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Effects of restricting energy during the gilt developmental period on growth and reproduction of lines differing in lean growth rate: Responses in feed intake, growth, and age at puberty

Posted in: Energy, Production by admin on July 26, 2011 | No Comments

The overall objective was to compare reproductive performance through 4 parities of gilts developed with ad libitum access to feed or with restriction of energy to 75% of ad libitum intake. Effects on growth and pubertal development are reported. The experiment was a 2 × 2 factorial with 661 gilts. One-half of the gilts (n = 330) were allowed ad libitum access to feed from weaning to breeding at 235 d of age (AL), and 331 littermates were developed with ad libitum access to feed to 123 d of age and then restricted to 75% of ad libitum intake to 235 d of age (Res). Diets for gilts on regimen AL were formulated to meet requirements for growth. All nutrients except energy and selenium were increased in the diet fed to gilts on regimen Res so that nutrient intake per unit of BW was expected to be similar to that of gilts on regimen AL. Sires of all gilts were from an industry maternal line. Dams were either an industry Large White-Landrace cross, or Nebraska selection Line 45, producing gilts denoted as LW/LR and L45X, respectively. Traits were recorded every 2 wk. Recording of feed intake and BW began at 53 d of age, and recording of backfat (BF) and LM area (LMA) began at 123 d of age. Estrus detection began at 140 d of age to determine age at puberty (AP). The G:F ratio from 123 to 235 d of age for gilts on the AL regimen was greater (0.269 vs. 0.257) than for gilts on the Res regimen; the greatest difference occurred in the first 2-wk period following feed restriction. The LW/ LR gilts were heavier, had less BF, and had greater LMA than L45X gilts, but interactions with feeding regimen and period of development existed. Feed restriction reduced BW, BF, LMA, and ratio of BF to BW, but had little effect on ratio of LMA to BW. More L45X gilts than LW/LR gilts (98 vs. 93%) and more gilts developed on regimen AL than regimen Res (98 vs. 91%) expressed estrus. Mean age at puberty was 178.6 d for LW/LR and 173.0 d for L45X gilts and 174.1 d for regimen AL and 177.5 d for regimen Res. The Res regimen delayed pubertal development. Subsequently, it will be important to determine effects on reproduction through 4 parities.

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

Neonatal piglet traits of importance for survival in crates and indoor pens

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The primary aim of the present study was to investigate whether the same piglet traits contributed to the same causes of neonatal piglet mortality in crates (CT) and pens (PN). Gilts originating from 2 distinct genetic groups that differed in breeding value for piglet survival rate at d 5 (SR5) were used. These were distributed to farrow in either PN or CT as follows: high-SR5 and CT (n = 30); low-SR5 and CT (n = 27); high-SR5 and PN (n = 22); and low-SR5 and PN (n = 24). Data on individual piglets were collected at birth, including interbirth interval; birth order; birth weight; rectal temperature at birth, 2 h after birth, and 24 h after birth; cordal plasma lactate; and latency to first suckle. Based on autopsy, causes of mortality were divided into stillborn, bitten to death, starvation, crushed, disease, and other causes. Potential risk factors of dying were estimated using a GLM with a logit link function. No significant effect of housing was observed on the odds of a piglet being stillborn, being crushed, or dying of starvation. No significant differences were observed between the 2 genetic groups for any category of mortality. Piglet traits for pre- and postnatal survival were the same for CT and PN. The odds of being stillborn were increased in piglets born late in the birth order, after a long interbirth interval, and with a lighter birth weight. The lighter the birth weight of the piglets, the greater were the odds of being crushed and dying of starvation. The lower the rectal temperature 2 h after birth, the greater were the odds of being crushed, starving, or dying of diseases. Increased cordal plasma lactate increased the odds of dying from starvation. In both CT and PN, the birth weight, body temperature 2 h after birth, and birth process were important traits related to crushing, starvation, and disease. Neither housing nor breeding value influenced mortality or traits of importance for the inborn viability of piglets. The results emphasize that the microclimate in the PN for newborn piglets and its heat-preserving properties are more important for survival than whether the sow is crated or penned.

