Effect of dietary regime and group structure on pig performance and the variation in weight and growth rate from weaning to 20 weeks of age

Posted in: Production by admin on August 4, 2011 | No Comments

This study aimed to improve lifetime pig performance and reduce variation in growth rate between pigs using managerial and nutritional practices. The experiment (2×2×2 factorial) compared uniform and mixed weight grouping (SD of weight in group at weaning 0.7 kg and 1.6 kg respectively), offering pigs a high (12 kg) or low (6 kg) allowance of starter diets post weaning and either a special (DE 14.5 MJ/kg, total lysine 11 g/kg) or normal (DE 13.5 MJ/kg, total lysine 9.5 g/kg) finishing diet. Over six time replicates, 960 pigs (Landrace×Large White) were randomly allocated at weaning (28±2 days of age) into groups of 20 according to weight and sex and these groups were split at 10 weeks of age (transfer to finishing accommodation) into two groups of 10. Finishing diet was offered from 11 weeks of age. The FCR of pigs (wean–7 weeks of age) was significantly improved when a high allowance of starter diets was offered (1.25) compared with a low allowance (1.34). However, between 7 and 10 weeks of age a high allowance of starter diets only improved the FCR of pigs in uniform groups. A special finishing diet improved the ADG of pigs during finish (11–20 weeks of age) (860 g/day) compared with a normal finishing diet (827 g/day). The coefficient of variation (CV) of weight at 10 and 15 weeks of age was significantly lower for pigs in uniform weight groups compared with that of pigs in mixed weight groups. A three-way interaction was observed on the CV of ADG (weaning–20 weeks of age) and FCR (11–20 weeks of age). The lowest CV of ADG (weaning—20 weeks of age) and lowest FCR (11–20 weeks of age) were achieved when uniform grouped pigs were offered a high allowance of starter diets post weaning and a special finishing diet (0.117 and 2.43 respectively) whereas the highest values were observed when mixed weight groups of pigs were offered a low allowance of starter diets post weaning and a normal finishing diet (0.162 and 2.70 respectively). In conclusion, although uniform grouping appears to aid the reduction in slaughter weight variation and improve FCR, its effect is dependent on dietary regime. Overall, from weaning to 20 weeks of age, uniformly grouped pigs offered a high allowance of starter diets post weaning and a special finishing diet had a low CV of ADG and the most efficient FCR.

For more information the full article can be found at http://www.journals.elsevierhealth.com/periodicals/livsci

The performance response of pigs of different wean weights to ‘high’ or ‘low’ input dietary regimes between weaning and 20 weeks of age

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In a 3×2×2 factorial design, this study aimed to compare the lifetime performance of light (average of 7.1 kg), medium (average of 8.9 kg) or heavy (average of 10.4 kg) wean weight pigs when offered either a high (12 kg/pig) or low (6 kg/pig) allowance of starter diets post weaning and either a normal (DE 13.5 MJ/kg, total lysine 9.5 g/kg) or special (DE 14.5 MJ/kg, and total lysine 11 g/kg) finishing diet from 11 weeks of age. Over six time replicates, 720 pigs (Landrace×Large White) were randomly allocated at weaning (28±2 days of age), into groups of 20 which were balanced for sex. These groups were split into two groups of ten at 10 weeks of age (transferred to finishing accommodation). The 20-week weight (88.9 kg), ADG (702 g/day) and ADFI (1841 g/day) between wean and 20 weeks of age was greater for heavy weight pigs (Pb0.001) than for light weight pigs (82.2 kg, 692 and 1715 g/day respectively). However, on a per kg of body weight basis the feed intake/kg (39 g/day/kg) and growth rate/kg (14.8 g/day/kg) of light weight pigs was greater than that of heavy weight pigs (37.4 and 14.4 g/day/kg respectively). A high allowance of starter diets increased 10-week weight, ADG and reduced ADFI and FCR between weaning and 10 weeks of age compared with that of pigs offered a low allowance. There were significant interactions between starter diet allowance and finishing diet on finishing pig performance. The 20-week weight and ADG (11 to 20 weeks) of pigs offered a high allowance of starter diets increased when they were offered a special finishing diet compared with a normal finishing diet. However, that of pigs offered a low allowance of starter diets was lowered when they were offered a special finishing diet compared with a normal finishing diet. On the other hand, the ADFI of pigs offered a high allowance of starter diets was similar whether they were offered a normal (1977 g/day) or special (1976 g/day) finishing diet, whereas those offered a low allowance of starter diets had an increased ADFI (2091 g/day) when offered a normal finishing diet compared with a special finishing diet (1903 g/day). In conclusion, when the ‘nutrient density’ of the diet changed, in particular towards lower supplies, pig weight and growth rate were poorer. In addition light weight pigs at weaning were found to convert feed as efficiently as heavy weight pigs throughout their lifetime. Furthermore, their lifetime growth rate and feed intake on a ‘per kg of body weight’ basis was higher than that of heavy pigs.

