The issue of meat quality has grown to be of major concern in the swine industry. Cannon et al. (1995) reported that the condition referred to as pale, soft, and exudative (PSE) pork caused U.S. packers significant losses. It is well known that animal handling practices, pre-slaughter management, and genetic factors affect meat quality. However, there is little information available on the impacts of farm of origin and slaughter plant on pork quality. Thus, the objective of this experiment was to evaluate the influence of farm of origin and slaughter plant on pork quality while controlling genetic line, a major source of variation.

Present or impending restrictions on antibiotic usage in swine compel the industry to find alternatives that offer both performance enhancement and protection from disease. Bio-Mos®, derived from the cell wall of yeast, is a product that fits these criteria. The efficacy of Bio-Mos® as a growth promoter has been shown in the early stage of the nursery period (Miguel et al., 2002). The first few days post-weaning are critical. If producers are able to ease the pigs through this transition period with minimal stress, growth will not be compromised and the pig will be less susceptible to disease. Antibiotics are an effective solution to the common problems of weaning, but raise concerns related to development of antibiotic resistance. We need alternative solutions and Bio-Mos® may be one.

Facts, opinions and suggestions, however incomplete, have been gathered to prepare this review -- for several reasons: (1) I am probably the logical person to do it in that I served under Gene as an MS and Ph.D. student in the early 60s and later as a faculty member for 17 years during Dr. Becker's tenure as Head of the Department of Animal Sciences, (2) a detailed description of developments leading up to today's modern corn-soybean meal (SBM) diet has, to my knowledge, never been written, (3) it was arguably the most important development in the history of swine nutrition, (4) I admired Gene Becker as a scholar and leader -- and particularly for his tenacity and courage, and (5) several of my current colleagues in Animal Sciences encouraged me to undertake this task.

The use of artificial insemination (AI) has increased rapidly in commercial swine production. Extensive research has been conducted to optimize the reproductive potential of AI to equal or better that of natural insemination. Despite advances however, litter size and farrowing rate are less than optimal in most production systems (PigCHAMP, 2000). In an attempt to improve reproductive parameters in response to AI, considerable labor is performed to maintain boar contact during insemination. It has been shown that during courting, a mature boar produces derivatives of 16-androstene pheromones (Pearce and Hughes, 1987), which are found in the urine and saliva (Hughes et al., 1990). These pheromones were found to have a signaling function involved in stimulating puberty (Pearce and Hughes, 1987) and Mattioli et al. (1986) demonstrated that spraying 5a-androst-16-en-3-one in front of sows for 2 s, induced a rise in oxytocin. These reports suggest a role of the boar in altering the physiological response of the female. If pheromones emitted from the saliva and urine of boars influence the onset of estrus and oxytocin release, it could be hypothesized that these pheromones may also play a role in influencing sperm transport. Therefore, this study was conducted to test for the effect of boar contact during insemination on volume of semen and number of sperm expelled from the uterus following AI, and on fertilization rate and number of two-cell embryos. The results could provide information on the importance and necessity of providing boar stimuli during AI on quality of insemination, sperm transport, and fertility.

Due to the variation in body weight within a group of finishing pigs and the economic impact of marketing pigs outside the specified weight ranges of a particular slaughter plant, it is common practice to remove animals for market over a period of time. Conventionally, the heaviest pigs would be removed first thus allowing more time for the lighter pigs to reach an acceptable market weight. Research has shown that by removing 14-16% (Woodworth et al., 2000), or 50% (Bates and Newcomb, 1997) of the heaviest pigs from a pen, growth performance of the remaining animals is increased. However, little research is available that has evaluated removing different numbers of pigs from a group on the subsequent performance of the remaining animals. In addition, the factor(s) responsible for the increased growth response in the remaining animals in the pen have not been determined. Removing pigs from an established pen results in an increase in floor and feeder space for the remaining animals, but also changes the social dynamics of the group. The objectives of this study were to evaluate the effect of removing pigs from pens at differing rates and the effect of floor/feeder space post-removal on the subsequent growth performance of the remaining pigs.

The hexaphosphate form of inositol is the prototypical form of the phytate complex. The dephosphorylation of this complex by phytase is initiated at either the 3-position or the 6-position, of which the commercial phytases Natuphos® and Ronozyme®, respectively, are examples. Years of research have shown the efficacy of phytase, mainly Natuphos®, for releasing a portion of the phytate-bound phosphorus (P) in grain-oilseed meal diets fed to monogastric animals. Other supplements known to have phytate P releasing activity are citric acid (Boling et al. 2000) and either 1,25-dihydroxycholecalciferol or 1a-hydroxycholecalciferol (Edwards 1993; Biehl et al. 1995).

Early access to colostrum and absorption of immunoglobulins (Ig) are of vital importance to the survival, health and development of the newborn piglet. Piglets are born with very low Ig levels in their blood and require the Ig from colostrum to acquire passive immunity. The concentration of Ig in colostrum is highest at parturition and then decreases rapidly during the next 12 hours after farrowing (Jackson et al, 1995). Furthermore, the piglet is able to absorb Ig for only the first 24 to 36 hours of life. The qualitative and quantitative profiles of Ig isotypes in colostrum change during the post-farrowing period. The high concentrations of IgG (~100 mg/ml of IgG1 + IgG2) are necessary for successful transfer of passive immunity to the piglet (Curtis and Bourne, 1971). Immunoglobulin A, on the other hand, is present at lower concentrations (~10 mg/ml at farrowing) in colostrum compared to IgG. By about day 3 of lactation, IgA is the predominant Ig in sow milk at ~3 mg/ml (Curtis and Bourne, 1971).