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

Survey among Belgian pig producers about the introduction of group housing systems for gestating sows

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There is a global move from individual to group housing of gestating sows. In the European Union, individual gestating stalls will be banned by 2013. Just like in other industrialized regions, these stalls have been the standard housing system for intensively kept sows from the 1960s onward in the Flemish region of Belgium. Because the socioeconomic consequences for the pig industry may be far-reaching and because farmer attitude may influence the realization of the hoped-for improvement in animal welfare in practice, we conducted a survey from 2003 until 2009 among representative samples of Flemish pig producers every 2 yr. The share of farms with group housing increased from 10.5% in 2003 to 29.8% in 2007, but then dropped to 24.6% in 2009. It appears that after 2005 users of old group housing systems in particular stopped farming. Because sow herd size increased more on farms with vs. without group housing and because the proportion of the herd that was group-housed also tended to increase between 2003 to 2009, the change to group housing took place faster when expressed at the level of the sow (from 9.1% in 2003 to 34.1% in 2009) instead of farm. The percentage of farmers planning to convert to group housing within 2 yr was 4.1% in 2003, and 6 to 7% thereafter. These were typically young farmers with a large sow herd and with a likely successor. Free access stalls were the most common group housing system (31% of farms, 37% of sows). Their popularity is expected to increase further at the expense of electronic feeding stations, ad libitum feeding, and stalls/troughs with manual feed delivery. User satisfaction was generally high but depended on whether or not all gestating sows were kept in group, the provisioning of environmental enrichment, the age, and type of system. The main criteria for choosing a certain group housing system were the investment costs and sow health and welfare. The importance of economic reasons and type of labor decreased with the age of the system. In 2003 and 2005 the main reason for not having converted to group housing was that farmers would stop keeping sows by 2013. In 2007 and 2009 the reasons mainly concerned uncertainty about the future and maximally delaying the conversion. Belgium is one of the European Union countries where the pig industry is expected to undergo drastic changes during the few years remaining before the ban on individual housing

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

Whole-genome association analyses for lifetime reproductive traits in the pig

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Profits for commercial pork producers vary in part because of sow productivity or sow productive life (SPL) and replacement costs. During the last decade, culling rates of sows have increased to more than 50% in the United States. Both SPL and culling rates are influenced by genetic and nongenetic factors. A whole-genome association study was conducted for pig lifetime reproductive traits, including lifetime total number born (LTNB), lifetime number born alive (LNBA), removal parity, and the ratio between lifetime nonproductive days and herd life. The proportion of phenotypic variance explained by markers was 0.15 for LTNB and LNBA, 0.12 for removal parity, and 0.06 for the ratio between lifetime nonproductive days and herd life. Several informative QTL regions (e.g., 14 QTL regions for LTNB) and genes within the regions (e.g., SLC22A18 on SSC2 for LTNB) were associated with lifetime reproductive traits in this study. Genes associated with LTNB and LNBA were similar, reflecting the high genetic correlation between these traits. Functional annotation revealed that many genes at the associated regions are expressed in reproductive tissues. For instance, the SLC22A18 gene on SSC2 associated with LTNB has been shown to be expressed in the placenta of mice. Many of the QTL regions showing associations coincided with previously identified QTL for fat deposition. This reinforces the role of fat regulation for lifetime reproductive traits. Overall, this whole-genome association study provides a list of genomic locations and markers associated with pig lifetime reproductive traits that could be considered for SPL in future studies.