For more information the full article can be found at http://www.journals.elsevierhealth.com/periodicals/livsci

The effects of housing system and feeding level on the joint-specific prevalence of osteochondrosis in fattening pigs

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Osteochondrosis (OC) is seen as the main cause of leg weakness in pigs, leading to welfare problems and economic losses. Environmental factors in pig husbandry, such as the housing system and feeding strategy are expected to influence the prevalence of OC. Therefore, this study investigated the effects of housing system and feeding strategy on the prevalence and severity of OC. In the experiment 345 pigs were used. At an age of 69 days intact boars and gilts were separated and assigned to groups of five or six individuals. A two by two factorial design of housing system and feeding strategy was applied. The housing system was either a conventional concrete floor partial slatted, or a deep litter floor with extra space allowance. The feeding strategy was either ad libitum or restricted to 80% of ad libitum. Pigs were slaughtered at the age of 161–176 days. In total, five joints of the left front and hind limbs were macroscopically assessed for OC on a five-point scale, ranged from no OC through (semi-)loose cartilage fragments. The prevalence of OC in the experimental population was 41.4%, and 12.4% of the individuals had severe lesions. The tarsocrural joint was most affected (30.2%) by OC. OC scores between the different joints were not correlated. Medial sections of joints were most affected (63– 100%). Boars were more affected than gilts in the elbow joint. Conventionally housed pigs were more affected than deep litter housed pigs. Ad libitum fed pigs had more OC than restrictedly fed pigs. OC was most prevalent with 57.5% in the pigs on the conventional floor with ad libitum feeding. OC was least prevalent with 33.7% in pigs kept in deep litter housing with restricted feeding. The sex, housing system and feeding strategy did not affect OC in the femoropatellar, metacarpophalangeal, and metatarsophalangeal joints. Our results demonstrate that the OC prevalence can be reduced by applying deep litter floors with extra space allowance and/or restricted feeding in fattening pigs.

For more information the full article can be found at http://www.journals.elsevierhealth.com/periodicals/livsci

Management routines at the time of farrowing—effects on teat success and postnatal piglet mortality from loose housed sows

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The aim of this experiment was to study the effects of six different management routines at the time of farrowing on latency to first suckle, heat loss, weight gain and postnatal mortality. A total of 872 piglets from 67 loose housed sows in a commercial pig unit were subjected to one of six different management routines: control (CON n=14), no treatment; (CREEP n=13), placed in creep area; (UDDER n=10), placed at the udder; (DRY n=10), dried and placed back where found; (DRYCREEP n=9), dried and placed in creep area; and (DRYUDD n=11), dried and placed at the udder. The latency from birth to first suckle, rectal temperature at birth, 2 hours and 24 hours were measured for each piglet, in addition to weight at birth, 2 hours and 24 hours. Latency from birth to first suckle was shortest for piglets in the DRYUDD treatment, followed by the UDDER treatment. More live born piglets died in the UDDER treatment compared to the other treatments, but there were no other differences between the treatments with regards to postnatal mortality. There was a significant interaction between treatment and batch, with a significantly lower postnatal mortality in the DRYUDD treatment than CON in batch 2, but not in batch 1 and 3. Large litter sizes resulted in a higher postnatal mortality in all treatments, and tended to reduce latency to suckle. In conclusion, drying the piglets after birth and placing them at the udder resulted in reduced postnatal mortality in batch 2, but not in the other two batches. Despite having the largest mean litter size of the treatments, less than 10% of the piglets in DRYUDD died, which is remarkably low for loose housed sows. Regardless of treatment, several piglet-related factors were found to be highly important for postnatal mortality, such as the number of functional teats per piglet, birth weight, the latency from birth to first suckle, and rectal temperature at 2 hours after birth.