The mammary gland is a relatively unique tissue in that it may undergo repeated cyclic phases of development, functional differentiation and regression. The carryover of mammary tissue from one lactation cycle to the next can vary considerably among sows, particularly considering the number of glands that they may have and the range of litter sizes. When a sow farrows, she has a set number of potentially functional mammary glands. That number defines the maximum number of glands that she would have throughout her farrowing cycles. However, the future potential productivity of each individual gland may be affected by the lactation function of that gland during the previous lactation cycle. The primary factor that determines how a gland functions during lactation is whether or not it is suckled. Does a gland being suckled or not suckled during one lactation impact its function in subsequent lactations? This paper discusses some of the aspects of porcine mammary gland growth and function that may help in addressing this question.

Loss of animals during transport to the slaughterhouse (dead on arrival and downers) and poor meat quality are interrelated issues resulting in significant losses to all sectors of the pig industry. Historically, a major cause of these losses could be attributed to the halothane gene, however, substantial losses also can occur in halothane negative population (Channon et al., 2000; Miller et al., 2000). Occurrence of downers is associated with stress leading to high blood lactate and metabolic acidosis (Ivers et al., 2002). This metabolic condition also can compromise meat quality when it occurs immediately before slaughter. Some of the factors associated with stress and elevations in blood lactate are physical exercise (van den Hende et al., 1970), electric stimulation (Bickhardt and Wirtz, 1987), or both (Bertol et al., 2002), which are factors commonly experienced by pigs during handling. Therefore, approaches that reduce metabolic acidosis during physical and emotional stress are practically important. Reduction in lactate production by reducing glucose and increasing fatty acid utilization as the energy substrate could be one way to address this problem.

Addition of estrogens (Claus et al., 1989), PGF2a (Henze and Jurk, 1986, Pena et al., 2000), and oxytocin (Baker at al., 1968, Pena et al., 1998) to boar semen has been used to improve reproduction with AI. Estrogens are present in high concentrations in boar semen (Claus et al., 1990) and have been shown to stimulate myometrial contractions (Langendijk et al., 2002a) by causing release of PGF2a from the endometrium (Claus et al., 1987). The addition of PGF2a to semen is reported to increase litter size, farrowing rate (Henze and Jurk, 1986; Pena et al., 2000), and myometrial contractions (Langendijk et al., 2002a) but the results have not always been consistent (Flowers and Esbenshade, 1993). Supplementation of oxytocin to semen has also increased farrowing rates in some cases but this effect was also inconsistent (Flowers and Esbenshade, 1993). However, Pena et al. (1998) reported that litter size and farrowing rates were improved by oxytocin during the periods of seasonal infertility in the summer months. Collectively, the impact of the addition of these hormones to semen yielded inconsistent results, which has raised the question of the need, efficacy, and mechanism of action for these hormones for improving fertility with AI.

Very little research has been attempted to determine isoleucine (Ile) requirements of late-finishing pigs. Variability in these rapidly growing animals makes interpretation of results a very difficult task. Attempts to minimize variability by using short-term feeding assays have resulted in trials that utilize minimum plasma urea-nitrogen as an indicator of the requirement (Liu et al., 2000a). Other research by Liu et al. (1999) has shown that reducing protein level and adding amino acids (AA) does not affect growth performance of early- or late- finishing pigs. Their results have also suggested that Ile is a limiting AA for late-finishing barrows fed AA-fortified, low-protein corn diets (Liu et al., 2000b). When diets (7.1% CP) comprised of corn (supplemented with synthetic L-lysine, L-threonine, L-tryptophan and DL-methionine) were fed to late-finishing pigs, growth responses to supplemental Ile were observed. This suggests that Ile may become a limiting AA for late-finishing pigs fed low-protein diets. Therefore, it is important to determine the Ile requirement of late-finishing pigs.

Modern pig housing systems are expensive to construct and operate. Therefore, it is of considerable economic importance to maximize the utilization of floor space by increasing the pounds of pork produced from a facility. A considerable amount of research has been carried out investigating the relationship between floor space and pig performance (Kornegay and Notter, 1984). However, the majority of the previous research was carried out in traditional multi-stage systems (McGlone and Newby, 1994) or with small group sizes (Gonyou and Stricklin, 1998) that are not typically used in modern commercial pig production (Wolter et al., 2001). Recently, the pork industry has seen the implementation of single-stage wean-to-finish production systems. Therefore, the objective of this research was to investigate the impact of group size/floor-space allowance in a single-stage wean-to-finish production system under commercial conditions.

When voluntary feed intake is at a level that does not provide sufficient amino acids and energy for milk synthesis, the lactating sow compensates by mobilizing protein and fat from body tissues to provide additional amino acids, glucose and energy needed to sustain milk production (Mullan and Williams, 1990; Pettigrew et al., 1992a,b; Sauber et al., 1998; McNamara and Pettigrew, 2002a,b). A balance of nutrients must be provided to support the demand for milk production by the litter and to minimize weight loss in lactation. Therefore, knowledge of the balance of amino acids and level of energy required to maximize efficiency of milk production and minimize body weight loss is needed to provide optimal nutrition for the lactating sow.

AI success can depend upon sperm quality at collection, sperm age when inseminated, insemination volume, and AI times relative to estrus. However, in addition to these factors, another essential component of AI effectiveness is the number of sperm inseminated. In fact, concentration of sperm inseminated, may actually compensate for many deficiencies involving the technology when using AI, when conditions are less than optimal. Therefore, properly estimating the concentration of the boar ejaculate is critical for efficient boar use and for influencing the effectiveness of the AI technology to optimize farrowing rate (FR) and litter size (LS).