Swine Day, 1989
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Item Open Access New concepts in breeding barn design(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:49:43Z) Levis, D.G.Many existing swine breeding facilities have been designed to control the environment, provide continuous boar-sow contact for stimulating recently weaned sows to cycle, reduce the distance a weaned sow or boar has to be moved for mating, and reduce construction costs by not constructing breeding pens to be used only for mating. Pork producers operating these types of facilities have had problems with efficiency and accuracy of estrous detection, low percentage (70%) of sows bred twice, slick breeding floors, and excessive labor requirements. A breeding facility should be arranged so the work routines, such as estrous detection; moving, mating, and feeding animals; and recording breeding information arc easily, quickly, and safely performed. Remember, tasks that are difficult to do may never be done.Item Open Access Maximizing farrowing rate(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:49:13Z) Levis, D.G.Farrowing rate can be defined as: 1) the number of mated females that farrow within a contemporary group per total number of MATED females for this group or 2) the number of females that farrow within a contemporary group per total number of EXPOSED females for this group. Generally, the first definition is used when hand-mating, whereas the second definition has to be used when pen-mating. Regardless of the definition, farrowing rate can be maximized only by taking total control of the breeding herd. High farrowing rates will result when fertility is high in boars, sows, and gilts; however, excellent management must be used to maintain high fertility in males and females. North Carolina State University data have shown a high correlation between farrowing rate and live pigs born per bred sow per year (Figure 1). Their data show that for each 10% increase in farrowing rate of bred sows, there is a corresponding increase of 2.63 live pigs born per sow per year. In light of these data, pork producers should strive to maximize farrowing rate. This can be done by providing good management during prebreeding, breeding, and gestation phases. The purpose of this article is to provide information on possible management practices to use during each of these phases.Item Open Access Hydrocortisone acetate-injected piglets have a larger pancreas and greater mucosal weight and lactase, maltase, and sucrose activities in the duodenum(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:48:47Z) Kreikemeier, K.K.; Harmon, D.L.; Nelssen, Jim L.; jnelssenOne litter of 12 piglets was used in a completely random design to evaluate the effects of hydrocortisone acetate injections on organ weight and carbohydrase activities. Dams' milk was the only food source available to the piglets. When they were 7 d old, six pigs were injected with hydrocortisone acetate (50 mg/kg BW; 50 mg/ml) and six others were injected with an equal volume of saline (1 ml/kg BW). When the pigs were 14 d old, tissues were collected, weighed, and analyzed for carbohydrase activities. Hydrocortisone acetate injection had no effect on pig daily gain (d 7 to 14), liver weight, spleen weight, or small intestinal (SI) length. However, it did increase pancreatic weight by 29%. Consequently, total pancreatic alpha-amylase was 38% greater in hydrocortisone-injected pigs. Hydrocortisone also increased duodenal mucosal weight (per cm of SI) by 23%, duodenal lactase activity (per cm of SI) by 44%, duodenal maltase activity (per cm of SI) by 163% and duodenal sucrase activity (per cm of SI) by 214%. There was little effect on disaccharidase activities in the jejunum or ileum. We conclude that hydrocortisone acetate may be useful to stimulate pancreatic growth and duodenal mucosal weight as well as lactase, maltase, and sucrase activity in 7-d-old pigs.Item Open Access The reaction of slaughter hog cash and futures prices to USDA hogs and pigs reports(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:48:04Z) Schroeder, Ted C.; Mintert, J.R.; Blair, John M.; tcs; jmintertThis study examined the reaction of slaughter hog cash and futures prices to USDA Hogs and Pigs reports. Over the 1972-87 period, the nearby live hog futures price had $1/cwt or larger absolute price changes on 48% of the trading days immediately after the Hogs and Pigs report release compared to 6% of the days of the release, suggesting that the reports arc providing important new information to the market. Average price moves in cash and futures markets following the report releases were positive, suggesting