Effects of increasing standardized ileal digestible lysine during gestation on reproductive performance of gilts and sows

Limited information is available on lysine requirement estimates of modern, high-producing gestating sows Therefore, the objective of this study was to evaluate the effects of increasing standardized ileal digestible (SID) lysine during gestation on piglet birthweight and reproductive performance of gilts and sows. A total of 936 females (498 gilts, 438 sows; Camborough®, PIC, Hendersonville, TN) were group-housed (approximately 275 females per pen) and individually fed with electronic sow feeders. Females were moved from the breeding stall to pens on d 4 of gestation and allotted to one of four dietary treatments on d 5. Dietary treatments included increasing SID lysine intake (11.0, 13.5, 16.0, and 18.5 g/d). Gilts (parity 1) and sows (parity 2+) received 2.1 and 2.3 kg (22.2 and 24.3 MJ net energy per day) of feed throughout the entire gestation period, respectively. Dietary treatments were achieved by different blends of low (0.48% SID lysine) and high (0.88% SID lysine) lysine diets, prepared by changing the amount of corn and soybean meal in these two diets. Female weight and backfat were recorded on d 4 and 111 of gestation. Individual piglet weight was obtained within 12 h of birth on litters from 895 females. Final weight, and calculated maternal BW, body lipid, and body lean at d 111 of gestation increased (linear, P < 0.01) for gilts and sows as SID lysine increased. There was no evidence for differences in final backfat depth. Average total born for gilts and sows was 15.3 and 16.0 pigs with no evidence for differences among treatments. The percentage of pigs born alive increased (P = 0.01) with increasing SID lysine intake for sows, but not in gilts as a result of a treatment by parity group interaction (P = 0.04) for percentage of stillborn pigs. Increasing SID lysine intake during gestation did not affect the percentage of mummified fetuses, total born, or birthweight of piglets born alive in this study. In addition, increasing SID lysine intake during gestation did not affect subsequent reproductive performance. In conclusion, increasing dietary SID lysine intake in gestation increased female BW, without changing backfat depth. The minimal effects on female reproductive performance and piglet birthweight suggest that 11 g/day of SID lysine intake appears to be adequate for gestating gilts and sows; however, providing sows with 18.5 g/d SID lysine reduced (P = 0.01) stillbirth rate by 2.3 percentage points.     

Effects of sex and dietary lysine on performances and serum and meat traits in finisher pigs

A total of 160 Duroc×(Landrace×Large White) pigs, 50% barrows and 50% gilts, of 28.3±4.52 kg of BW were used to study the effect of lysine (Lys) restriction in the finisher period, on growth performances and serum and carcass and meat quality traits. The grower diet (from 30 to 90 kg BW) was slightly Lys-restricted (7.8 g standardised ileal digestible (SID) Lys/kg) in accordance with results from a previous trial. During the finisher period (90 to 130 kg BW), four experimental diets with decreasing SID Lys contents (6.3, 5.6, 4.2 and 3.2 g/kg) were tested. Each of the eight treatments (two sexes×four levels of Lys) was replicated five times. Each replicate was a pen with four pigs allocated together. When animals achieved 129±2.59 kg were slaughtered and carcass and meat characteristics were evaluated. No significant interaction sex×diet was found. During the finisher period, barrows grew faster (P<0.001) and ate more feed (P<0.001) but tended to be less efficient (P=0.055) than gilts. The Lys restriction affected linearly (P<0.001) all productive performance traits; daily BW gain and feed intake decreased and feed conversion ratio increased. Also, the concentration of serum urea at slaughter tended to be higher in barrows than in gilts (P=0.065) and was reduced quadratically by the restriction of Lys in feed (P<0.001). Carcasses from barrows had higher backfat thickness (P<0.01) and lower weight of main trimmed lean cuts (ham+shoulder+loin; P<0.05) than those from gilts. The Lys restriction during the finisher period decreased carcass yield (quadratic; P<0.001) and the weight of major cuts (linear; P<0.001). Sex and diet had limited effect on meat characteristics; the Lys restriction decreased quadratically the proportion of protein (P<0.01) and increased linearly the intramuscular fat (IMF) content (P<0.001). We can conclude that dietary Lys restriction during finisher period in pigs impaired growth performances and was not successful to increase the carcass fat deposition, although it could have positive effects on IMF proportion of pork.     

