Abstract The objective was to determine phosphorus (P) requirement of lactating sows using 24-hour urinary P excretion as the response criteria. The underlying assumption was that urinary P remains low and constant until the requirements are met then increases as P consumption increases. Thirty-six crossbred PIC Camborough sows (parity 3 to 7) were randomly assigned to 1 of 6 corn-soybean-meal diets with increasing dietary total P (tP) levels (0.40, 0.48, 0.56, 0.64, 0.72, and 0.80%) and a constant calcium (Ca) to tP ratio (1.25:1). Diets were fed from breeding until the end of lactation. Urine and blood samples were collected on days 4 and 18 of lactation and analyzed for P and Ca concentrations. Data were analyzed using MIXED and NLIN procedures of SAS. Phosphorus requirements were estimated using a broken-line regression model. Plasma Ca (ranging from 12.1 to 10.3 mg/dL) was not affected by dietary treatments, and was maintained within the normal physiological range on day 4 and 18 of lactation. Plasma P (ranging from 2.9 to 6.4 mg/dL) linearly increased (P < 0.05) with increasing dietary tP levels on day 4 and 18 of lactation. Only sows fed the 0.40% tP diet failed to maintain plasma P concentrations within the normal physiological range. Clinical signs of P and Ca deficiencies were not observed. Differences in sow and litter performance among treatments were not detected. A nonlinear response of urinary P excretion to dietary P intake was observed. Based on a broken-line linear model fit to 24-hour urinary P excretion, minimum tP requirements of sows at day 4 and 18 of lactation were 0.47 and 0.54%, respectively. In conclusion, 24-hour urine P excretion provided sensitive criteria for estimates of tP requirements in lactating sows. Efforts to adjust heteroscedasticity for animals fed dietary P above the estimated requirement need further evaluation.
Abstract The objective was to determine the effects of metabolizable energy (ME) and standardized ileal digestible (SID) lysine (Lys) levels on lactating sows and litter performance. A total of 600 sows (Camborough; PIC, Hendersonville, TN) were blocked by parity (P1, P2, P3+) on d 112 of gestation and allotted to 1 of 6 treatments arranged in a 2 x 3 factorial with the main effect of ME (3.2 and 3.4 Mcal/kg) and SID Lys (0.70, 0.85, and 1.00 %). Corn-soybean meal-based diets were fed from farrowing until weaning (d 21±2.3). Litters were cross-fostered until 48-h after farrowing to equalize litter size. Sows were weighed at d 112 of gestation and at weaning. Litter size and weight were collected at 24-h post-farrow and weaning. Daily feed intake was recorded from 48-h post-farrow until weaning. Data were analyzed using the GLIMMIX procedure of SAS with sow as the experimental unit. There was no evidence of interaction between ME and SID Lys for any response criteria. There was no evidence for an ME effect on sow performance. There was a quadratic effect (P< 0.05) of SID Lys on sow average daily feed intake, with the greatest intake at 0.85% SID Lys. Increasing SID Lys levels increased sow BW change (linear, P< 0.05). Litters from sows fed 3.4 Mcal of ME/kg had greater (P< 0.05) daily gain compared to those from sows fed 3.2 Mcal of ME/kg. Increasing SID Lys levels increased (linear, P< 0.05) litter weight at weaning and piglet daily gain. Wean-to-estrus interval, percentage of sows bred after weaning, total born on the subsequent parity, litter size at weaning, and percent of piglet removals were not influenced by dietary treatments. In summary, increasing ME levels did not affect sow performance, but improved litter and piglet daily gain. Increasing SID Lys levels improved both litter and sow performance.