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

Effect of incremental levels of red blood cells on growth performance and carcass traits of finishing pigs

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Three experiments were conducted to determine the effect of incremental levels of red blood cells (RBC; 0 to 4%, Exp. 1; 0 to 2%, Exp. 2 and 3) on growth performance and carcass traits of finishing pigs. Dietary treatments were formulated to meet or exceed the nutrient requirements of barrows and gilts gaining 350 g of lean BW gain per day and were formulated to contain 0.52% apparent ileal digestible (AID) Lys for barrows and 0.59% AID Lys for gilts. In Exp. 1, barrows and gilts (2 replicates of barrows and 2 of gilts; 4 pigs per pen) were fed 0, 1, 2, 3, or 4% RBC. Initial BW (mean was 84.6 and 82.42) and final BW was 118.7 and 120.0kg for barrows and gilts, respectively. Two barrows and 2 gilts per pen were randomly selected and slaughtered for collection of carcass measurements. Experiment 2 was similar to Exp. 1, except 0, 1, or 2% RBC were added. Initial BW was 82.5 and 79.2kg, and final BW was 125.5 and 119.8kg for barrows and gilts, respectively. Each dietary treatment had 4 replicates per sex with 4 pigs per pen. One barrow and 1 gilt per treatment replicate were randomly selected and slaughtered for collection of carcass traits and viscera weights. Experiment 3 was similar to Exp. 2 except only barrows were used, and the initial and final BW were 86.0 and 133.4 kg, respectively. Each dietary treatment had 4 replicates with 3 pigs per pen, and all pigs were slaughtered for collection of carcass traits and viscera weights. In Exp. 1, final BW, ADG, and G:F were decreased linearly as RBC addition increased, but ADFI was not affected. With increased RBC addition, average backfat increased and fat free lean decreased. There was a quadratic effect on dressing percentage (DP); the 2% RBC addition increased DP, but the 3 and 4% additions decreased DP. The RBC addition had no effect on any remaining carcass measurements. In Exp. 2, there was a quadratic effect of RBC addition on average backfat; the 1% RBC addition decreased backfat, but the 2% addition returned backfat to the level of the control pigs. There was no effect on any other response variable. In Exp. 3, with increased RBC addition, average backfat linearly decreased and large intestine percentage increased. There was no effect of RBC addition on any other response variable. Our data indicate that feeding 3 or 4% RBC decreases growth performance of finishing pigs. However, feeding 1 or 2% RBC to finishing pigs had no detrimental effects on growth performance and increased DP in one experiment.

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

Performance and phosphorus balance of pigs fed diets formulated on the basis of values for standardized total tract digestibility of phosphorus

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Three experiments were conducted to test the hypotheses that pigs fed diets that are equal in digestible phosphorus (P) will perform equally regardless of the concentration of total P in the diets, and that the addition of microbial phytase, distillers dried grains with solubles (DDGS), or a combination of phytase and DDGS will result in a reduction in P excretion. In Exp. 1, a P-free diet and 6 diets containing corn, soybean meal (SBM), or DDGS without or with microbial phytase (500 phytase units per kg) were formulated. Diets were fed for 12 d to 42 pigs (initial BW = 13.5kg) housed in metabolism cages that allowed for total collections of feces. Basal endogenous P losses were determined to be 199 mg/kg of DMI for pigs fed the P-free diet. Addition of phytase increased the standardized total tract digestibility (STTD) of P in corn (64.4 vs. 26.4%) and SBM (74.9 vs. 48.3%), but there was no effect of the addition of phytase on the STTD of P in DDGS (75.5 vs. 72.9%). In Exp. 2, a total of 160 pigs (initial BW = 11.25kg; 4 pigs/pen) were allotted to 4 corn- and SBM-based diets with 2 amounts of phytase (0 or 500 phytase units per kg) and 2 amounts of DDGS (0 or 20%) in a 2 × 2 factorial arrangement of treatments. All diets were formulated to contain 0.32% STTD of P according to the STTD values determined in Exp. 1. Diets were fed for 21 d and results indicated that inclusion of phytase in the diet containing no DDGS tended to decrease G:F, but inclusion of 20% DDGS in the diets tended to increase ADG, ADFI, and final BW. In Exp. 3, the diets used in Exp. 2 were fed to 24 pigs (initial BW = 14.6kg) that were placed in metabolism cages individually. Feces and urine were collected for 5 d. Phytase and DDGS increased the apparent total tract digestibility of P in the diets. Absorption of P was greater in pigs fed corn-SBM-DDGS diets than pigs fed corn-SBM diets, and phytase, DDGS, or the combination of phytase and DDGS reduced P excretion. In conclusion, the addition of phytase increased the STTD of P in corn and SBM, but had no effect on the STTD of P in DDGS. Diets may be formulated based on STTD values without compromising pig performance, and dietary phytase, DDGS, or the combination of phytase and DDGS will reduce P excretion by growing pigs.