Effects of konjac flour inclusion in gestation diets on the nutrient digestibility,lactation feed intake and reproductive performance of sows

This study was conducted to investigate the effects of konjac flour (KF) inclusion in gestation diets of sows on nutrients digestibility, lactation feed intake, reproductive performance of sows and preweaning performance of piglets. Two isoenergetic and isonitrogenous gestation diets were formulated: a control diet and a 2.1% KF-supplemented diet (KF diet). Both diets had the same NDF and insoluble fiber (ISF) levels, but the KF diet had higher soluble fiber (SF) level. The day after breeding, 96 multiparous sows were assigned to the two dietary treatments. Restrict-fed during gestation, in contrast, all sows were offered the same lactation diet ad libitum. Response criteria included sow BW, backfat depth, lactation feed intake, weaning-to-estrus interval, litter size and piglet’s weight at parturition and day 21 of lactation. On day 60 of gestation, 20 sows were used to measure nutrient digestibility. Results showed that the digestibility of dry matter, gross energy, crude fiber and ADF were not affected by the dietary treatments. The inclusion of KF in gestation diets increased NDF digestibility (P<0.05) and tended to increase the digestibility of CP (P=0.05) compared with the control diet group. In addition, dietary treatment during gestation did not affect litter size, BW and backfat gain during gestation, lactation weight, backfat loss or weaning-to-estrus interval of sows. However, sows fed the KF diet consumed more (P<0.05) lactation diet per day than sows in the control group. Accordingly, sows fed the KF diet showed greater average piglet weights on day 21 of lactation (P=0.09), and the litter weight of sows fed the KF diet on day 21 of lactation increased by 3.95 kg compared with sows fed the control diet (not significant). In conclusion, the inclusion of KF in gestation diets increased lactation feed intake of sows and tended to improve litter performance.     

An association analysis of sow parity,live-weight and back-fat depth as indicators of sow productivity

Understanding how critical sow live-weight and back-fat depth during gestation are in ensuring optimum sow productivity is important. The objective of this study was to quantify the association between sow parity, live-weight and back-fat depth during gestation with subsequent sow reproductive performance. Records of 1058 sows and 13 827 piglets from 10 trials on two research farms between the years 2005 and 2015 were analysed. Sows ranged from parity 1 to 6 with the number of sows per parity distributed as follows: 232, 277, 180, 131, 132 and 106, respectively. Variables that were analysed included total born (TB), born alive (BA), piglet birth weight (BtWT), pre-weaning mortality (PWM), piglet wean weight (WnWT), number of piglets weaned (Wn), wean to service interval (WSI), piglets born alive in subsequent farrowing and sow lactation feed intake. Calculated variables included the within-litter CV in birth weight (LtV), pre-weaning growth rate per litter (PWG), total litter gain (TLG), lactation efficiency and litter size reared after cross-fostering. Data were analysed using linear mixed models accounting for covariance among records. Third and fourth parity sows had more (P<0.05) TB, BA and heavier BtWT compared with gilts and parity 6 sow contemporaries. Parities 2 and 3 sows weaned more (P<0.05) piglets than older sows. These piglets had heavier (P<0.05) birth weights than those from gilt litters. LtV and PWM were greater (P<0.01) in litters born to parity 5 sows than those born to younger sows. Sow live-weight and back-fat depth at service, days 25 and 50 of gestation were not associated with TB, BA, BtWT, LtV, PWG, WnWT or lactation efficiency (P>0.05). Heavier sow live-weight throughout gestation was associated with an increase in PWM (P<0.01) and reduced Wn and lactation feed intake (P<0.05). Deeper back-fat in late gestation was associated with fewer (P<0.05) BA but heavier (P<0.05) BtWT, whereas deeper back-fat depth throughout gestation was associated with reduced (P<0.01) lactation feed intake. Sow back-fat depth was not associated with LtV, PWG, TLG, WSI or piglets born alive in subsequent farrowing (P>0.05). In conclusion, this study showed that sow parity, live-weight and back-fat depth can be used as indicators of reproductive performance. In addition, this study also provides validation for future development of a benchmarking tool to monitor and improve the productivity of modern sow herd.     

The effect of immunocastration and a diet based on granulated barley on growth performance and carcass,meat and fat quality in heavy gilts

A total of 48 Duroc×(Landrace×Large White) gilts of 33.2 kg BW were used to investigate the influence of immunocastration and diet on growth performance and carcass, meat and fat quality. Four treatments were arranged factorially (2×2) with two sexes (immunocastrated gilts: IG v. entire gilts: EG) and two dietary treatments (a commercial feedstuff as control v. granulated barley as a single major ingredient) provided during the finishing period (from 103 to 126 kg BW). There were four replicates of three pigs per treatment. At the end of the trial, the IGs grew faster (P<0.05) and ate more feed (P<0.05) than the EGs. Carcasses from the IGs had thicker backfat depth than those from the EGs (P<0.01) and carried out a lower percentage of rejected carcasses (P<0.05) at slaughterhouse owing to lack of fat. Meat from the IGs tended to have higher intramuscular fat (IMF) content in the Longissimus thoracis (LT) muscle than that from the EGs (P=0.09). In addition, immunocastration increased the total saturated fatty-acid proportion in subcutaneous fat and IMF (P<0.001) and decreased the total monounsaturated fatty acid (MUFA) and total polyunsaturated fatty acid (PUFA) percentages in subcutaneous backfat (P<0.05 and P<0.001, respectively) and in IMF (P<0.01 and P=0.06, respectively). The use of a diet based on granulated barley during the finishing period had no effect on growth performance but tended to increase IMF content in the LT muscle (P<0.06), and increased MUFA (P<0.05) and decreased PUFA (P<0.01) proportions in omental fat. It is concluded that immunocastration of gilts intended for dry-cured ham industry improved some aspects of growth performance and carcass and meat quality, whereas granulated barley had scarce effect on productive traits and fatty-acid profile but tended to improve IMF content.     