Effect of pen mates on growth, backfat depth, and longissimus muscle area of swine

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Records on final BW (kg), backfat depth (cm), and LM area (cm2) of pigs from a University of Nebraska Large White/Landrace composite population were analyzed to estimate the effects of pen mates. Measurements were at approximately 180 d of age for 3,524 pigs in 351 pens (9 to 11 pigs per pen) farrowed from 1999 to 2005. The area of each pen was 8.13 m2. The full model (M1) included the fixed effects of contemporary group, sex, line, and the covariates of age and inbreeding coefficient, and included random direct genetic, genetic pen-mate, permanent environmental, pen, litter, and residual effects. A derivativefree algorithm was used to obtain REML estimates of variance components for final BW adjusted to 180 d of age with M1 and 7 reduced models, and with 4 reduced models for the carcass traits. For final BW, likelihood ratio tests showed that M1 did not fit the data better than model 2 (permanent environmental effect omitted from M1) or model 3 (pen omitted from M1). Model 2 was not significantly (P > 0.05) better than model 3, which shows that variance attributable to pen effects and permanent environmental effects cannot be separated. Large sampling variances of estimates of the pen component of variance for models with pen-mate effects also indicate an inability to separate pen effects from the effects of pen mates. When pen-mate genetic effects were not in the model, estimates of components of variance and the fit of the data were the same for models 4 (included both permanent environmental and pen effects), 6 (included pen effects), and 7 (included permanent environmental effects), which shows that including both pen and permanent environmental effects was no better than including one or the other. Models 4, 6, and 7 were significantly better than model 8, which did not include pen-mate effects and pen effects, implying that pen effects are important. The estimate of pen variance with model 2 was approximately (number of pen mates − 1) times the estimate of variance of pen-mate permanent environmental effects with model 3. Patterns of estimates of variance components with models 2, 5, 6, and 8 for backfat depth and LM area were similar to those for final BW. Estimates of direct genetic variance and phenotypic variance were similar for all models. Estimates of heritability for direct genetic effects were approximately 0.40 for final BW, 0.45 for backfat depth, and 0.27 for LM area. Estimates of heritability for pen-mate genetic effects were 0.001 for the 3 traits for models including either pen or permanent environmental effects. Under the management conditions for this experiment, the conclusion is that the model for genetic evaluation should include litter effects and either pen effects or pen-mate permanent environmental effects and possibly genetic pen-mate effects, in general agreement with the results of studies of different populations at other locations.

For more information the full article can be found at http://jas.fass.org/

Estimates of genetic parameters among scale activity scores, growth, and fatness in pigs1,2

Posted in: Production, Welfare by admin on July 29, 2011 | No Comments

Genetic parameters for scale activity score (AS) were estimated from generations 5, 6, and 7 of a randomly selected, composite population composed of Duroc, Large White, and 2 sources of Landrace (n = 2,186). At approximately 156 d of age, pigs were weighed (BW) and ultrasound backfat measurements (BF1, BF2, and BF3) were done. While pigs were in the scale, an AS was assigned, which ranged from 1 (calm) to 5 (highly excited), where 58.1, 28.5, 8.9, 4.0, and 0.5% were scored as 1, 2, 3, 4, and 5, respectively. Statistical model effects were year-week of measurement, sex, covariates of age for AS and BW or BW for BF1, BF2, and BF3, and an animal direct genetic effect. A 5-trait linear mixed model was used. Estimated heritabilities were 0.23, 0.54, 0.56, 0.52, and 0.48 for AS, BW, BF1, BF2, and BF3, respectively. Estimated genetic correlations between AS and BW, AS and BF1, AS and BF2, and AS and BF3 were −0.38, −0.11, −0.12, and −0.16 respectively. Results indicated AS had a heritable genetic component and was genetically correlated with performance traits. Estimated genetic correlations between AS and backfat measurements adjusted to a common BW were negative, as was the genetic correlation of AS with BW. Therefore, selection for more docile animals would be expected to result in fatter, faster growing pigs.