that price usually increased the day after the reports. Over the 1972-87 period, the cash price declined on only 38% of the first trading days after the report releases, and the futures market price declined on 43%. The day of the week on which the Hogs and Pigs reports were released had no significant impact on the market's price variability following release.Item Open Access Growth response to dietary additions of bacillus subtilis from weaning to 230 pounds(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:46:52Z) Swanson, J.A.; Hancock, Joe D.; jhancockTwo hundred fifty-five pigs, weaned at 4 wk of age, were used in an experiment to compare the efficacy of Bacillus subtilis and antibiotics as growth promoters for swine from nursery to finishing. Treatments were a nonmedicated control; B. subtilis added at 5 x 105, 1 X 106, or 5 x 106 CFU/g feed; or antibiotics (50 g/ton carbadox during the nursery phase and 100 g/ton chlortetracycline in the growing and finishing phases). Average daily gain and average daily feed intake were greater for pigs fed antibiotics in the nursery and grower phases than for pigs fed diets containing no medication or diets containing B. subtilis. Feed to gain ratio was not affected by the addition of B. subtilis or antibiotics. In the finishing phase, feeding B. subtilis and antibiotic did not affect avg daily gain, avg daily feed intake, or feed to gain ratio. From weaning to market weight, avg daily gain and avg daily feed intake were greater for pigs fed antibiotics than pigs fed the other treatments. Our results indicate that at the levels used in this experiment, feeding B. subtilis is not as effective as feeding antibiotics to improve performance of nursery and growing pigs. Neither B. subtilis nor chlortetracycline affected the performance of finishing pigs.Item Open Access The effect of dietary energy density and porcine somatotropin on apparent digestibility and retention of nutrients in finishing swine(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:46:29Z) Stoner, G.R.; Schricker, B.R.; Nelssen, Jim L.; Goodband, Robert D.; Hines, Robert H.; jnelssen; goodbandSixteen barrows were used in a metabolism study (avg wt of 101.2 lb) to evaluate the effect of dietary energy density and porcine somatotropin (pST) on apparent digestibility and retention of nutrients in finishing pigs. This study was designed as a split-plot with 4 mg pST/d or placebo injection as whole plot treatments and four dietary energy densities (1.37, 1.48, 1.60, and 1.71 Meal ME/lb) and period as the subplot treatments. Increasing dietary energy density increased apparent digestibility of dry matter, gross energy, and nitrogen, but had no effect on nitrogen retention. Porcine somatotropin administration had no effect on apparent digestibility of nutrients; however, percentage nitrogen retention was increased 42% compared to control pigs.Item Open Access Relationships between ovulation rate and litter size for flushed and nonflushed gilts(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:46:01Z) Rhodes, M.T.; Davis, Duane L.; Stevenson, Jeffrey S.; davis; jssWe examined the effects of flushing (3.4 lb additional ground milo for approximately 2 wk before insemination) and pubertal status (inseminated at puberty or postpuberty) on ovulation rate and litter traits in gilts. Hushing resulted in 1.1 more eggs released at ovulation and 1.3 more pigs/litter. The response in litter size occurred primarily among gilts inseminated at their pubertal estrus. Neither flushing nor pubertal status affected prenatal survival. Data for 58 gilts were used to evaluate the relationship between ovulation rate and litter size. Litter size increased linearly with increased ovulation rate to a maximum of 13 pigs when 19 eggs were released at ovulation. We conclude that ovulation rate limits litter size for gilts inseminated at puberty, because their unstimulated ovulation rate does not fully utilize the reproductive potential of their uterus. It appears that litters of 12 to 13 pigs are possible, but we have not been successful in increasing the average litter size in postpubertal gilts beyond 10 to 11 pigs, because our flushing treatment produced only a modest increase in ovulation rate of postpubertal gilts.Item Open Access The genetics of lean growth(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:45:17Z) Nichols, David A.; dnicholsIn recent years, the pork industry has faced numerous challenges. As consumer resistance to fatter meats has increased, the industry has had two options, 1) argue against popular opinion that fat consumption posed a health risk or 2) strive to reduce the fatness of their