Validation of flank-to-flank allometric equations in predicting weight of lactating sows and lactation weight change

The objectives of this study were to validate the use of flank-to-flank measurement in predicting weight of lactating sows and to determine the accuracy of the developed models in estimating lactation weight change. A total of 70 lactating sows (PIC Line 1050) were used in this study. Flank-to-flank measurement and body weight were measured on each individual sow after farrowing and at weaning. Flank-to-flank measurement and weight of lactating sows was positively correlated (R2 = 0.61; P<.0001) with the following equation: BW0.33, kg = 0.0371 x Flank-to-flank (cm) + 2.161. Weights of sows post-farrowing and at weaning were lower (P<0.03) when predicted with the previous allometric model developed from growing pigs and sows than their actual weights or weights predicted using the lactating sow model. Likewise, absolute residuals for post-farrowing and weaning weights using a previous allometric model developed from growing pigs and gestating sows were greater (P<0.02) than those of the lactating sow model. There were no differences (P<0.89) between the predicted weights using the lactating sow model and their actual weights. There also were no differences between the actual average weight loss (P<0.14) and the predicted loss using the lactating sow model. Using the model previously developed with growing pigs and gestating sows resulted in 15.5 lb (P<0.007) greater than the actual average weight loss. In conclusion, flank-to-flank measurement can be used as a predictor of weight of lactating sows, with the relationship having less accuracy than those used for growing-finishing pigs, gestating sows, and boars. The pig allometric equation cannot be used to estimate weights of lactating sows and lactation weight change. The developed lactating sow model was more appropriate in estimating weights and weight loss at the herd level, but needs to be validated on other sows before use can be recommended

Amino acid digestibility and energy content of corn distillers meal for swine

An experiment was conducted to determine the apparent ileal digestibility and standardized ileal digestibility of amino acids and energy of corn distillers meal in pigs. Five growing barrows (initially 150 lb) were allotted to one of two diets in a crossover design. One diet contained corn distillers meal (66.7%) as the sole protein source. The second diet was nitrogen-free to determine basal endogenous AA losses. Ileal digesta and fecal samples were collected during each period and analyzed for amino acid and energy contents. Based on these analyses, apparent ileal digestibility (AID), standardized ileal digestibility (SID), gross energy (GE), digestible energy (DE), metabolizable energy (ME), and net energy (NE) were calculated. Apparent ileal digestibility values of lysine, methionine, and threonine in corn distillers meal were 47.2, 79.4, and 64.1%, respectively while SID values of the same amino acids were 50.4, 80.4, and 66.3%, respectively. The ME, DE, and estimated NE values of the corn distillers meal were 1,137; 1,233; and 813 kcal/lb, respectively

Validation of control diets for lactose and fish meal replacement studies in nursery pigs

The objective of this study was to develop and validate control test diets to be used for lactose and fish meal replacement studies in nursery pigs. A total of 180 nursery pigs (PIC, initially 16.6 lb and 28 ± 2 d of age) were blocked by initial weight and randomly allotted to 1 of the following 6 dietary treatments: (1) negative control (NC) diet based on corn-soybean meal, (2) NC + 10% food-grade whey, (3) NC + 10% feed-grade whey, (4) Diet 2 + 4.5% select menhaden fish meal, (5) Diet 2 + 2.25% select menhaden fish meal and 1.25% spray-dried blood cells, and (6) Diet 2 + synthetic amino acids. Diets 4 to 6 also contained 10% food-grade whey. Each treatment had 5 pigs per pen and 6 replications (pens). Diets were formulated to contain 1.37% standardized ileal digestible lysine and 1,495 kcal ME/lb and were fed in meal form. Newly-weaned pigs (21 ± 2 d of age) were fed a common segregated early weaning and transition diet for 7 days then fed the experimental phase 2 diets for 21 d. From d 0 to 7 and 0 to 14, pigs fed the diet containing 10% feed-grade whey tended to have greater ADG (P 0.36) ADG and BW compared with pigs fed the diet containing the same food-grade whey without specialty proteins but tended to have poorer (P 0.15) were observed in ADG, ADFI, F/G, and pig BW among the dietary treatments. More research is needed to evaluate the use of synthetic amino acids as a replacement for high quality protein ingredients in nursery diets. When reviewing data from previous studies, it is apparent that further development of the control diets for testing lactose and fish meal sources is needed so that the predicted response is consistent