For more information the full article can be found at http://jas.fass.org/

Maternal responses to daily maternal porcine somatotropin injections during early-mid pregnancy or early-late pregnancy in sows and gilts

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Piglet neonatal survival and postnatal growth and efficiency are positively related to birth weight. In gilts, daily maternal porcine ST (pST) injections from d 25 to 100 (term approximately 115 d), but not d 25 to 50, of pregnancy increase progeny birth weight. Daily maternal pST injections from d 25 to 50 increase fetal weight at d 50 in gilts and sows. We therefore hypothesized that daily pST injections from d 25 to 100, but not d 25 to 50, of pregnancy would increase birth weight similarly in both parities. Landrace × Large White gilts and sows were uninjected (controls) or were injected daily with pST (gilts: 2.5 mg/d; sows: 4.0 mg/d, each approximately 15 μg of pST/kg per day) from d 25 to 50 or 100 of pregnancy. Litter size and BW were recorded at birth, midlactation, and weaning. Dams were followed through the subsequent mating and pregnancy. Maternal pST injections from d 25 to 100, but not d 25 to 50, increased mean piglet birth weight by 11.6% in sows and by 5.6% in gilts. Both pST treatments decreased litter size by approximately 0.6 live-born piglets. In sows, maternal pST treatment from d 25 to 100 increased culls at weaning. In remated dams, prior treatments did not affect the weaning-remating interval, conception rate, or subsequent litter size. Greater pST-induced birth weight increases in sows than in gilts may mean that underlying metabolic or placental mechanisms for pST action are constrained by maternal competition for nutrients in rapidly growing gilts.

For more information the full article can be found at http://jas.fass.org/

The insulin-like growth factor 2 ( IGF2 ) gene intron3-g.3072G>A polymorphism is not the only Sus scrofa chromosome 2p mutation affecting meat production and carcass traits in pigs: Evidence from the effects of a cathepsin D ( CTSD ) gene polymorphism

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The objective of this study was to evaluate the effects of mutations in 2 genes [IGF2 and cathepsin D (CTSD)] that map on the telomeric end of the p arm of SSC2. In this region, an imprinted QTL affecting muscle mass and fat deposition was reported, and the IGF2 intron3-g.3072G>. A substitution was identified as the causative mutation. In the same chromosome region, we assigned, by linkage mapping, the CTSD gene, a lysosomal proteinase, for which we previously identified an SNP in the 3′-untranslated region (AM933484, g.70G>A). We have already shown strong effects of this CTSD mutation on several production traits in Italian Large White pigs, suggesting a possible independent role of this marker in fatness and meat deposition in pigs. To evaluate this hypothesis, after having refined the map position of the CTSD gene by radiation hybrid mapping, we analyzed the IGF2 and the CTSD polymorphisms in 270 Italian Large White and 311 Italian Duroc pigs, for which EBV and random residuals from fixed models were calculated for several traits. Different association analyses were carried out to distinguish the effects of the 2 close markers. In the Italian Large White pigs, the results for IGF2 were highly significant for all traits when using either EBV or random residuals (e.g., using EBV: lean cuts, P = 2.2 × 10−18; ADG, P = 2.6 × 10−16; backfat thickness, P = 2.2 × 10−9; feed:gain ratio, P = 2.3 × 10−9; ham weight, P = 1.5 × 10−6). No effect was observed for meat quality traits. The IGF2 intron3-g.3072G>A mutation did not show any association in the Italian Duroc pigs, probably because of the small variability at this polymorphic site for this breed. However, a significant association was evident for the CTSD marker with EBV of all carcass and production traits in Italian Duroc pigs (lean content, ADG, backfat thickness, feed:gain ratio) after excluding possible confounding effects of the IGF2 mutation. The effects of the CTSD g.70G>A mutation were also confirmed in a subset of Italian Large White animals carrying the homozygous genotype IGF2 intron3-g.3072GG, and by haplotype analysis between the markers of the 2 considered genes in the complete data set. Overall, these results indicate that the IGF2 intron3-g.3072G>A mutation is not the only polymorphism affecting fatness and muscle deposition on SSC2p. Therefore, the CTSD g.70G>A polymorphism could be used to increase selection efficiency in marker-assisted selection programs that already use the IGF2 mutation. However, for practical applications, because the CTSD gene should not be imprinted (we obtained this information from expression analysis in adult skeletal muscle), the different modes of inheritance of the 2 genes have to be considered.