The effect of granulated barley as single major ingredient in the growing or finishing diet on productive performance,carcass, meat and fat quality of heavy pigs

A total of 48 Duroc × (Large White × Landrace) gilts of 46.8 kg BW (86 ± 3 days of age) were used to investigate the effect of diet during the growing and finishing periods on growth performance and carcass, meat and fat quality. The control diet consisted of a commercial feedstuff and the granulated barley diet had that cereal as the single major ingredient. There were three treatments: (i) control diet provided from 45.6 to 127.8 kg BW (C group), (ii) control diet from 47.0 to 91.8 kg BW and granulated barley from 91.8 to 129.7 kg BW (C + GB group) and (iii) granulated barley from 47.9 to 93.1 kg BW and control diet from 93.1 to 135.1 kg BW (GB + C group). Each treatment was replicated eight times, with two pigs per replicate. The C group grew faster (P < 0.001) and had a better feed conversion ratio (P < 0.001) than the GB + C group, with C + GB being intermediate. Carcasses from C + GB gilts had higher backfat depth than those from C gilts, with GB + C being intermediate (P < 0.05). Also, the main joints (ham + shoulder + loin) had a higher (P < 0.01) yield in carcass in the GB + C group than in the C group, with C + GB being intermediate. The intramuscular fat (IMF) content was higher (P < 0.001) in loin from C + GB and GB + C gilts than in C gilts. The IMF of loin from C + GB gilts had higher (P < 0.05) C18:1n-9 and total monounsaturated fatty acid (FA) proportions than that from C gilts, whereas the C18:2n-6 and total polyunsaturated FA percentages were lower (P < 0.05) in C + GB gilts than in the remaining gilts. The total saturated FA percentage was lower (P < 0.05) in loin from GB + C than in that from C gilts. Hams from C + GB and GB + C gilts had higher (P < 0.05) C18:1n-9 and total monounsaturated FA proportions and lower C18:2n-6 and total polyunsaturated FA contents than those from C gilts. We can conclude that granulated barley provided during the growing or the finishing period improved some carcass and meat characteristics of heavy gilts desirable for dry-cured ham production.     

Effect of advancing the supply of finisher diet on growth performances and carcass and pork quality of heavy barrows and gilts

A total of 120 Duroc×(Large White×Landrace) pigs, 50% barrows and 50% gilts, with 54.1±0.14 kg BW and 103±3 days of age, were used to study the effect of advancing the shift to a standard finisher feed from 100 to 90 and 80 kg BW on production performances and carcass and pork quality. Each of the six treatments (two sexes×three BWs at time of feeding shift) was replicated four times and the experimental unit was the pen (with five pigs for growth performance and carcass variables and three pigs for pork and fat traits). The grower (163 g CP and 9.5 g total Lys/kg) and the finisher diets (152 g CP and 7.9 g total Lys/kg) were based on maize, barley and vegetal protein concentrates, contained 13.39 MJ metabolizable energy/kg and were offered ad libitum through the trial. Pigs intended for dry-cured product elaboration were slaughtered at 170±3 days of age as average (124 and 115 kg BW for barrows and gilts, respectively). For the overall period, barrows ate more feed (P<0.001) and grew faster (P=0.03) than gilts. No effect of feed shift was observed on growth performances, although the average daily CP intake (P=0.01) and feeding costs (P=0.04) were reduced by advancing the transition to the finisher feed. Carcasses from barrows were heavier (P<0.001) and had wider backfat depth (P<0.001) than those from gilts but no significant differences were observed in the meat chemical composition. The feed change schedule did not modify carcass or meat traits. It is concluded that an early shift to the finisher feed (at 80 kg BW instead of 100 kg BW) might be an interesting strategy in pigs intended for dry-cured products because, although it neither increased body fatness nor improved pork quality, CP intake and feeding costs were reduced without impairment of growth performances. Results were similar for barrows and gilts.     

The effects of immunization against gonadotropin-releasing hormone on growth performance,reproductive activity and carcass traits of heavy weight gilts