Predicting growth rates of adult working boars in a commercial boar stud

There is almost no information on ideal growth rates for adult boars, but estimates can be made if the relationship between boar weight and age is known. Therefore, this study was aimed to predict growth rates in adult working boars in a commercial boar stud. A total of 214 adult working boars from two genetic lines in a commercial boar stud were individually weighed on a platform scale. Age of the boar was recorded at the time of weighing. A regression equation to predict boar weight as a function of age was developed by using PROC REG of SAS. The model was used to predict BW on a daily basis, and ADG was derived as the difference between two predicted BW values. Factorial estimates of daily ME requirement and feeding rates were determined. The energy requirement for weight gain was computed by using the predicted ADG as a guide in setting target weight gains. Results showed a positive curvilinear response (P<0.01) to describe the relationship between boar weight and age. Predicted ADG decreased in a curvilinear manner as the boars aged. In conclusion, on-farm growth rates can be predicted effectively by relating weight with age, taken from a representative number of boars in a given farm population. These data can then be used to develop farm specific feeding programs or to set different growth curves for experimental purposes

Influence of organoleptic properties of the feed and nursery diet complexity on preweaning and nursery performance

Two experiments were performed to determine the effects of adding an enhanced feed flavor to the creep feed on the proportion of piglets consuming creep feed within litters and preweaning performance (Exp. 1) and the interactive effects of preweaning exposure to the flavor, nursery diet complexity, and flavor addition to nursery diets on postweaning performance (Exp. 2). In Exp. 1, 50 sows (PIC 1050) were blocked according to parity and date of farrowing and allotted to 2 experimental treatments in a randomized complete block design. Treatment 1 was a creep diet with no flavor (negative control), and treatment 2 was the negative control diet with the enhanced milky flavor (Luctarom) included at 1,500 ppm (3 lb/ton). Both creep diets contained 1.0% chromic oxide and were offered ad libitum from d 18 until weaning on d 21. In Exp. 2, 480 weanling pigs (PIC, 14.5 lb and 20 ± 2 d) from Exp. 1 were blocked by initial weight and allotted to 1 of 8 treatments in a randomized complete block design with preweaning exposure to the flavor (exposed vs. unexposed), nursery diet complexity (complex vs. simple), and flavor addition to the nursery diets (with vs. without flavor) as treatment factors. In Exp. 1, no differences in weaning weight (P > 0.53), total gain (P > 0.77), and ADG (P > 0.77) were observed between litters or pigs fed creep with and without the flavor. Flavor added to the creep feed did not influence total (P > 0.66) or daily (P > 0.66) creep feed intake of litters or the proportion of creep feed eaters (P > 0.41) in whole litters. In Exp. 2, a tendency for a 3-way interaction for ADG from d 5 to 10 (P 0.34) and pig BW (P > 0.45) in both periods post-weaning. Adding Luctarom to starter diets tended to improve ADFI (P < 0.06) during d 0 to 5. In conclusion, adding Luctarom to the creep feed did not affect litter creep feed intake, proportion of piglets consuming creep feed, and preweaning performance when creep was provided for 3 d before weaning. Pre-weaning exposure to Luctarom improved postweaning daily gain of pigs fed complex diets supplemented with the same flavor but did not influence performance of pigs fed simple diets

Effects of creep diet complexity on individual consumption characteristics and growth performance of neonatal and weanling pigs