For more information the full article can be found at http://jas.fass.org/

Relationships between colostrum production by primiparous sows and sow physiology around parturition

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Relationships between hormonal and metabolic changes around parturition and colostrum yield and composition were investigated in 16 Landrace × Large White primiparous sows. Blood samples were taken daily from d 105 of pregnancy to d 2 postpartum (with d 0 being the day of parturition). Colostrum samples were taken at the onset of parturition (T0), and then 3, 6, and 24 h later (T3, T6, and T24, respectively). Colostrum yield was calculated from the beginning of parturition until 24 h later by adding colostrum intake of individual piglets, which was estimated from their BW gain. Colostrum yield averaged 3.22kg. Four sows had very low colostrum production (1.10kg; n = 4), whereas the others produced between 2.83 and 4.64 kg of colostrum (3.93kg; n = 12). Compared with the high-colostrum-producing sows, the low-colostrum-producing sows tended to have greater plasma concentrations of progesterone during the 20-h prepartum and tended to have smaller plasma concentrations of prolactin 40 and 30 h before parturition. Sows with a low colostrum yield had greater plasma concentrations of glucose than sows with a high colostrum yield from d −9 to −2. At the onset of parturition, colostrum from lowproducing sows had greater percentages of DM, lipids, and GE, but less lactose, than that from high-producing sows. The Na:K ratio in colostrum during the 6 h postpartum was greater in low-producing sows than in high-producing sows, indicating that cellular junctions between epithelial mammary cells were less tightly closed. Concentrations of IgG in colostrum varied greatly between sows and decreased by approximately 80% between T0 and T24. Within high-producing sows, concentrations of IgG in colostrum at T0, T3, and T6 were negatively correlated with lactose concentrations in colostrum at the same times and were positively correlated with plasma concentrations of IGF-I measured from d −9 to 0. In contrast, no correlation was found between IgG concentrations in colostrum at any time and prolactin, estradiol-17β, progesterone, or cortisol. In conclusion, sows that produced a low yield of colostrum were characterized by a leaky mammary epithelium and reduced synthesis of lactose, related to delayed hormonal changes before parturition.

For more information the full article can be found at http://jas.fass.org/

Altrenogest treatment during late pregnancy did not reduce colostrum yield in primiparous sows

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The decrease in circulating concentrations of progesterone is the lactogenic trigger in many species. The aim of the present study was to determine the effect of an orally active progestogen, altrenogest, administered in late gestation, on lactogenesis in sows. Gilts were treated with altrenogest (20 mg/d) from d 109 to 112 of gestation (ALT112, n = 6) or d 113 (ALT113, n = 8) or were not treated (control, n = 9). Colostrum production, estimated from the BW gains of the piglets, was measured during 24 h starting at the onset of parturition. Colostrum samples were collected at the onset of parturition until 48 h later. Jugular blood samples were taken from d −8 prepartum until d 3 postpartum. Altrenogest treatment extended the gestation length of ALT113 sows in comparison with control sows (116.3 vs. 114.7d). Litter size and litter weight at birth did not differ between groups. Estimated colostrum yield was not reduced in altrenogest-treated sows compared with control sows (4.20 kg) and tended to be greater in ALT112 (4.73 kg) than in ALT113 sows (3.74 kg). Altrenogest reduced endogenous progesterone concentrations during the 2 d prepartum in ALT113 relative to control sows, likely because luteolysis occurred earlier in relation to parturition in ALT113 sows. Altrenogest reduced estradiol-17β concentrations during the 2 d prepartum in ALT113 and ALT112 sows. Altrenogest treatment did not influence the timing of the prepartum peak of prolactin in relation to parturition. The ALT113 sows had lesser concentrations of lactose in plasma and a lesser Na:K ratio in colostrum after parturition than Control and ALT112 sows, indicating that the junctions between their mammary epithelial cells were tighter. Concentrations of colostral IgG in sows that received altrenogest tended to be less than in control sows. In conclusion, altrenogest administered from d 109 to 112 or 113 of pregnancy did not affect lactogenesis in sows, possibly because the treatment delayed farrowing and main hormonal changes without affecting the relative chronology of these changes.

For more information the full article can be found at http://jas.fass.org/