Abstract A total of 386 mixed parity sows were used to evaluate the effects of different feeding regimes during the wean-to-estrus interval (WEI) on reproductive performance. At weaning, sows were blocked by genetic line (PIC Yorkshire and Camborough, Hendersonville, TN), parity category (Parity 1 and 4+), weaning visual body condition scores (BCS), and allotted to one of two treatments in a randomized complete block design. The number of weaned piglets of the previous lactation was balanced across treatments. Sows with BCS of 1 at weaning (based on a 3-point scale BCS system) were excluded from the study. A corn-soybean meal-soy hull-wheat bran-based gestation diet with 2.97 Mcal of ME/kg and 0.70% SID lysine was fed in the study. Treatments included two feeding regimes during WEI: T1) feed allowance of 4.5 kg/d with 200 g/day of top-dressed glucose; T2) feed allowance of 3 kg/day. Sows from T1 received two 2.25-kg meals at 0800 and 1630 with 200 g of glucose top-dressed in the morning meal. Sows from T2 received one 3-kg meal at 0800. Experimental data were analyzed using generalized linear mixed models with the GLIMMIX procedure of SAS and sow as the experimental unit. There was no evidence for differences between treatments on WEI (T1: 4.48 days; T2: 4.53 days; P = 0.60); percentage of sows that returned to estrus within 7 days post-weaning (T1: 86.01%; T2: 89.64%; P = 0.47); or conception rate at day 35 of the subsequent gestation (T1: 95.87%; T2: 98.50%; P = 0.44). In conclusion, feeding 4.5 kg of gestation diet and 200 g of glucose per day during WEI did not improve return to estrus or conception rate compared to feeding 3 kg of gestation diet per day for weaned sows with BCS greater than 1 on a 3-point scale.
Abstract Our objective was to determine the effects of immunocastration on growth performance, carcass characteristics and reproductive tract traits of gilts and boars. A total of 1,584 gilts and boars (PIC 337 x Camborough®, 6.11±0.29 kg, 20.64±0.81 days of age) were blocked by weaning group, and the gilt pens were randomly allotted to 1 of 2 treatments, which consisted of: T1) non-immunocastrated gilts, T2) immunocastrated gilts; whereas the boar pens were alloted to: T3) immunocastrated barrows. There were a total of 12 pens per treatment for T1 and T2, and 24 pens per treatment for T3, with 33 pigs per pen. The immunization against gonadotropin-releasing hormone (administrated with Vivax®, Zoetis, São Paulo, SP, Brazil) was given at 108±1.16 and 143±1.16 days of age (21 days before harvest). Growth performance was assessed from day 143 of age until harvest. Performance data were analyzed using the GLIMMIX procedure of SAS with pen as the experimental unit, and carcass and reproductive tract data were analyzed with pig as the experimental unit. Initial (day 143) and final (day 164) body weights were greater (P < 0.05) for T3 than T1 or T2, with no evidence for differences between T1 and T2 (P > 0.05). There were no evidence for treatment differences (P > 0.05) for average daily gain and feed efficiency. Average daily feed intake was reduced (P < 0.05) for T1 compared to T2 or T3. Hot carcass weight and lean content were greater (P < 0.05) and backfat thickness was thinner (P < 0.05) for T3 compared to T1 or T2, but no evidence for treatment differences (P > 0.05) were observed for loin depth. The ovary weights and the percentage of ovulatory follicles were greater (P < 0.05) for T1 compared to T2. Results of this study show no evidence for differences for immunocastration on growth performance of gilts or barrows. However, immunocastration influenced gilts’ reproductive tract traits.