products. Since the first option is highly unlikely, the NPPC and commodity leaders have moved rapidly, decisively, and aggressively to promote and reposition pork as a vital, healthful part of the U.S. diet. Pork consumption from 1965 to 1985 was reasonably stable (1965, 45 lb; 1985, 44.2 lb). Demand has been stable to declining in recent years. However, Glenn Grimes, University of Missouri economist, says pork consumption increased about 3% last year, despite higher prices and stiff competition. Certainly, pork producers can be proud of what has been accomplished, but to be certain that pork remains competitive, progress must be made in reducing fatness of the pork carcass. Additional concerns for the industry are uniformity of the product, convenience for the consumer, and price competitiveness. New buying systems encourage production of lean, uniform lots of market hogs, often at heavier weights than in previous years. For many producers, this may require a change in breeding and production systems.Item Open Access The effect of dietary energy density on growth performance of finishing swine treated with porcine somatotropin(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:44:53Z) Stoner, G.R.; Schricker, B.R.; Nelssen, Jim L.; Goodband, Robert D.; Hines, Robert H.; jnelssen; goodbandA growth study (60 barrows averaging 125.4 lb) was conducted to evaluate the effect of dietary energy density on growth performance of finishing pigs treated with porcine somatotropin (pST). Barrows were blocked on weight and allotted randomly to pens (2 barrows/pen, 5 pens/treatment). Barrows were injected daily with 4 mg pST and fed six experimental diets with four energy densities (1.37, 1.48, 1.60, or 1.71 Meal ME/lb) and four lysinc:energy ratios (4.0, 3.7, 3.4, or 3.2 g lysine/Mcal ME). Diets were formulated to contain at least 200% of NRC (1988) recommendations for essential nutrients. Increasing dietary energy density and adjusting the lysine:energy ratio to maintain 3.4 g lysine/Mcal ME decreased average daily feed intake and improved feed efficiency, but did not affect average daily gain. Increasing dietary energy density without adjusting the lysine:energy ratio increased average daily gain, decreased average daily feed intake, and improved feed efficiency linearly. These results indicate that finishing pigs injected daily with 4 mg pST and consuming 30 g lysine per day require approximately 9 Meal ME per day to optimize growth performance and efficiency.Item Open Access Space requirements of finishing pigs fed to an average pen weight of 250 pounds(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:44:14Z) Nicholson, R.I.; Fitzner, G.E.; Nichols, David A.; Hancock, Joe D.; Hines, Robert H.; Goodband, Robert D.; Nelssen, Jim L.; goodband; jnelssen; dnichols; jhancockSpace allowances of 6, 8, 10, and 12 ft^2 were evaluated for pigs fed from 130 lb to a pen average of 250 lb. Average daily gain and average daily feed intake. increased linearly (P<.05) as space allowance increased. However, those pigs permitted 10 or 12 ft^2 of space were similar in avg daily gain, avg daily feed intake, and feed efficiency, suggesting that 10 ft^2 of space is adequate for feeding finishing hogs to a heavier average pen weight. Coefficients of variation (CV) for initial weight and final weight were increased for pigs with 6 ft^2, whereas for those exposed to 10 and 12 ft^2, the CV was reduced, indicating more uniform pigs at final weight with greater space allowance.Item Open Access Porcine somatotropin and dietary lysine influence bone mineralization and mechanical properties in finishing swine(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:43:48Z) Schricker, B.R.; Goodband, Robert D.; Hines, Robert H.; Nelssen, Jim L.; Kropf, Donald H.; Hancock, Joe D.; goodband; jnelssen; dkropf; jhancockThe femur, a rib, and third phalanx of the second digit from the front foot were collected from 108 barrows (initial wt = 125 lb) and analyzed to determine the effects of porcine somatotropin (pST) and dietary lysine on bone mineralization and mechanical properties. In Exp. 1, pigs were injected daily with 4 mg pST and fed diets containing .6, .8, 1.0, 1.2, or 1.4% lysine; 1.0% Ca; and .8% P. Control pigs (placebo injection) received the .6% lysine diet. Bone wall thickness (BWT) of the femur increased but ash content decreased as dietary lysine level increased. Stress values and ash content of the rib also decreased with increasing dietary lysine level. In Exp. 2, pigs were injected with either 4 or 8 mg/d pST and fed diets containing .8, 1.0, 1.2, or 1.4% lysine; 1.1% Ca; and 1.0% P. Control pigs received the .8% lysine diet. Increasing pST dosage increased BWT of the femur, but decreased ash content. In the rib, increasing pST dosage reduced stress values, modulus of elasticity, and ash content. Increasing lysine level resulted in increased BWT of the femur and decreased ash content of rib, femur and phalanx. These data indicate that pST administration in conjunction with increasing lysine levels decreases bone mineralization but increases BWT of finishing pigs.Item Open Access Will porcine somatotropin (pST) lower pork quali1y?