In Exp. 1, 96 sows (PIC C29) and their litters were used to determine the effects of creep diet complexity on preweaning performance and the proportion of piglets consuming creep feed. The experimental treatments were: (1) no creep feed (n = 26), (2) simple creep diet (n = 26), and (3) complex creep diet (n = 44). Pigs fed the complex creep diet had greater (P < 0.03) ADG and tended to have greater (P < 0.06) total gain than pigs fed the simple creep diet, with no creep pigs intermediate. Litters fed the complex creep diet consumed twice the total (2.73 vs. 1.37 lb; P < 0.0006) and daily (0.91 vs. 0.45 lb; P < 0.0006) creep feed intake of litters fed the simple creep diet. The high-complexity creep diet improved (P < 0.0001) the proportion of eaters from 28% to 68%. A greater (P < 0.10) proportion of eaters were nursing in the middle and posterior teats (57% and 52%, respectively) than in the anterior teats (38%). In Exp. 2, 675 pigs from Exp. 1 (initial BW 14.1 lb and 21.2 ± 0.2 d) were used to determine whether social facilitation occurs between eaters and non-eaters in commercial nursery groups. The treatments were: non-eater group (pigs that were not provided any creep feed or non-eaters of creep feed), eater group (pigs that positively consumed creep feed), and mix group (pigs that were 51% non-eaters and 49% eaters). Each treatment had 25 pigs per pen and 9 replications (pens). In the initial 3 d postweaning, eaters had greater (P < 0.01) ADG and (P < 0.002) ADFI than non-eaters, with the mix group being intermediate. Overall ADG of the eater group was 6.2% higher (P < 0.05) than that of the non-eater group. For social facilitation to occur, weight gains of non-eaters in the mix pens should be either (1) closer to the weight gains of eaters in the mix pen or (2) greater than the weight gains of the non-eater group. Results showed that non-eaters within the mix pens failed both criteria. In conclusion, the high-complexity creep diet improved preweaning ADG, litter creep feed intake, and the proportion of eaters. Eaters had improved postweaning feed intake, daily gains, and weight uniformity and reduced postweaning lag. Mixing eaters with non-eaters within pens in large commercial groups did not stimulate feed intake and daily gains of non-eaters, which indicates that social facilitation did not occur

Effects of dietary astaxanthin on the growth performance and carcass characteristics of finishing pigs

A total of 48 barrows (initially 215 lb) were used to evaluate the effects of increasing dietary astaxanthin (0, 5, 10, and 20 ppm) on late-finishing pig performance and carcass characteristics. Pigs were blocked by weight and randomly allotted to 1 of 4 dietary treatments in a 26-d experiment. Pigs were fed simple corn-soybean meal-based diets. Treatments consisted of a control diet and the control diet with 5, 10, or 20 ppm added astaxanthin. For overall growth performance (d 0 to 26), ADG and F/G of pigs fed astaxanthin was not different from that of the control pigs. However, ADFI tended (linear; P < 0.10) to decrease with increasing astaxanthin. For the comparison of carcass characteristics, pigs fed increasing astaxanthin had decreased average (P < 0.03) and 10th rib (P < 0.06) backfat depth compared with control pigs. Pigs fed 5 or 10 ppm astaxanthin tended to have the lowest (quadratic; P < 0.10) 10th rib fat depth. Pigs fed increasing astaxanthin tended to have increased (quadratic; P < 0.10) standardized fat-free lean and percentage of fat-free lean, and pigs fed 5 or 10 ppm were the leanest. The loin muscle of pigs fed astaxanthin tended to have lower L* and b* (P < 0.06 and P < 0.08, respectively), indicating a darker color. The improved carcass characteristics of pigs fed astaxanthin resulted in a numeric increase in the net profit per pig for those fed 5 and 10 ppm astaxanthin. In conclusion, growth performance of pigs fed 5, 10, or 20 ppm astaxanthin was not different from that of pigs fed the control diet. However, the improved carcass characteristics could be economically beneficial to pork producers. Additionally, the improvements observed in loin color could result in improved consumer acceptance of fresh pork. These results warrant further research