Heavy weight gilts commonly show signs of oestrus during the late finishing phase, which results in a period of reduced feed intake and growth rate. Immunization against gonadotropin-releasing hormone (GnRH) (IM, immunocastration) was developed for finishing boars and recently extrapolated to females. Immunocastration acts by suppressing reproductive activity and improving the growth potential. The objective of this study was to evaluate the effects of IM on growth performance, reproductive activity and carcass characteristics of late finishing gilts. Seventy-two gilts (63.49 ± 0.39 kg) were either injected with saline (Intact) or immunized against GnRH (Immunized). The study consisted of three experimental periods: between the first to second immunization (V1 to V2, 15 to 19 weeks of age), from the second immunization to the beginning of daily boar exposure (DBE) (V2 to DBE, 19 to 21 weeks of age) and from the beginning of DBE to slaughter (S) (DBE to S, 21 to 25 weeks of age). Immunized gilts showed an overall increase (from 15 to 25 weeks) of 3.90 kg (P < 0.05) of live weight, 56 g (P < 0.05) of average daily gain (ADG) and 250 g (P < 0.001) of average daily feed intake (ADFI). Immunized gilts had a greater ADFI (+240 g, P < 0.05) and worse feed conversion ratio (+0.26, P < 0.05) from 19 (V2) to 21 weeks of age (before DBE). Furthermore, those females had higher feed intake (+410 g; P < 0.001) plus greater daily weight gain (+92 g; P < 0.05) from V2 to S, and from DBE to S (+470 g of ADFI, P < 0.001; +129 g of ADG, P < 0.01, respectively). Immunocastration had no effect on backfat thickness, lean meat percentage and weight, cold carcass yield or loin depth (P > 0.05). Immunized gilts showed 4.4% increased cold carcass weight (P < 0.01) and 10.6% greater gross flank weight (P < 0.001). Immunization against GnRH did not influence shoulder, collar, loin, belly or ham weights. Nor did it influence belly fat thickness, or meat, skin plus fat and bones yields of cold ham (P > 0.05). Immunocastration reduced ovarian and uterine weights by 82% (P < 0.001) and 93% (P < 0.001), respectively, and suppressed oestrus manifestation in all gilts in the immunized group (P < 0.001). These results indicate that immunization against GnRH is a promising tool for stimulating growth performance with no detrimental effects on carcass quality of heavy weight finishing gilts, by means of oestrus suppression.     

Effect of level of feed restriction during growth and/or fattening on fatty acid composition and lipogenic enzyme activity in heavy pigs

The influence of feeding system on growth performance, carcass characteristics, and fatty acids profile of subcutaneous backfat and lipogenic enzymes activity was studied. The following feeding systems were applied: HH: group of 12 pigs fed with a high feeding level during growth and fattening periods; HL: group of 12 pigs fed with a high feeding level during growth period and a low feeding level during fattening period; LH: group of 12 pigs fed with a low feeding level during growth period and a high feeding level during fattening period; LL: group of 12 pigs fed with a low feeding system during growth and fattening periods. The high and low feeding levels applied during growth and fattening periods were 70 and 35 g feed/kg live weight^0.75 (LW^0.75) day and 121 and 87 g feed/kg LW^0.75 day, respectively. The duration of the growth period was 163 days in all groups. The ages at slaughter of HH, HL, LH and LL pigs were approximately 383, 406, 439 and 503 days, respectively. The HH and LL pigs had the higher and lower average daily gain respectively, while the LH pigs presented the best feed conversion ratio during fattening period. At slaughter, the LL pigs had the higher value of loin width and the lower values of backfat thicknesses and Longissimus dorsi muscle intramuscular fat percentage (P<0.05). The subcutaneous backfat outer and inner layers from LH and LL pigs had a significantly (P<0.05) higher proportion of C18:1 n-9 and ΣMUFA (monounsaturated) acids than those from HH and HL pigs. The subcutaneous backfat inner layer from LL pigs had a lower C16:0 and ΣSFA (saturated) acids proportions than those from remaining groups of pigs. The activity of the fatty acid synthase (FAS) and glucose-6-phosphate dehydrogenase (G6PD) enzymes, measured in subcutaneous backfat, at the end of growing period was significantly (P<0.05) higher in pigs fed high feeding level during growing phase. An increase of feeding level during the fattening phase led to an increase in the activity of G6PD enzyme. In conclusion, a marked effect of feeding system was observed on pig productivity and fatty acid composition.     

Effects of dietary menhaden oil on growth and reproduction in gilts farrowed by sows that consumed diets containing menhaden oil during gestation and lactation

In sows, n-3 fatty acids increase litter sizes, however, effects on gilt reproductive development have not been adequately studied. Moreover, not determined are effects of feeding n-3 fatty acids to sows on reproduction in offspring. The objective here was to determine effects of 4% dietary menhaden oil on growth and puberty in gilts farrowed by sows fed menhaden oil. Sows (n = 44) were assigned to: (1) control gestation and lactation diets, or (2) diets including menhaden oil. For primiparous sows only, total litter size and born alive were greater (P < 0.05) in females fed menhaden oil. Conversely, pigs from primiparous controls were heavier (P < 0.05) than pigs from primiparous sows fed menhaden oil (parity by diet interactions, P < 0.01). Diet did not affect (P > 0.20) other sow and litter characteristics. At weaning, 84 gilts from control- or menhaden oil sows were placed three gilts per pen and provided control diets or diets containing menhaden oil. Nursery and grow-finish feed intake and feed efficiency were similar (P > 0.21) for gilts from the different sows and weight gain was similar (P > 0.24) for gilts fed control or menhaden diets. Gilts fed menhaden oil tended to eat less in the nursery (1.18±0.08 kg v. 0.98±0.08 kg; P = 0.09) and overall (1.83±0.04 kg v. 1.72±0.04 kg; P = 0.06). Thus, overall feed to gain was greater (2.52±0.03 v. 2.33±0.03; P < 0.01) and nursery (2.12±0.04 v. 1.80±0.04; P = 0.10) and grow-finish (3.07±0.19 v. 2.58±0.19; P = 0.08) feed to gain tended to be greater, for control gilts. Age at puberty was greater (P = 0.02) for gilts from menhaden oil-fed sows (205.1±3.2 days) compared to gilts from controls (193.9±3.2 days) and tended to be greater (P = 0.09), for controls (203.5±3.2 days) compared to gilts fed menhaden oil (195.5±3.2 days). A tendency existed (P = 0.09) for greater follicular fluid in gilts fed menhaden oil, however, ovulation rate and ovarian, luteal and uterine weights were not affected by sow diet, gilt diet or the interaction (P > 0.23). Feeding gilts menhaden oil enhanced feed efficiency and hastened puberty onset. Gilts from sows consuming menhaden oil exhibited delayed puberty and retaining females from sows fed this feedstuff may be ill advised.     