(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:35:39Z) Hunt, Melvin C.; Whipple-Van Patter, G.; Klemm, R.D.; Schricker, B.R.; Goodband, Robert D.; Nelssen, Jim L.; Hines, Robert H.; Kropf, Donald H.; hhunt; dkropf; goodband; jnelssenThe types and diameters of muscle fibers from 30 barrows that had received daily injections of porcine somatotropin (pST) or a placebo and were fed dietary lysine at .6, .8, 1.0 or 1.2% were determined. Fiber data indicated that pST slightly increases the anaerobic metabolic potential of longissimus muscle. The higher levels of lysine caused enlargement of muscle cells. Earlier research has shown that this type of muscle biochemistry contributes to development of PSE muscle. Thus, use of pST in certain strains of pigs may lead to reductions in muscle quality.Item Open Access Using immunological criteria to predict utilization of soybean proteins by the early-weaned pig(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:35:14Z) Li, D.F.; Reddy, P.G.; Blecha, Frank; Klemm, R.D.; Nelssen, Jim L.; Goodband, Robert D.; Hancock, Joe D.; jnelssen; blecha; jhancock; goodbandTwo trials were conducted to determine the suitability of soybean products for baby pigs. For trial 1, 40 weanling pigs were orally infused with .01 lb/pig/d of either dried skim milk (control), soybean meal (48% CP), soy protein concentrate, extruded soy protein concentrate, or soy protein isolate from d 7 to 12 of age, weaned at 21 d of age, and fed a diet containing the corresponding protein source until d 7 postweaning. Sows were fed a corn-corn gluten meal-based diet supplemented with lysine and tryptophan to avoid exposure of pigs to soybean proteins. All pigs were sacrificed at 28 d of age. In Trial 2, 48 pigs were utilized, with preweaning treatments identical to those in Trial 1 except the soy protein isolate was not used as a treatment. They were fed a diet containing the same protein source for 2 wk postweaning, then fed a common diet with 4% soybean oil and 1.25% lysine for 3 wk. Growth performance was measured. Results indicated that pigs fed diets containing soybean meal had lower villus height and rate of gain than pigs on any other treatments. There were no differences in villus height and crypt depth among soy protein concentrate, extruded soy protein concentrate, and soy protein isolate. In the growth trial, pigs fed the diet containing extruded soy protein concentrate had the highest ADG compared to other soybean products tested. Decreased villus height and increased serum anti-soy IgG titers, coinciding with inferior performance and presence of residual antigenic protein in the digestive tract of baby pigs fed soybean meal, indicate that conventionally processed, commercial soybean meal retain antigens that cause immunological changes in early-weaned pigs.Item Open Access Improved pork products for the 1990's(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:34:41Z) Kropf, Donald H.; dkropfThe word "improved" in a commercial sense means "altered product characteristics to meet the consumers' real and perceived needs." The pork industry in the 90's must progress toward offering products designed to meet consumer demands instead of saying "this is what we are producing and you'd better buy it." For the pork producer, "improved" means those products that will. increase pork sales. We must realize that the primary nutritional contributions of pork to human diets will be protein and vitamins, especially B-vitamins. Perhaps we should emphasize these more in our advertising, but good flavor, low fat, low salt, and convenience are likely the selling points to be emphasized. Perhaps we also can stress the desirability of other features of new pork products developed in the 90's, such as added dietary fiber or the advantage of pork fat in having a more desirable ratio of polyunsaturated/monounsaturated fatty acids in relation to saturated fatty acids than other animal fats and some plant fats.Item Open Access The effects of excess dietary lysine additions on growth performance and carcass characteristics of finishing pigs(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:34:27Z) Stoner, G.R.; Goodband, Robert