas no período pré-parto e durante o parto, foi 4,4% e 3,5% superiores (P&lt;0,05) aos óleos essenciais, respectivamente. A adição de óleos essenciais na dieta de matrizes no final de gestação e no início da lactação aumentou o número de leitões desmamados e o peso de leitegada. As fêmeas suplementadas com óleos essenciais não apresentaram temperatura e sinais clínicos condizentes com disgalactia.

Effects of cross-fostering within 24 h after birth on pre-weaning behaviour, growth performance and survival rate of biological and adopted piglets

Cross-fostering is the transference of piglets to equalise litter size according to the birth weight. In many commercial farms piglets are usually grouped in litters with 100% adopted piglets. The aim of the experiment was to assess the behaviour of piglets during the suckling period as well as to assess their performance and mortality rate up to weaning in litters with different composition in terms of adopted and biological piglets. Three treatments were studied: 100B (100% biological piglets, n=13), 50B50A (50% biological piglets and 50% adopted piglets, n=13) and 100A (100% adopted piglets, n=13). All litters were standardised to eleven piglets on average within 20.1±0.4h (14.3–24.7h) of birth. The behaviour of piglets was recorded during four consecutive sucklings for four days (days 1, 2, 4 and 6 after farrowing, considering day 1 as the cross-fostering day). The observations were performed at two time periods: TP1 (from release of piglets out of creep box until milk letdown) and TP2 (from the end of milk letdown up to 15min later). Piglets were weighed at days 1, 4, 7, 10, 13 and 16. There were no differences (P>0.05) among the treatments in the following behavioural variables: percentage of missed nursing episodes; number of fights for teats and percentage of piglets involved in fights at TP1; percentage of piglets vocalising at TP1 and at TP2; number of fights per piglet elsewhere in the cage and percentage of piglets involved in these fights; number of instances of playful behaviour per piglet and percentage of piglets involved in it. At TP2 of day 1, 100B piglets displayed a lower number (P<0.05) of fights for teat (0.9 vs. 1.6 vs. 1.4 for 100B, 100A and 50B50A, respectively) and tended to have a lower percentage (P<0.07) of piglets involved in these fights than 100A (49.6%, 67.2% and 64.9% for 100B, 100A and 50B50A, respectively). Nutritive nursing episodes (overall medians of 4.0, 3.0, 4.0 and 4.0 for days 1, 2, 4 and 6, respectively), survival rate (overall 97.2%) and average weight of piglets (1983g, 2650g, 3411g, 4207g and 5047g for days 4, 7, 10, 13 and 16, respectively) were similar (P>0.05) among treatments. Cross-fostering performed on average at 20h after birth has no adverse effects on survival and growth performance of adopted piglets.

Parenteral administration of vitamins A, D and E on the oxidative metabolism and function of polymorphonuclear leukocytes in swine

The weaning period of piglets is characterized by physiological alterations, such as decreased weight gain, increased reactive oxygen species (ROS) and increased serum cortisol levels with possible effects on the immune response. The effect of parenteral administration of vitamins A, D and E on production performance, oxidative metabolism, and the function of polymorphonuclear leukocytes (PMNLs) was assessed in piglets during the weaning period. The sample was comprised of 20 male piglets that were given an injectable ADE vitamin combination (135,000 IU vitamin A, 40,000 IU vitamin D and 40mg vitamin E/ animal) at 20 and 40 days of age. Weight gain, concentration of reduced glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD) and the microbicidal and phagocytic activity of PMNLs were assessed. No difference was observed in the average piglet weight during the study; however, a greater percentage of weight gain was observed after weaning in the treated group. The concentrations of GSH and SOD did not differ between groups, although lipid peroxidation was greater in the control group at 60 days of age. The investigated variables of oxidative metabolism were correlated as follows: -0.41 for GSH and MDA, -0.54 for GSH and SOD and 0.34 for MDA and SOD. The intensity of intracellular ROS production, the percentage of ROS-producing PMNLs and the intensity of phagocytosis by PMNLs did not differ between treatment groups. Administration of the injectable ADE combination improved the percentage of weight gain between 20 and 40 days of age, decreased oxidative stress at 60 days of age and did not influence the function of PMNLs in piglets.