Abstract A total of 1,900 pigs (PIC337×Camborough, initially 32.0 ± 0.52kg) were used to determine the effects of different nutrition plans on growth performance and behaviors of 32- to 128-kg grow-finish pigs. Pens of pigs were weighed, blocked by body weight, and randomly allotted to 1 of 5 treatments that consisted: TRT1) Single-phase program (30-135kg), standardized ileal digestible (SID) lysine:NE ratio at 107% of PIC recommendation at the mid-point of the weight range (referred as “PIC mid-point recommendation”); TRT2) Single-phase program (30-135kg), SID lysine:NE ratio at 125% of PIC mid-point recommendation; TRT3) Two-phase program (30-75 and 75-135kg), SID lysine:NE ratio at 96% and 106% of PIC mid-point recommendation, respectively; TRT4) Two-phase program (30-75 and 75-135kg), SID lysine:NE ratios at 101% of PIC mid-point recommendation in both phases; TRT5) Four-phase program (30-50, 50-75, 75-100, and 100-135kg), SID lysine:NE ratios at 100% of PIC mid-point recommendation in each phase. Dietary amino acids to lysine ratios were below PIC recommendations in TRT1 and TRT3, and met or were above PIC recommendations in TRT2, TRT4, and TRT5. Pigs and feeders were weighed, and ear and tail lesion were scored and recorded every 2 to 3 weeks. From 32- to 81-kg, pigs fed TRT1 diet had reduced average daily gain (ADG, P < 0.05) and gain to feed ratio (G:F, P < 0.05) compared with all other groups (Table 1). Overall, pigs fed TRT2 diet had the greatest ADG, G:F, and lean percentage (P < 0.05). Pig fed TRT1 diet had a greater overall incidence rate of ear and flank lesions compared with the ones in other treatments (P < 0.05). In the current experiment, grow-finish pigs fed with a single-phase nutrition plan containing lower SID Lys levels and amino acid ratios compared with PIC recommendations had reduced performance during the grower phase and greater overall incidence rate of vices.
Two experiments were conducted to determine the effects of calcium to phosphorus (Ca:P) ratio in diets adequate in standardized total tract digestible (STTD) P on performance of 26- to 127-kg pigs fed diets with or without phytase. Pens of pigs (n = 1,134 in Exp. 1 and n = 1,215 in Exp. 2, initially 26.3 and 25.3 kg) were blocked by body weight (BW) and allotted to treatments in a randomized complete block design. There were 27 pigs per pen with 7 and 9 replicates per treatment in Exp. 1 and Exp. 2, respectively. Treatments were formulated to contain 0.75:1, 1.00:1, 1.25:1, 1.50:1, 1.75:1, and 2.00:1 analyzed Ca:P ratios in Exp. 1, and 0.75:1, 1.00:1, 1.25:1, 1.50:1, and 2.00:1 analyzed Ca:P ratios in Exp. 2. These correspond to a range of 0.96:1 to 2.67:1 and 0.95:1 to 2.07:1 STTD Ca:STTD P ratios in Exp. 1 and Exp. 2, respectively. Experiment 2 diets contained 1,000 phytase units of Ronozyme HiPhos 2500 (DSM Nutritional Products, Inc., Parsippany, NJ) with release values of 0.132% STTD P, 0.144% total Ca, and 0.096% STTD Ca. Diets contained 122% of NRC (2012) STTD P estimates for the weight range across 4 phases. In Exp. 1, increasing Ca:P ratio increased (quadratic, P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI). Feed efficiency (G:F) worsened (quadratic, P < 0.05) at the highest ratio. Hot carcass weight (HCW) and bone ash increased (quadratic, P < 0.05) while carcass yield decreased (linear, P < 0.10) with increasing Ca:P ratio. The maximum responses in ADG, HCW, and bone ash were estimated at 1.38:1, 1.25:1, and 1.93:1 analyzed Ca:P and at 1.82:1, 1.64:1, and 2.57:1 STTD Ca:STTD P, respectively. In Exp. 2, increasing Ca:P ratio increased (quadratic, P < 0.05) ADG and bone ash, and improved G:F (linear, P < 0.05). There was a quadratic increase (P < 0.05) in HCW and decrease in carcass yield (P < 0.10). The maximum responses in ADG, HCW, and bone ash were estimated at 1.63:1, 1.11:1 to 1.60:1, and 1.25:1 analyzed Ca:P and at 1.75:1, 1.28:1 to 1.71:1, and 1.40:1 STTD Ca:STTD P, respectively. Expressing ADG on a STTD Ca:STTD P basis provided a more consistent estimate of the ideal Ca:P ratio among the 2 studies than analyzed Ca to analyzed P ratio. A STTD Ca:STTD P ratio between 1.75:1 to 1.82:1 can be used for 26- to 127-kg pigs that are fed diets adequate in STTD P with or without added phytase to maximize growth rate without reducing bone ash.
