Doctor of Philosophy / Department of Animal Sciences and Industry / Robert D. Goodband / Michael D. Tokach / The dissertation consisted of 6 chapters involving studies in heavy weight market pig production, dietary Ca and P requirements for nursery pigs, antimicrobial resistance development in finishing pig microbiota, seasonal growth variability in commercial pig production, and leftover feed management in wean-to-finish pig productions. The first chapter presents a thorough review of published studies involving genetic selection, nutritional requirements, health, welfare, and pork quality of finishing pigs with marketing weight greater than 130 kg and assessed future research needs. Chapter 2 describes 2 experiments that evaluated the growth performance and percentage bone ash of early nursery pigs fed various combinations of Ca and P provided by inorganic sources or phytase. Feeding more than 0.90% dietary Ca decreased average daily gain (ADG), average daily feed intake (ADFI), gain:feed ratio (G:F), and percentage bone ash when diets were at or below NRC (2012) requirement for standardized total tract digestible (STTD) P. However, adding inorganic P or phytase to P deficient diets improved pig performance and alleviated the negative impacts of high dietary Ca concentration on growth performance. The experiment presented in chapter 3 characterized the dose-response to increasing digestible P in diets without or with 2,000 units of phytase for 6- to 13-kg pigs. Increasing STTD P from 80 to 140% of NRC (2012) requirement estimates in diets without phytase, and from 100 to 170% of NRC (2012) in diets with phytase, improved ADG, G:F, and percentage of bone ash. Estimated STTD P requirements varied depending on the response criteria and statistical models and ranged from 91 to >140% of NRC (2012) in diets without phytase, and from 116 to >170% of NRC (2012) for diets containing phytase. In addition, phytase exerted an extra-phosphoric effect on promoting pig growth and improved the P dose responses for ADG and G:F. In chapter 4, a study was conducted to determine the effects of tylosin administration route (through feed, drinking water, or intramuscular injection) on the growth performance and the development of antimicrobial resistance in fecal enterococci of finishing pigs. Pigs that received tylosin injection had decreased ADG and G:F compared with control pigs that did not receive any antibiotic treatment, which may be due to a stress response to the handling during injection administration. Moreover, tylosin administration via injection and feed resulted in a higher probability of enterococcal resistance to erythromycin and tylosin compared with drinking water treatment. Chapter 5 presents a retrospective analysis on the seasonal growth patterns of nursery and finishing pigs in 3 commercial production systems located in the Midwest US. Nursery ADG and ADFI expressed prominent seasonal variations and were similar among systems, whereas nursery G:F was not affected by season. Finisher ADG, ADFI, and G:F varied over seasons, but the magnitudes and patterns of change were system dependent. This chapter also presents the concepts underlying the implementation of a multi-level linear mixed model of production records to analyze seasonality and potentially other decision factors in commercial systems. Finally, in chapter 6, 2 experiments were conducted regarding the strategy of managing leftover finisher feed in a wean-to-finish production system. Experiment 1 evaluated the timing (phase) of feeding 2.5 kg/pig of finisher feed in a 5-phase nursery program. All growth responses decreased immediately when the finisher feed was blended into nursery diets; however, pigs greater than 11 kg (phase 3) had improved ability to compensate for the negative effects of finisher feed on overall growth performance. Experiment 2 was then carried out to investigate the maximum amount of finisher feed can be fed to 11-kg pigs. Increasing the finisher feed budget from 0 to 3.75 kg/pig resulted in a linear decrease in ADG and ADFI. However, the economic analysis indicated no change in income-over-feed-cost due to the timing and dose of blending finisher feed into nursery diets.

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The objectives of this research were to determine the net energy (NE) of dry extruded expelled soybean meal (DESBM) using an indirect calorimetry (IC) in growing pigs, to determine the effect of multi-enzyme supplementation on the NE content of DESBM fed to growing pigs and to validate the NE system for feed formulation. In Exp 1, the values obtained with the IC method were consistently greater than those obtained with prediction equations. The discrepancy between the determination technique used was about 1% when diets were formulated with a constant protein content or corn:soybean meal ratio (1.0% and 0.7%, respectively), however, this was 4.1% when diet was formulated with simple substitution technique. Thus the NE value of DESBM was evaluated to be 2,548 kcal/kg DM when diets were formulated on a constant ratio between the other energy yielding components. In Exp 2, addition of enzyme increased the NE value of both the diet and the test ingredient; DESBM. Supplementation with multi-enzyme complex (Superzyme-OM, Canadian Bio-System Inc., Calgary, Canada) at 0.05% and 0.1% of the diet improved NE values of DESBM by 4.9 % and 3.7%, respectively. In Exp 3, the results indicate a better growth performance (ADG and G:F) when diets were formulated on NE basis compared to the DE system of diet formulation. Moreover addition of enzyme improved the performance for the NE system of diet formulation