Growth,meat and feed efficiency traits of lambs born to ewes submitted to energy restriction during mid-gestation

The objective of this study was to evaluate the effects of the energy restriction of gestation of adult ewes from day 45 to day 115 on lamb live performance parameters, carcass and meat traits. In experiment I, dietary energy was restricted at 70% of the metabolizable energy (ME) requirements, after which ewes were re-fed ad libitum until lambing. In experiment II, dietary energy was restricted at 60% of the ME requirements, and ewes were re-fed to ME requirements until lambing. All ewes grazed together from the end of the restriction periods to weaning. Lambs were weaned and lot fed until slaughter. Feed intake, weight gain and feed efficiency were recorded, and body fat thickness and ribeye area (REA) were measured in the longissimus thoracis muscle. After slaughter, carcass weight and yield, fat depth, carcass and leg length, and frenched rack and leg weights and yields were determined. Muscle fiber type composition, Warner-Bratzler shear force, pH and color were determined in the longissimus lumborum muscle. In experiment I, energy restriction followed by ad libitum feeding affected lamb birth weight (P<0.05); however, no effects (P>0.05) were observed on later BW, REA, BF or carcass traits. Lambs born to non-restricted-fed ewes had higher (P<0.05) weight and yield of the frenched rack cut and their meat tended (P=0.11) to be tender compared with that of lambs from restricted ewes. The percentage of oxidative muscle fibers was lower for lambs born to non-restricted ewes (P<0.05); however, no effects of ewe treatment were observed on other muscle fiber types. For experiment II, energy restriction followed by ME requirements feeding, affected (P<0.01) pre-weaning live weight gain, weaning and final weights. Lambs from restricted ewes had higher (P<0.05) feed intake as % of leg weight and a trend to be less efficient (P=0.16) than lambs from unrestricted dams. Ribeye area and BF were not influenced by treatment. Treatment significantly affected slaughter weight, but had no effects on carcass yield and traits or on meat traits. The results obtained in both experiments indicate submitting ewes to energy restriction during gestation affects the performance of their progeny but the final outcome would depend on the ewe’s re-feeding level during late gestation and the capacity of the offspring to compensate the in utero restriction after birth.     

Effect of feed restriction on the performance and behaviour of pigs immunologically castrated with Improvac®

For centuries, entire male pigs have been castrated to reduce the risk of boar taint. However, physical castration of pig is increasingly being questioned with regard to animal welfare considerations. Immunization against gonadotrophin releasing hormone (GnRH) provides an alternative to physical castration. Using the currently available commercial product (Improvac®; Pfizer Animal Health), a two-dose regimen of a GnRH vaccine is administered. After the second vaccination, a substantial increase in feed consumption has been reported, which may be associated with increased body fatness and decreased feed efficiency when compared with unvaccinated entire male pigs. The aim of the present study was to investigate the effect of a feed restriction on these traits and on the behaviour of 120 group-housed entire males (five pigs/pen) vaccinated against GnRH. The first vaccination was performed at 62 days of age and the second (V2) at 130 days of age. Pigs were slaughtered in two batches 4 to 5 weeks after V2. They were either offered feed ad libitum over the 22 to 114 kg BW range (AL treatment) or ad libitum up to a maximum of 2.50 (R2.50 treatment) or 2.75 kg/day per pig (R2.75 treatment). Behavioural observations and skin lesion scoring were conducted 1 week before V2, and 1 and 3 weeks after V2. At slaughter, the volumetric lean meat content was measured using an X-ray computed tomography scanner. Between V2 and slaughter, the average feed intakes for the R2.75 and R2.50 treatments were 15% and 22% lower than the average AL feed intake (3.20 kg/day), respectively. Feed restriction was associated with a reduced average daily gain after V2 (846, 932 and 1061 g/day in the R2.50, R2.75 and AL groups, P < 0.01) but had no effect on the feed conversion ratio (3.00 kg feed/kg BW gain on average, P = 0.62). No difference was observed in the lean meat content (71.8%, 70.7% and 70.4% in the R2.50, R2.75 and AL groups, P = 0.14), despite a reduced backfat thickness measured in restrictively fed pigs (12.0, 13.0 and 13.6 mm in the R2.50, R2.75 and AL groups, P < 0.01). Higher skin lesion scores were observed 3 weeks after V2 in R2.50 and R2.75 pigs than in the AL ones (scores 33.4, 27.7 and 25.5, respectively, P = 0.04). These results, combined with an unimproved feed efficiency and no marked change in carcass characteristics, suggest that immunologically castrated pigs should not be restrictively fed during the late finishing period.     