Knowledge of energy use by the pig is essential to predict, optimize, and formulate diets to achieve expected performance. Taking into consideration the productive and financial implications of the energy density of the diet, the objective of this project was to develop a tool to estimate the dietary NE concentration that yields maximum profitability for growing-finishing pigs. A Microsoft Excel®-based model was developed to contrast dietary NE currently utilized by the user with recommended concentrations intended to maximize profitability in user-defined production and economic scenarios. The model is divided into 3 sections: 1) model inputs (including economics, production, and dietary criteria), 2) model calculations and optimization (including growth performance and carcass yield predictions, and profitability indicators), and 3) model outputs (including recommended dietary NE concentrations and profitability indicators). To calculate pig performance, the model uses prediction equations for ADG. Where ADG, g = 0.1135 × NE, kcal/kg + 8.8142 × Avg BW, kg - 0.05068 × (Avg BW, kg)2 + 275.99, when Lys or other amino acids are not limiting. To calculate G:F, the assumption is that G:F has a linear relationship with NE in the diet. Therefore, a 1% change in NE will result in a 1% change in G:F. The model also uses the NDF content of the diet to estimate the effect of the diet on dressing percentage, where carcass yield, % = 0.03492 × WP, d – 0.05092 × NDF1, % – 0.06897 × NDF2, % – 0.00289 × (NDF2, % × WP, d) + 76.0769, where WP is the withdrawal period and NDF1 and NDF2 are the NDF levels in the dietary phase prior to the final phase and in the final phase before marketing, respectively. The model predicts responses for an average pig without population variance included. For profitability calculations, a non-linear mathematical programming model was designed to select the optimum values of dietary NE that yield the maximum profitability. In this model, the objective function of income over total cost on a live- or carcass-basis is maximized by selecting the optimal value of NE in each dietary phase. In conclusion, the model herein can be used to predict the value of dietary NE that yields maximum profitability for growing-finishing pigs.
Foi conduzido um experimento para se avaliarem níveis de proteína bruta (PB) com suplementação de aminoácidos sintéticos em rações para leitoas mantidas em ambiente termoneutro. Trinta e cinco leitoas mestiças (Landrace x Large White) com peso médio inicial de 60,5 kg foram distribuídas em delineamento experimental inteiramente ao acaso, com cinco tratamentos (17,3; 16,0; 14,7; 13,4 e 12,1% PB, com suplementação de lisina, metionina, triptofano, treonina e valina, para se manter a qualidade protéica entre os tratamentos), sete repetições e um animal por unidade experimental. As rações experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram o peso médio de 100,6 kg. Não se observou efeito da redução do nível de proteína bruta da ração sobre o desempenho (consumo de ração, ganho de peso e conversão alimentar) dos animais. As variáveis avaliadas na carcaça (comprimento da carcaça, área-de-olho de lombo, espessura de toucinho, rendimentos de carcaça, de carne magra, de gordura e de pernil) também não foram influenciadas pela redução do nível de PB das rações. Os tratamentos influenciaram os pesos absoluto e relativo do fígado, observando-se os maiores valores nos animais que receberam a ração com 16,0% de PB. A redução do nível de PB de 17,3 para 12,1% em rações para leitoas mantidas em ambiente termoneutro dos 60 aos 100 kg não prejudica o desempenho, desde que as rações sejam devidamente suplementadas com os aminoácidos essenciais limitantes.
Feed accounts for a significant portion of swine production cost, with dietary energy alone representing more than half of the total cost. Considering the financial implications of determining the energy content of the diet, the objective of this research project was to develop a tool to accurately estimate the dietary NE content that yields maximum profitability for growing-finishing pigs. A Microsoft Excel®-based model was developed to contrast dietary NE defined by the user with recommended concentrations that are intended to maximize profitability in user defined production and economic scenarios. To calculate pig performance, the model uses prediction equations for ADG and feed efficiency. In addition, the model also uses the NDF content of the diet because of its effect on dressing percentage. For profitability calculations, a non-linear mathematical programming model was designed to select the optimum dietary NE content that yields the greatest income over total cost per pig on a live or carcass basis. The model can be used to predict dietary NE content that yields the highest economic benefit considering dynamic productive and economic scenarios. The model can be downloaded at www.ksuswine.org.