The effect of the body condition of late pregnant sows on fat reserves at farrowing and weaning and on litter performance

Abstract. The objective of this study was to determine the effect of the body condition of late pregnant sows on fat reserves at farrowing and weaning, including the scale of the relevant changes in that period, and on the reproductive performance of sows and the results of piglet rearing. The experiment involved 97 hybrid sows (Polish Large White × Polish Landrace [PLW×PL]) divided into two groups, according to backfat thickness: I – (P2+P4)/2&gt;20 mm (10 primiparous, 36 multiparous) and II – (P2+P4)/2≤20 mm (19 primiparous, 32 multiparous). It was carried out between pregnancy day 104 and weaning after 21 days of lactation. During late pregnancy, at weaning and at the end of lactation, the body weight of sows, fatness (points P1, P2, P3, P4) and longissimus muscle depth at point P4M were determined. Feed consumption during lactation, reproductive performance traits and the results of piglet rearing were also analyzed. Higher backfat thickness percentages and body weight noted in group I sows vs. group II sows (P≤0.001) during late pregnancy were maintained at farrowing and weaning. At weaning, the values of longissimus muscle depth were significantly (P≤0.001) higher in group II than in group I. The level of changes in fat reserves differed between late pregnancy and farrowing for P4 (P≤0.01) and (P2+P4)/2 (P≤0.001); fat reserve loss was noted in group I, while an increase in adipose tissue was observed in group II. Body weight losses (%) during late pregnancy and at weaning were non-significant in sows of both groups. Based on feed consumption levels, group I sows were characterized by a lower appetite during lactation than group II sows. A regular trend in feed intake was noted in lactating sows of both groups: feed consumption increased in week 2, compared with week 1, while a decrease was noted in week 3 in comparison with week 2. Significant differences were reported in favour of group I vs. II (P≤0.05) as regards the piglets stillborn, litter weight at weaning, the average piglet weight at weaning and placental weight. Multiparous sows as compared to primiparous sows were characterized by significantly (P≤0.05) larger total number of piglets born and the number of piglets born alive. The difference in the litter weight at birth was found to be highly significant (P≤0.01).

Genetic analysis of reproductive performance in Landrace sows and its correlation to piglet growth

The aim of this study was to investigate the reproductive performance of sows, including the interval from weaning to service after 1st litter and litter size in the following (2nd) parity, as well as the direct and maternal genetic effects of piglet growth on these reproduction traits. Data on 15 946 Norwegian Landrace sows' 1st and 2nd parity, and on 106,962 piglets born in 11,323 1st parity litters were included in the analyses. In total, five traits were analysed. Weaning-to-service interval was based on a 1- to 7-day interval (WSI7) or a transformed 1- to 50-day interval (WSI50). A third reproduction trait was total number of piglets born in 2nd parity (NBTnext). Piglet weight was included in the analyses, either as average piglet weight in the litter at 3 weeks of age (meanW3) or as individual piglet weight gain during the first 3 weeks of life (IWG03). Genetic parameters were estimated with animal models, including both direct and maternal effects for IWG03. Heritability estimates for WSI7, WSI50 and NBTnext were 0.08, 0.03 and 0.09 respectively. For meanW3, the heritability estimate was 0.21. For IWG03, the direct and maternal heritability estimates were 0.15 and 0.10 respectively. Negative and unfavourable genetic correlations were estimated between meanW3 and NBTnext ( r g = − 0.37), and between IWG03 maternal and NBTnext ( r g = − 0.39). The ability to raise fast growing, heavy piglets seems to have an unfavorable effect on total number born in next litter but not on the weaning-to-service interval.