Impact of feed restriction on the performance of highly prolific lactating sows and its effect on the subsequent lactation

A total of 50 mixed parity sows of a high-prolificacy genetic line were used to evaluate the impact of feed restriction during lactation on their production and reproductive performance and their performance in the subsequent lactation. From day 7 of lactation, sows were distributed according to a completely randomized experimental design into two treatments. In treatment 1, sows were fed 8.0 kg feed/day (control) and in treatment 2, sows were fed 4.0 kg/day. The same suckling pressure was maintained until weaning on day 28 of lactation. Average minimum and maximum temperatures measured during the experimental period were 32.1°C and 16.5°C, respectively. Control sows presented significantly higher feed intake (P<0.001) compared with the restricted sows (6.43 v. 4.14 kg/day, respectively). Treatments influenced BW and backfat thickness losses (P<0.001). Control sows lost less BW than the restricted-fed sows (7.8 v. 28.2 kg). Restricted-fed sows lost more backfat thickness than those in the control group (3.97 v. 2.07 mm; P<0.01). Restricted-fed sows tended (P<0.10) to be lighter at weaning compared with the control sows (211 v. 227 kg). The composition of BW loss was influenced by the treatments (P<0.001), as the restricted-fed sows lost more body protein, lipids and energy compared with the control sows (3.90 v. 0.98 kg, 11.78 v. 4.83 kg and 584 v. 224 MJ, respectively). Litter weight gain was greater (P<0.05) in control sows than in restricted-fed sows (2.70 v. 2.43 kg/day). Daily milk production was 19% higher (P<0.01) in the control sows compared with the restricted-fed sows (8.33 v. 6.99 kg/day). However, restricted-fed sows presented a higher (P<0.05) lactation efficiency than the sows of the control group (82.30% v. 72.93%). No differences were detected (P>0.10) in weaning-to-estrus interval and averaged 4.3 days. No effect of the treatment (P>0.10) was observed on any of the studied performance traits in the subsequent lactation, except for litter size at birth that tended (15.2 v. 14.1; P<0.10) to be lower for the restricted sows. In conclusion, the present study demonstrated that feed restriction during lactation leads to intense catabolism of the body tissues of sows, negatively affecting their milk production, and the litter weight gain and possibly number of piglets born in the next litter. On the other hand, restricted-fed sows are more efficient, producing more milk per amount of feed intake.     

Effect of sex,dietary glycerol or dietary fat during late fattening,on fatty acid composition and positional distribution of fatty acids within the triglyceride in pigs

The effect of sex, source of saturated fat (lard v. palm oil) and glycerol inclusion in the fattening diet on composition and fatty acid positional distribution in the triglyceride molecule was studied in pigs from 78 to 110 kg BW. Average daily gain and carcass characteristics, including ham and loin weight, were not affected by dietary treatment but sex affected backfat depth (P<0.01). A significant interaction between sex and glycerol inclusion was observed; dietary glycerol increased lean content in gilts but not in barrows (P<0.05 for the interaction). Individual and total saturated fatty acid (SFA) concentrations were greater in barrows than in gilts. In contrast, the concentration of total polyunsaturated fatty acids (PUFA) and of C18:2n-6, C18:3n-3, C20:3n-9 and C20:4n-6 in the intramuscular fat (IMF) was higher (P<0.05) in gilts than in barrows. Sex did not affect total monounsaturated fatty acids (MUFA) concentration in the IMF. The proportion of SFA in the subcutaneous fat (SF) was higher in barrows than in gilts (P<0.001). Within the individual SFA, sex affected only the concentrations of C14:0 and C16:0 (P<0.001). Dietary fat did not affect total SFA or PUFA concentrations of the IMF but the subcutaneous total MUFA concentration tended to be higher (P=0.079) in pigs fed lard than in pigs fed palm oil. Dietary glycerol increased total MUFA and C18:1n-9 concentration in the IMF and increased total MUFA and decreased C18:2n-6, C18:3n-3 and total PUFA concentrations in the SF. The data indicate that altering the fatty acid composition of the triglyceride molecule at the 2-position, by dietary intervention during the fattening phase, is very limited.     

Effect of ractopamine and conjugated linoleic acid on performance of late finishing pigs

The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.     