D.; Hines, Robert H.; Nelssen, Jim L.; Kropf, Donald H.; goodband; jnelssen; dkropfSeventy-five barrows (initial wt 136 lb) were utilized to evaluate the effects of dietary lysine levels ranging from .6 to 1.4% on growth performance and carcass characteristics. Pigs were fed a pelleted corn-sesame meal diet containing .6% lysine (17.7% crude protein) or diets containing .8, 1.0, 1.2, or 1.4% lysine provided by L-Iysine HCl. All other amino acids, vitamins, and minerals were calculated to be at least double the pig's requirement (NRC, 1988), to ensure that no nutrient other than lysine would limit performance. When the pen mean weight reached approximately 235 lb, six pigs per treatment were slaughtered, and carcass data were collected. Increasing dietary lysine level resulted in no differences in average daily gain, feed intake, or feed efficiency. Furthermore, increasing lysine level had no effect on longissimus muscle area, average backfat thickness, loin weight, kidney fat weight, or percentage muscle. However, pigs fed .8% lysine had slightly less backfat and greater percent muscle than pigs fed .6% lysine. These data indicate that dietary lysine additions above .6% do not improve growth performance of finishing barrows; however, increasing the lysine level to .8% may slightly improve carcass leanness.Item Open Access Nutritional considerations for improved lean value(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-15T21:34:05Z) Nelssen, Jim L.; jnelssenThe swine industry is in a transitional period as it gears up to produce the lean meat required by the consumer. In fact, pork processors arc increasing the production of lean products (boneless loins, 95% fat-free hams) because consumers are willing to pay premiums for low-fat products. New methods of measuring the amount of lean pork (fat-a-meter, etc.) are being developed rapidly, in order to allow the packer to offer price differentials for lean compared to fat pigs. Pork producers, in my opinion, will adjust production systems to meet consumer demands for lean pork when monetary differentials are offered by the packer for high lean-value carcasses.Item Open Access Effect of heat treatment on the nutritional value of low-inhibitor soybeans for nursery growing, and finishing pigs(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-09T15:35:17Z) Lewis, A.J.; Giesemann, M.A.; Nelssen, Jim L.; Hancock, Joe D.; jhancock; jnelssenTwo hundred forty nursery pigs (12.8 lb initial wt) were used in a 28-d growth assay to determine the nutritional value of Williams 82 soybeans with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Treatments were soybean type (+K and -K) and heat treatment (none, half-roasting, and full-roasting time), in a factorial arrangement. The soybeans were heated in a Roast-a-Tron roaster, ground, and added to corn-dried whey diets formulated to be limiting in lysine (.88%). Pigs fed diets with -K soybeans gained 21% faster and were 13% more efficient than pigs fed diets with + K soybeans. As heat treatment was increased to full-roasting, rate and efficiency of gain increased. The + K soybeans were of lower nutritional value than the - K soybeans when fed raw or half-roasted, but the two soybean types were of similar nutritional value when fully roasted. Two additional experiments (66 individually fed pigs each) were conducted using growing and finishing pigs. The soybeans were added to corn-based diets formulated to contain .60 and .48% lysine for the growing and finishing phases, respectively. Growing pigs fed diets with the - K soybeans gained 10% faster, were 10% more efficient, and had 13% lower fat depth at the last rib than pigs fed the + K soybeans. Finishing pigs fed diets with the - K soybeans were more efficient and had lower fat depths than pigs fed the +K soybeans. Considering all three growth phases, the low-inhibitor (-K) soybeans were of greater nutritional value than the conventional (+ K) soybeans, with the greatest difference observed when the soybeans were fed raw. The nutritional value of both soybean types (+K and - K) was optimized with full-roasting. The half-roasting treatment was not sufficient to optimize the nutritional value of the low-inhibitor soybeans.Item Open Access Effect of fat combinations on starter pig performance and nutrient digestibility(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-09T15:35:00Z) Li, D.F.; Harmon, D.L.; Fitzner, G.E.; Jones, D.B.; Nelssen, Jim L.; Goodband, Robert D.; jnelssen; goodbandA growth trial was conducted to evaluate the effects of addition of soybean oil, coconut oil, 50% soybean oil: 50% coconut oil, 75% soybean oil: 25% coconut oil, and 25% soybean