A whole genome scan to detect quantitative trait loci for gestation length and sow maternal ability related traits in a White Duroc × Erhualian F2 resource population

Gestation length and maternal ability are important to improve the sow reproduction efficiency and their offspring survival. To map quantitative trait loci (QTL) for gestation length and maternal ability related traits including piglet survival rate and average body weight of piglets at weaning, more than 200 F2 sows from a White Duroc × Erhualian resource population were phenotyped. A genome-wide scan was performed with 194 microsatellite markers covering the whole pig genome. QTL analysis was carried out using a composite regression interval mapping method via QTL express. The results showed that total number of born piglets was significantly correlated with gestation length (r = −0.13, P < 0.05). Three QTL were detected on pig chromosome (SSC)2, 8 and 12 for gestation length. The QTL on SSC2 achieved the 5% genome-wide significant level and the QTL on SSC8 was consistent with previous reports. Four suggestive QTL were identified for maternal ability related traits including 1 QTL for survival rate of piglets at weaning on SSC8, 3 QTL for average body weight of piglet at weaning on SSC3, 11 and 13.

Porcas lactantes alimentadas com dietas contendo silagem de grãos úmidos de milho e ácidos orgânicos

Um experimento foi realizado para avaliar o desempenho de porcas lactantes e suas leitegadas alimentadas com dietas contendo silagem de grãos úmidos de milho com ou sem ácidos orgânicos. Foram utilizadas 15 porcas híbridas em um delineamento de blocos ao acaso com três tratamentos (dieta controle, dieta com adição de 0,5% de ácido benzóico e dieta com adição de 0,5% de ácido fumárico) com cinco repetições cada. As dietas elaboradas com silagem de grãos úmidos de milho com ácido benzóico ou ácido fumárico não alteraram (P&gt;0,05) a espessura de toucinho e o consumo médio diário de ração. O ganho médio diário (0,22kg) e o peso vivo médio ao desmame (6,2kg) dos leitões não diferiram (P&gt;0,05) entre os tratamentos. A adição dos ácidos fumárico e benzóico nas dietas elaboradas com silagem de grãos úmidos de milho não altera os desempenhos de porcas lactantes e de suas leitegadas.

Effects of intermittent suckling on the performance and digestive efficiency of Iberian piglets weaned at 35 days of age

During two consecutive replicates Iberian sows ( n = 20) were subjected either to a conventional lactation (C) or intermittent suckling (IS). Piglets in the C treatment had free access to the dam. Piglets on IS treatment were separated from the sow during 6 h on days 29 and 30, 8 h on days 31 and 32, and 10 h on days 33 and 34. Litters on both treatments were weaned at 35 days of age and offered a starter diet until day 60 of age. The apparent digestibility (ApD) of nutrients and gross energy (GE) of the post-weaning diet was measured using Cr 2O 3 as external indigestible marker. Litters on IS tended to increase solid feed intake during the milk restriction (125 ± 12 vs. 70 ± 19 g piglet − 1 day − 1 ; P = 0.08). Feed intake was improved by IS during the second week post-weaning (676 ± 17 vs. 497 ± 12 g piglet − 1 day − 1 , P < 0.01), but differences were totally offset after the 7th week of age. Differences in average growth rate of litters on C and IS treatments did not attain statistical significance during the period of restriction and in the first week post-weaning. Litters on IS showed increased growth rate during the second week post-weaning (422 ± 31 vs. 289 ± 33 g piglet − 1 day − 1 ; P = 0.01), but slower daily gains from the 3rd week post-weaning to 60 day of age than litters on C treatment (371 ± 14 vs. 432 ± 15 g piglet − 1 day − 1 ; P < 0.05). Nevertheless, neither at weaning nor at 60 days of age average body weight of piglets differed between treatments (7.71 ± 0.31 vs. 7.94 ± 0.30 kg for C and IS, at 35 days of age, 15.62 ± 0.65 vs. 16.20 ± 0.62 kg, at day 60). The apparent digestibility of nutrients of the starter diet offered after weaning remained unaffected by the treatment, except for a trend for higher ApD of GE for the piglets on IS treatment ( P = 0.08). ApD for CP and GE was 78.1 ± 0.6 and 78.8 ± 0.3%, respectively. No significant differences in the proportions of total viscera and gastrointestinal tract to empty body weight (EBW) were observed between C and IS piglets at weaning and 60 d of age. In conclusion, the increase in feed intake observed prior and early after weaning as a consequence of intermittent suckling during the last week of 35 d lactation had no effect on nutrient digestibility measured at two weeks after weaning and failed on improving Iberian piglet performance.