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

Ileal digestibility of amino acids in conventional, fermented, and enzyme-treated soybean meal and in soy protein isolate, fish meal, and casein fed to weanling pigs

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An experiment was conducted to determine the apparent (AID) and standardized (SID) ileal digestibility of CP and AA in weanling pigs of 4 soybean products, fish meal, and casein. The 4 soybean products were conventional dehulled soybean meal (SBM), soy protein isolate (SPI), fermented soybean meal (FSBM), and enzyme-treated soybean meal (ESBM). Seven weanling barrows (initial BW: 10.9kg) were individually fitted with a T-cannula in the distal ileum. The barrows were allotted to a 7 × 7 Latin square design with 7 diets and seven 7-d periods. Six cornstarch-based diets were prepared using each of the protein sources as the sole source of CP and AA. An Nfree diet was used to measure basal endogenous losses of CP and AA. Results showed that except for Lys, the AID and SID of AA in FSBM was not different from SBM, and with a few exceptions, the AID and SID of most AA in SBM, FSBM, and ESBM were not different from each other and from the AID and SID of AA in fish meal. Likewise, the AID and SID of AA in ESBM and SPI were not different, but the AID and SID of most AA in SPI were greater than in SBM and FSBM. The AID and SID of most AA in SPI were not different from the AID and SID of AA in casein. In conclusion, FSBM and ESBM had similar SID of most AA as SBM, but SPI has the greatest SID of AA among the 4 soybean products. Casein had the greatest SID of AA among the protein sources studied.

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

Energy value of wheat distillers grains with solubles for growing pigs and adult sows

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Two experiments were conducted to determine the total tract digestibility of energy and the DE and ME values of 10 European wheat dried distillers grains with solubles (DDGS) fed to growing pigs and adult sows. The wheat DDGS were obtained from European ethanol plants and selected to get a large variability. One control diet, based on wheat (87.2%), soybean meal (10.0%), and minerals and vitamins, and 10 experimental diets prepared from the control diet and 25% each of the 10 sources of DDGS, were fed to 66 crossbred barrows (6 per diet) according to a factorial arrangement or 6 adult sows according to a pseudo Latin square design. Animals were placed in metabolism cages that allowed for the total, but separate, collection of feces and urine for 8 to 10 d after a 7- to 11-d adaptation period. By subtracting the contribution from the control diet in the DDGS-containing diets (i.e., difference method), N and GE digestibilities and DE and ME values for each source of DDGS were calculated. The energy digestibility in wheat DDGS averaged 66.5% (56.3 to 76.0%) and 71.2% (59.7 to 78.2%) in growing pigs and adult sows, respectively. Consequently, average (range) DE values of DDGS were 14.0 (11.8 to 16.2) and 14.9 (12.5 to 16.4) MJ/kg of DM for growing pigs and adult sows, respectively. Our data show that DE content of wheat DDGS can be predicted from their ADF content or from the lightness score (L). By excluding the dark and overheated samples (L <50) with the least energy digestibility and DE values, the average energy digestibility values were 69.5 and 74.4% in growing pigs and adult sows, respectively, with corresponding DE values of 14.6 and 15.6 MJ/kg DM, which are more representative of a well-controlled process for DDGS preparation. The negative effect of L on energy value and energy digestibility indicates that the occurrence of Maillard reactions should be reduced to maximize the energy value of wheat DDGS for pigs.