oil: 75% coconut oil on starter pig performance and nutrient digestibility. Diets were supplemented with 10% fat for the first 2 wk of the study and 5% for the final 3 wk. Fecal samples were collected from pigs by rectal massage, and apparent digestibility of DM, N, total fat, and fatly acids were calculated using chromic oxide (.3%) as an indigestible marker. Results demonstrated that ADG and feed efficiency (F/G) were improved by fat additions, with 50% soybean oil and 50% coconut oil maximizing performance. Pigs gained faster on the soybean oil and coconut oil combinations than on coconut oil and consumed more of the soybean oil plus coconut oil diet than either coconut oil or soybean oil diets. No differences were observed for apparent digestibility of fat and GE or ileal digestibility of DM and N among the fat sources. However, pigs fed the combination of soybean oil and coconut oil tended to have improved ileal digestibility of medium chain fatty acids (< 14 C). These trials demonstrate that a combination of soybean oil and coconut oil improves pig performance and tends to improve apparent digestibility of medium chain fatty acid compared to pigs fed diets containing either no added fat or soybean oil or coconut oil alone.Item Open Access Effect of microbial inoculants on the storage characteristics and nutritional value of high moisture corn for finishing pigs(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-09T15:34:48Z) Bolsen, K.K.; Jones, D.B.; Hines, Robert H.; Hancock, Joe D.; jhancockHigh moisture corn (23% moisture) was harvested in September, 1988, and stored in concrete silos until March, 1989. As the corn was harvested, it was divided into four treatment silos: high moisture corn (HMC) and HMC treated with inoculants containing lactobacillus, serratia, or streptococcus organisms. As a positive control, some of the corn was allowed to "field dry" to 14% moisture before being harvested. Two hundred forty finishing pigs were fed the com treatments. Approximately mid-experiment, samples of the corn and mixed diets were collected and evaluated for aerobic stability. At the end of the experiment, chromic oxide was added to the diets (.25%), and the indirect method was used to calculate apparent dry matter and nitrogen digestibilities. Results from the experiment indicated that the mixed diets were stable for a longer period of time than the ground corn (132 h vs 103 h until heating occurred). The HMC treatment was the least stable, and lactobacillus-treated corn was less stable than corn treated with the serratia and streptococcus inoculants. Also, corn treated with the serratia inoculant was more stable than corn treated with the streptococcus inoculant. Average daily gain of pigs was not affected by corn treatment. There were no differences in dry matter intake or feed efficiency expressed on a dry matter basis. Apparent digestibilities of dry matter and nitrogen were similar among the treatment groups. From these data, we conclude that new experimental inoculants (serratia and streptococcus) improve the storage characteristics of high moisture corn. However, an improvement in storage characteristics does not necessarily indicate improved nutritional value of the treated corn.Item Open Access Effect of lysine level and supplemental soybean oil fed during lactation on sow and litter performance through two parities(Kansas State University. Agricultural Experiment Station and Cooperative Extension Service, 2010-04-09T15:34:36Z) Weeden, T.L.; Thaler, R.C.; Li, D.F.; Fitzner, G.L.; Nelssen, Jim L.; Hines, Robert H.; jnelssenA total of 158 gilts were fed ad libitum one of the following four diets during lactation: .65% lysine, .75% lysine, .65% lysine + 3% soybean oil, and .75% lysine + 3% soybean oil. These same sows were carried through a second parity on the same lactation diet treatments. In parity 1, lysine level had no effect on feed intake or interval from weaning to estrus. Addition of 3% soybean oil increased the weaning to estrus interval and decreased feed intake, although caloric intake was not different. In parity 2, there was no effect on feed intake from 3% supplemental soybean oil; however, the weaning to estrus interval was still delayed by 2.5 d. Overall, there were no interaction effects from increasing the lysine level and adding 3% soybean oil. Increasing lysine to .75% and adding 3% soybean oil had no effect on sow weight loss, sow backfat loss, pig survivability, litter size at weaning, litter weight at weaning, or average pig weight at weaning. Based on the results of this experiment, it appears that a .65% lysine diet without supplemental fat is adequate during lactation.