Plane of nutrition during gestation affects reproductive performance and retention rate of hyperprolific sows under commercial conditions

Defining a maternal plane of nutrition during gestation is pivotal for improving sow productivity and the cost-effectiveness of feeding. The benefits of increasing the amount of feed during late gestation have been controversial. The objective of this study was to investigate the effects of different planes of nutrition during gestation on reproductive performance of hyperprolific sows and pre-weaning litter performance. One hundred and thirty-five gestating sows were randomly assigned to one of three planes of nutrition throughout parities three and four (P4), as follows: Req – plane designed to meet requirements of prolific sows (2.3 kg per day from day 1 to 21; 1.8 kg per day from day 22 to 75; 2.3 kg per day from day 76 to farrowing); Bump – plane designed as the Req, with increased feed intake during late gestation (3.0 kg per day from day 91 to farrowing); and Maintenance – plane designed to closely meet maintenance requirements of sows (1.8 kg per day from day 1 to farrowing). All treatments were fed the same gestation diet (2.50 MCal NE/kg; 0.67% SID Lysine; 15.17% CP). Sow biometrical parameters at farrowing and at weaning, and litter characteristics were recorded. Also, blood samples were collected for pre- and post-prandial serum glucose and plasma insulin, as well as triglycerides, calcium, and phosphorus analyses. Culling, stratified by cause, and retention rates were recorded in all treatments for each parity. Over two parities, Bump sows had higher weight gain and, at P4, had a higher number of piglets born alive (P < 0.05). Bump sows lost more weight between the end of gestation and weaning over two parities (P < 0.05). Maintenance sows showed reduced body condition score with a higher percentage of piglets removed throughout lactation (due to inappetence and inability to reach the udder) at P4 (P = 0.03). Pre- and post-prandial glucose levels were higher in Bump sows, as well as post-prandial insulin and phosphorus levels at P4 (P < 0.05). Bump sows also showed increased plasma triglycerides compared to the other treatments (P = 0.03). Retention rate was reduced in Maintenance compared to Bump and Req sows at parity 5 (P = 0.02). Taken together, our results indicate that higher feed intake allowance during late gestation may improve the sow’s nutritional status triggering positive results on litter size of hyperprolific sows (e.g., more than 17 total born). However, body condition score must be carefully evaluated to prevent excessive weight gain during successive parities.     

Pigs that are divergent in feed efficiency,differ in intestinal enzyme and nutrient transporter gene expression,nutrient digestibility and microbial activity

Feed efficiency is an important trait in the future sustainability of pig production, however, the mechanisms involved are not fully elucidated. The objective of this study was to examine nutrient digestibility, organ weights, select bacterial populations, volatile fatty acids (VFA’s), enzyme and intestinal nutrient transporter gene expression in a pig population divergent in feed efficiency. Male pigs (n=75; initial BW 22.4 kg SEM 2.03 kg) were fed a standard finishing diet for 43 days before slaughter to evaluate feed intake and growth for the purpose of calculating residual feed intake (RFI). Phenotypic RFI was calculated as the residuals from a regression model regressing average daily feed intake (ADFI) on average daily gain (ADG) and midtest BW^0.60 (MBW). On day 115, 16 pigs (85 kg SEM 2.8 kg), designated as high RFI (HRFI) and low RFI (LRFI) were slaughtered and digesta was collected to calculate the coefficient of apparent ileal digestibility (CAID), total tract nutrient digestibility (CATTD), microbial populations and VFA’s. Intestinal tissue was collected to examine intestinal nutrient transporter and enzyme gene expression. The LRFI pigs had lower ADFI (P<0.001), improved feed conversion ratio (P<0.001) and an improved RFI value relative to HRFI pigs (0.19 v. −0.14 SEM 0.08; P<0.001). The LRFI pigs had an increased CAID of gross energy (GE), and an improved CATTD of GE, nitrogen and dry matter compared to HRFI pigs (P<0.05). The LRFI pigs had higher relative gene expression levels of fatty acid binding transporter 2 (FABP2) (P<0.01), the sodium/glucose co-transporter 1 (SGLT1) (P<0.05), the glucose transporter GLUT2 (P<0.10), and the enzyme sucrase–isomaltase (SI) (P<0.05) in the jejunum. The LRFI pigs had increased populations of lactobacillus spp. in the caecum compared with HRFI pigs. In colonic digesta HRFI pigs had increased acetic acid concentrations (P<0.05). Differences in nutrient digestibility, intestinal microbial populations and gene expression levels of intestinal nutrient transporters could contribute to the biological processes responsible for feed efficiency in pigs.     