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

Effects of feeding diets naturally contaminated with Fusarium mycotoxins on protein metabolism in late gestation and lactation of first-parity sows

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A study was conducted to assess the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins to sows on the capacity for protein synthesis in skeletal muscle, the protein content per cellular unit, and the efficacy of a polymeric glucomannan adsorbent (GMA) to prevent these effects in late gestation and in lactation. Thirty-two Yorkshire sows were assigned to 4 treatment groups (8 per treatment) from 91d of gestation up to weaning on d 21 after farrowing. Diets included control, contaminated grains, and contaminated grains + 0.2% GMA. A fourth treatment of feeding sows the control diet at a restricted feed allowance was also included. The variables measured include ADFI, average daily BW change, serum total protein, urea, and ammonia, and skeletal muscle DNA, RNA, and protein. To assess the capacity for protein synthesis, ratios of RNA:DNA, and RNA:protein were compared among dietary treatments. To assess the degree of muscle protein mobilization in gestation and lactation, ratios of protein:DNA were compared among dietary treatments. Muscle samples were obtained from the triceps brachii. Blood and muscle samples were obtained 3 times: the first was obtained 1 d before the sows began to receive the experimental diets (90d of gestation), a second sample was obtained 14 d later (104d of gestation), and the third sample was obtained 10 d after farrowing. Serum ammonia concentrations were similar in sows fed the contaminated feed and sows fed the restricted feed compared with controls, but serum ammonia concentrations were greater in sows fed contaminated feed and restricted-fed sows compared with sows fed the contaminated grains plus GMA on 104d of gestation. There were no reductions in the capacity for protein synthesis caused by mycotoxins or restricted feeding compared with controls. A reduction in ADFI was observed in sows fed the 2 contaminated diets in lactation. Muscle protein mobilization was not affected by diet, but a reduction in the content of protein per cellular unit was observed in lactation compared with gestation. Reduction in protein:DNA could be caused by the catabolic state in lactation, which was augmented by a low ADFI. The rate of muscle mobilization could be the result of the indirect effect of the reduction in ADFI in lactation rather than a direct effect of Fusarium mycotoxins in the capacity for protein synthesis.

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

Epistatic analysis of carcass characteristics in pigs reveals genomic interactions between quantitative trait loci attributable to additive and dominance genetic effects

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The present study focused on the identification of epistatic QTL pairs for body composition traits (carcass cut, lean tissue, and fat tissue weights) measured at slaughter weight (140 kg of BW) in a 3-generation full-sib population developed by crossing Pietrain sires with a crossbred dam line. Depending on the trait, phenotypic observations were available for 306 to 315 F2 animals. For the QTL analysis, 386 animals were genotyped for 88 molecular markers covering chromosomes SSC1, SSC2, SSC4, SSC6, SSC7, SSC8, SSC9, SSC10, SSC13, and SSC14. In total, 23 significant epistatic QTL pairs were identified, with the additive × additive genetic interaction being the most prevalent. Epistatic QTL were identified across all chromosomes except for SSC13, and epistatic QTL pairs accounted for between 5.8 and 10.2% of the phenotypic variance. Seven epistatic QTL pairs were between QTL that resided on the same chromosome, and 16 were between QTL that resided on different chromosomes. Sus scrofa chromosome 1, SSC2, SSC4, SSC6, SSC8, and SSC9 harbored the greatest number of epistatic QTL. The epistatic QTL pair with the greatest effect was for the entire loin weight between 2 locations on SSC7, explaining 10.2% of the phenotypic variance. Epistatic associations were identified between regions of the genome that contain the IGF-2 or melanocortin-4 receptor genes, with QTL residing in other genomic locations. Quantitative trait loci in the region of the melanocortin-4 receptor gene and on SSC7 showed significant positive dominance effects for entire belly weight, which were offset by negative dominance × dominance interactions between these QTL. In contrast, the QTL in the region of the IGF-2 gene showed significant negative dominance effects for entire ham weight, which were largely overcompensated for by positive additive × dominance genetic effects with a QTL on SSC9. The study shows that epistasis is of great importance for the genomic regulation of body composition in pigs and contributes substantially to the variation in complex traits.

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

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