This thesis examines the activities of four groups of four sows, allocated to one of two space allocations, in a novel farrowing system design, over parturition and during lactation. The two pen configurations provided 13.4m² (L) and 8.6m² (S) per sow, respectively. A lactation diet providing 14MJ/kg DE and 18% CP was supplied ad libitum via a sow operated feeder, adapted to facilitate the calculation of individual feed intakes. The influence of environmental, physical, management and production factors upon the way in which sows allocated their time to different activities, suckling behaviour, feed intakes and feeding and drinking strategies was investigated. Sows in the small pen area were generally less active than those housed in the large pen configuration. During the first week of lactation, significantly more time was spent lying down (P<0.05) and fewer transitions were made between postures (P<0.001) in the reduced space allocation. Sows in the S pen configuration suckled their piglets significantly more frequently than sows in the L pen area (P<0.001). However, similar daily piglet weight gains were achieved in both the L and S pen configurations. Daily feed intakes of 7.69 kg (s.e. 0.31) and 7.72 kg (s.e. 0.35) were achieved during lactation, by sows in the L and S pen configurations, respectively. This was accomplished by sows taking a series of small feeds throughout the day. Sows in the S pen area made fewer visits to the feeder and spent less time per day feeding, compared with sows in the L pen area. However, more feed was consumed per visit by the S sows, resulting in similar daily feed intakes in both treatment groups. A marked increase in activity during the 24 hours prior to parturition was followed by a sharp reduction during day 1 of lactation in both treatment groups. Thereafter, activity levels increased gradually during week 1 of lactation. Most piglet deaths occurred in early lactation, 65.0% and 67.9% of which were during days 1 to 3 following birth in the L and S pen areas, respectively. Mortality of live-born piglets was unacceptably high at 19.6% in the L and 24.6% in the S pen areas. The relative advantages and disadvantages to sows and piglets within the novel farrowing system are considered in the general discussion.

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Measures of production, physiology, behaviour and pathology were used to assess the effects of confined and loose dry sow and farrowing housing systems on the welfare of the sow and her litter. Litter size decreased and piglet mortality increased greatly after the sixth parity, regardless of housing system, resulting in a sharp decline in the number of piglets weaned per litter. Stall-housed sows gave birth to the most piglets per sow per year, but also had the highest piglet mortality. Overall, piglet mortality was higher in farrowing pens than in crates. Sows from the large group had a significantly larger number of returns to service after farrowing in crates. Behaviourally, all sows adapted well to the farrowing house. All sows showed an increase in the number of posture changes, reaching a maximum during the 24 hours immediately prior to parturition. However, this increase was greatest in those sows in farrowing crates, which had previously been housed in an open environment. Heart rate was influenced by stage of gestation, posture and behaviour. Stall-housed sows had a higher basal heart rate and heart rate response to feeding than group-housed sows, perhaps indicating decreased cardiovascular fitness and an increased sympathetic nervous response to stimuli such as food. When farrowing in crates, group-housed sows had a higher heart rate response to the suckling event than stall-housed sows. This may be due to general unresponsiveness in stalled sows or to high reactivity to the suckling event in group sows caused by frustration of mother-infant interaction. When involved in agonistic interactions, the change in heart rate was greatest for sows which lost a physical interaction. Stall-housed sows had weaker bones than group-housed sows, and different muscular conformation, probably due to lack of exercise. Bone and muscle weakness may increase the susceptibility of stall-housed sows to lameness. When lying down, stall-housed sows had greater difficulty and took longer than group-housed sows. The times taken for stall sows to lie down and to stand up quickly were positively correlated with body length. For group-housed sows lying down in the open, the time taken was positively correlated with proportional locomotory muscle weight. Spatial restriction when lying resulted in the loss of muscular control. There was a positive correlation between body length and the number of piglets crushed for stallhoused sows and group-housed sows farrowing in crates. There was also a positive correlation between body length and crushing mortality for group-housed sows farrowing in pens. This indicates that sows can have problems controlling movements, even in the presence of piglets. The results presented reveal several welfare problems resulting from stall housing during pregnancy. It would appear unreasonable to confine sows during farrowing, if they have previously been housed in an open environment. However, not enough is known about the causes of piglet mortality and any decision concerning the continued use of farrowing crates must take account of the trade-off between sow welfare and piglet welfare.