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on growth performance and carcass quality of offspring

Effects of a marine oil-based n-3 LCPUFA supplement (mLCPUFA) fed from weaning until the end of the next lactation to sows with a predicted low litter birth weight (LBW) phenotype on growth performance and carcass quality of litters born to these sows were studied, based on the hypothesis that LBW litters would benefit most from mLCPUFA supplementation. Sows were allocated to be fed either standard corn/soybean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. The growth performance from birth until slaughter of the litters with the lowest average birth weight in each treatment (n=24 per treatment) is reported in this paper. At weaning, each litter was split between two nursery pens with three to six pigs per pen. At the end of the 5-week nursery period, two barrows and two gilts from each litter that had individual birth weights closest to their litter average birth weight, were moved to experimental grow–finish pens (barn A), where they were housed as two pigs per pen, sorted by sex within litter. Remaining pigs in each litter were moved to another grow–finish barn (barn B) and kept in mixed-sex pens of up to 10 littermates. After 8 weeks, one of the two pigs in each pen in barn A was relocated to the pens holding their respective littermates in barn B. The remaining barrows and gilts were individually housed in the pens in barn A until slaughter. Maternal mLCPUFA supplementation increased docosahexaenoic acid (DHA) concentration in the brain, liver and Semitendinosus muscle of stillborn pigs (P<0.01), did not affect eicosapentaenoic acid and DHA concentrations in sow serum at the end of lactation, and did not affect average daily gain, average daily feed intake or feed utilization efficiency of the offspring. BW was higher (P<0.01) in the second half of the grow–finish phase in pigs from mLCPUFA sows compared with controls in barn A, where space and competition for feed was minimal, but not barn B. Carcass quality was not affected by treatment for pigs from barn A, but maternal mLCPUFA supplementation negatively affected carcass quality in pigs from barn B. Collectively, these results suggest that nutritional supplementation of sows can have lasting effects on litter development, but that feeding mLCPUFA to sows during gestation and lactation was not effective in improving growth rates or carcass quality of LBW litters.     

Effect of age at the beginning of the free-range fattening period on growth and carcass and fat quality in Iberian pigs

Abstract

This experiment was carried out to study the influence of age at the beginning of the free-range fattening period (traditional pigs, TP, age 12 months vs. young pigs, YP, age 8 months) on the performance of Iberian pigs. During 152 days prior to the fattening period, TP and YP pigs received 1.7 and 2.6 kg feed per day, respectively. During fattening, TP pigs had a higher average daily gain (p < 0.05) than YP pigs. The proportions of PUFA and n-3 fatty acids of the outer and inner layers of subcutaneous backfat were higher in TP than in YP pigs (p < 0.05), while the proportions of C16:0 and SFA in the inner layer of subcutaneous backfat were greater in YP than in TP pigs (p < 0.05). The ratio of n-6/n-3 in subcutaneous backfat was lower in TP than in YP pigs (p < 0.05). The percentage of intramuscular fat in longissimus dorsi muscle was higher in TP than in YP pigs (p < 0.05). The relationship between the percentage of intramuscular fat in longissimus dorsi muscle and average daily gain during the free-range fattening period adjusted to a quadratic function (p < 0.05). The concentration of α- and γ-tocopherol in subcutaneous backfat at slaughter was significantly higher in TP than in YP pigs (p < 0.05). It is concluded that Iberian pigs that have 8 months of age at the beginning of free-range feeding have adequate commercial quality.     

Effect of average litter weight in pigs on growth performance,carcass characteristics and meat quality of the offspring as depending on birth weight

Offspring born from normal litter size (10 to 15 piglets) but classified as having lower than average birth weight (average of the sow herd used: 1.46 ± 0.2 kg; mean ± s.d.) carry at birth negative phenotypic traits normally associated with intrauterine growth restriction, such as brain-sparing and impaired myofiber hyperplasia. The objective of the study was to assess long-term effects of intrauterine crowding by comparing postnatal performance, carcass characteristics and pork quality of offspring born from litters with higher (>1.7 kg) or lower (<1.3 kg) than average litter birth weight. From a population of multiparous Swiss Large White sows (parity 2 to 6), 16 litters with high (H = 1.75 kg) or low (L = 1.26 kg) average litter birth weight were selected. At farrowing, two female pigs and two castrated pigs were chosen from each litter: from the H-litters those with the intermediate (H_I = 1.79 kg) and lowest (H_L = 1.40 kg) birth weight, and from L-litters those with the highest (L_H = 1.49 kg) and intermediate (L_I = 1.26 kg) birth weight. Average birth weight of the selected H_I and L_I piglets differed (P < 0.05), whereas birth weight of the H_L- and L_H-piglets were similar (P > 0.05). These pigs were fattened in group pen and slaughtered at 165 days of age. Pre-weaning performance of the litters and growth performance, carcass and meat quality traits of the selected pigs were assessed. Number of stillborn and pig mortality were greater (P < 0.05) in L- than in H-litters. Consequently, fewer (P < 0.05) piglets were weaned and average litter weaning weight decreased by 38% (P < 0.05). The selected pigs of the L-litters displayed catch-up growth during the starter and grower–finisher periods, leading to similar (P > 0.05) slaughter weight at 165 days of age. However, H_L-gilts were more feed efficient and had leaner carcasses than H_I-, L_H- and L_I-pigs (birth weight class × gender interaction P < 0.05). Meat quality traits were mostly similar between groups. The marked between-litter birth weight variation observed in normal size litters had therefore no evident negative impact on growth potential and quality of pigs from the lower birth weight group.