Effects of lactation feed intake and creep feeding on sow and piglet performance

A total of 84 sows (PIC, Line 1050) and their litters were used to determine the effects of lactation and creep feeding on sow and piglet performance. Three groups of sows were blocked according to day of farrowing and parity and allotted to four treatments in a 2 × 2 factorial with lactation feed intake (ad libitum vs. restricted) and creep feeding (none vs. creep) as factors. Piglets were cross-fostered within each block to standardize litter weights and litter size (>11 pigs). A common lactation diet (1,586 kcal ME/lb, 0.97% TID Lys) was used in the study. From d 3 of lactation, ad libitum sows were allowed free access to feed while restricted sows were fed 25% less than those fed ad libitum. A pelleted creep diet (1,585 ME/lb, 1.56% TID Lys) with 1.0% chromium oxide was offered to creep-fed pigs from d 3 to weaning (d 21). Piglets were weighed individually at d 3, 7, 14, and 21. Amount of creep feed consumed was determined daily. Fecal samples from all creep-fed pigs were taken on d 7, 14, and 21 and fecal color was assessed to categorize pigs as eaters or non-eaters. Sow weight and P2 backfat thickness (6.5 cm from the midline over the last rib) were measured after farrowing and at weaning. There was no interaction between lactation feed intake and creep feeding. Ad libitum feeding of sows reduced BW loss (-33.0 vs. -52.9 lb; P0.30) sow BW and backfat loss, but increased days to estrus (5.4 vs. 4.9 d; P<0.03) for sows that returned to heat by 14 d. Creep feeding tended to improve litter weaning weights (132.7 vs. 124.9 lb/d; P<0.09) by reducing mortality rate after cross-fostering (3.9 vs. 7.3%; P<0.06). Total creep feed intake of litters did not differ (2.24 vs. 2.28 lb/litter; P<0.93) between ad libitum and limit-fed sows. About 60% of the creep-fed pigs were categorized as eaters. Of those identified as eaters, 23, 20, and 57% began consuming creep feeding from d 3 to 7, 7 to 14, and 14 to 21, respectively. From d 0 to 28 post-weaning, there was no effect of creep feeding on d 28 weights (P<0.93), ADG (P<0.86), ADFI (P<0.93), and F/G (P<0.95) compared to non-creep fed pigs. Eaters tended to be heavier until d 28 post-weaning (P<0.16) and had greater (P<0.06) ADG and total gains than non-eaters and no creep pigs. In conclusion, creep feeding improved survivability, but had no effects on pre-weaning gain and sow performance. Low feed intake during lactation negatively affected both sow and litter performance. Creating more eaters in whole litters may be beneficial in improving post-weaning performance

Effects of pcv2 vaccine on the growth performance of pigs and mortality rate in a pcv2-positive commercial swine herd

A total of 1,470 pigs were used to study a commercial sow herd with a history of Porcine Circovirus Disease (PCVD). The objective was to evaluate the effect of two commercially available Porcine Circovirus Type 2 (PCV2) vaccines on growth and mortality rates. The first vaccine was administered one week after weaning (1-dose) while the second was administered at weaning and repeated three weeks later (2-dose). A third group of unvaccinated pigs served as a control group. Pigs were individually weighed at weaning (d 0), d 113, 143, and just prior to market. On d 113, pigs on the 2-dose treatment were heavier (P<0.05) than the control group, and the 1-dose treatment pigs were intermediate. At d 143, just prior to when the first pigs were marketed, both the 1-dose and the 2-dose pigs were heavier than the control pigs by 7.6 and 10.2 lb (P<0.05), respectively, and there were no significant differences in weights between the two vaccinated groups. However, differences in weights between the vaccinated and the control pigs were smaller at off-test compared to differences at d 143 due to a wider variability in on-test days as a result of multiple marketing days prior to end of the trial. Although there were no significant differences between the two vaccinated groups, ADG was greater (P<0.05) in all vaccinated pigs compared to non-vaccinated control pigs from d 0 to d 113, d 143, and at off-test. From d 113 to 143 and until the day they were taken off test, there were no differences in ADG, regardless of treatment. This suggests that the increase in growth rate in vaccinated pigs occurred during the period d 0 to 113. Barrows consistently exhibited greater ADG and heavier weights (P<0.05) than gilts throughout the trial. No significant differences in mortality rate between treatments were observed but both vaccinated groups had mortality rates that were 3% lower than the non-vaccinated control pigs. Based on these results, both commercial vaccines were effective in mitigating the effects of PCV2 virus and improving the growth performance of pigs in a PCV2 positive herd