Absorption of dietary proteins can be met through the uptake of free amino acids or as small peptides. A peptide transport protein, PepT1, is responsible for the absorption of intact peptides arising from digestion of dietary proteins. PepT1 is driven by a H+-coupled transport system that allows for the absorption of small peptides through the intestinal brush border membrane. Screening of a porcine intestinal cDNA library with a sheep PepT1 cDNA probe resulted in the identification of three porcine PepT1 (pPepT1) cDNAs of varying sizes and sequences. Each variant cDNA isolated was cloned into a mammalian expression vector, sequenced, and expressed in Chinese hamster ovary (CHO) cells. Peptide transport was assessed by uptake studies using the radiolabeled dipeptide [3H]-Gly-Sar. Only one of the three cDNAs encoding for a protein of 708 amino acids induced H+-dependent peptide transport activity. Through computer analysis, a putative protein structure for pPepT1 was developed. The transporter has an unusual 13 transmembrane structure with the N-terminus located extracellularly and the C-terminus located intracellularly. Seven glycosylation sites and three protein kinase C phosphorylation sites are located throughout the protein. Expression of pPepT1 activity in CHO cells had a optimal peptide uptake at 18-24 hours. The transporter showed optimal uptake at a pH of 5.5-6.0. Eighteen different unlabeled dipeptides and tripeptides were found to inhibit the uptake of [3H] -Gly-Sar in competition studies. The IC50 of 13 of the dipeptides and two tripeptides ranged between 0.015 to 0.4 mmol/L. The exceptions were Lys-Lys, Arg-Lys, and Lys-Trp-Lys, which showed IC50 values greater than 1.37 mmol/L and appear to be poor substrates for pPepT1. All three of the tetrapeptides examined showed very high IC50 values and inhibition of the uptake of Gly-Sar was too small to measure even at a 10mM concentration. Dipeptides and tripeptides appear to be substrates for the porcine intestinal peptide transporter while tetrapeptides do not appear to be transported. / Master of Science

Consumers associate meat color with quality. In some cases, especially in fresh and cured hams, the surface of a ham, whole, boneless or sectioned and formed displays a color gradient, which is unsightly and generally is considered of lower quality and must be discounted or processed different where color is less critical to the ultimate value of the resulting product. This disparity in color uniformity across fresh and cured products is sometimes known as two-toning and is most often found in the semimembranosus (SM) and associated muscles of fresh hams and is exacerbated with curing. The underlying color of fresh meat may be a function of postmortem metabolism or the underlying characteristics of those muscles involved. Therefore, the objective of this study is to determine the changes in underlying muscle type and postmortem metabolism in those muscles responsible for fresh ham color variation. Semimembranosus (SM) muscles of 15 mixed bred pigs were collected at 30 min and 1440 min postmortem, and muscle color was determined and muscles were collected and snap frozen for various energy metabolism analyses. Differences in color (L*, a* and b*) were noted across the face of the muscle by zone and time (P < 0.0001) but no differences were detected in pH and lactate, glucose, glucose-6-phosphate, and glycogen metabolisms. Glycolytic potential was also measured on a lactate basis and showed no differences across zone (P = 0.0746) but increased over time (P < 0.006). Lactate and pH were plotted and showed a linear relationship linear relationship (R2 = 0.928337) at 30 min (P < 0.0001) and at 1440 min (R2 = 0.161412; P < 0.0015). Muscle type characteristics showed no difference between zones and time. Buffering capacity showed a significant difference at pH 6 (P < 0.0359) and with time across all pH measured (P < 0.0001). These data suggest inherent differences, such as location and function, in the semimembranosus muscle may be more critical in developing fresh color than aberrations in postmortem metabolism. / Master of Science