Research Highlights

Applied Nutritional Studies

Growth responses to CAD-MATE vs antibiotics in nursery diets.
In a previous experiment, growth improved by 10% over the last 2 wk of a 4-wk nursery trial in pigs fed diets with 0.60 or 0.90% CAD-MATE (a source of inorganic anion salts) compared with pigs fed control diets. Antibiotics were not added to diets in the last trial and no dietary treatments were imposed during the first 2 wk of the trial.

Responses to Paylean by pigs fed diets with DDGS.
The use of dry distillers grains with solubles (DDGS) in swine diets is a common commercial practice as a method to reduce feed costs. Paylean is a swine growth promotant added to diets for 4 wk prior to market to improve feed efficiency and carcass characteristics. The current experiment was designed to determine if diets with 20% DDGS or Paylean + DDGS were economically justified for additions to SRTC finisher diets.

Nutritional value of high protein corn co-products.

Corn co-products produced by dry-milling processes for ethanol production include products with ~ 50% crude protein. Pig growth assays have been used in efforts to identify limiting nutrients in the protein co-product. Growth trials have included dietary treatments formulated to supply limiting amino acids, and to adjust mineral balance. Some improvements in growth have been observed with the dietary supplements, but efforts have not allowed recovery of pig growth to that of control pigs. An unidentified factor in the corn protein co-product limits growth by ~15% of control pigs. Poster

Short-term excesses of potassium bicarbonate for prevention of fatigue in market pigs.
The increased incidence of fatigued pigs during transport raises animal welfare and economic concerns. At the onset of fatigue, pigs exhibit metabolic acidosis. Given the intracellular distribution of potassium and the intracellular location of reactions compromised by metabolic acidosis, the current objective was to evaluate the efficacy potassium bicarbonate for prevention of acidosis in market pigs.

Nursery pig growth responses to reduced Ca:P ratios in phytase-supplemented diets.
Growth of nursery pigs (8.9 kg, n=616 pigs) over a 27 d trial was not compromised by reduction of the Ca:P ratio (0.80, 0.90 vs 1.10 Ca:P ratio) in diets supplemented with 750 FTU/kg (Phyzyme XP). Based on growth responses a reduction in the Ca:P ratio did not affect phytase activity, but skeletal responses were not measured in this experiment.

Lameness

Comparison of response criteria used to assess dietary vitamin D3 requirements in young pigs.
Recent concerns for increased mortality of young pigs attributed to vitamin D deficiencies have focused attention on response criteria used to assess vitamin D requirements. The objective of the current experiment was to determine the dose-response relationships between dietary vitamin D3 and skeleton mineral accumulation, pig growth, and serum 25-OH D3 in young growing pigs.

Supplemental vitamin D levels in gestation and lactation diets – impact on nursery pig skeletal growth.
Based on our previous results, the roles of maternal vitamin D status on fetal and neonatal skeletal tissue development need to be clarified. Observations of kyphosis in young pigs fed diets without supplemental vitamin D over relatively short trial intervals were not expected. The vitamin D status of the SRTC research herd may have contributed to the unexpected responses. The objective of this project is to characterize the effects of maternal vitamin D status on fetal and neonatal pig skeletal tissue. Poster

Vitamin D induced kyphosis: Growth, DXA skeletal traits, and spinal curvature are compromised within four weeks in pigs fed diets with no supplemental vitamin D.
Recent necropsy reports from commercial operations have implicated vitamin D (D) deficiency as a cause for mortalities in young pigs. Vitamin D deficiencies are not typical in young pigs. Evidence of D deficiency that induced kyphosis, an abnormal spine curvature, in young pigs fed D-limited diets for 9 or 13 wk was reported last year. Poster

Efficacy of vitamin D supplements in day-old pigs.
Compared with non-treated controls (Ctl), an oral dose of vitamin D (+D, 40,000 IU D3) administered to pigs at birth increased serum 25-OH D3 at weaning (Ctl vs +D pigs, 9.5 vs 29.8 + 2.3 ng/L). Poster

Recovery of bone mineralization and strength after a marginal dietary calcium deficiency in growing pigs.
Compensatory response following a period of nutrient deficiency improves efficiency of nutrient use. After a period of Ca and P depletion young pigs failed to compensate for a reduction in bone mineral content (BMC), but femur strength was restored (Aiyangar et al., 2010. Medical Engineering & Physics 32:1116-1123). A brief period of P deficiency may reduce animal growth, but a brief period of Ca deficiency is unlikely to reduce growth. Both Ca and P are required for bone mineral deposition. Thus, a deficiency of Ca may limit bone accretion, but not affect growth. Poster

Expression of kyphosis in young pigs is altered by carryover effects of sow vitamin D status.
Kyphosis, or ‘hump-back pigs’, is an idiopathic disease that may affect ~30% of pigs in herds during an acute outbreak. The UW Swine Center herd had a flare-up and subsidence (~20% incidence) of kyphosis over 4 mo in 2008. The incidence was consistent with unintentional omission of vitamin D (D) from all diets. Poster

Role of FGF23 in a novel pathway for vitamin D mediated phosphate homeostasis.
The interrelationships among Ca, parathyroid hormone (PTH), and conversion of 25-OH vitamin D3 to the active hormone, 1α,25-(OH)2D3 have been used to describe Ca homeostasis. Relatively little research has focused on these interrelationships and P homeostasis. In the past decade, discovery of a previously unrecognized hormone, fibroblast growth factor 23 (FGF23), has revealed a novel pathway directly involved in P homeostasis. Recovery of skeletal growth and mineralization from dietary calcium deficiency in young growing pigs. Young (9.2 kg) pigs were subjected to a 4-wk depletion (70 vs 150% of Ca requirements) each with a 6 wk repletion (70/70, 70/150, 150/70, 150/150) period to assess skeletal recovery following periods of deficiency. Femurs collected at the end of the trial were used to compare predictions of strength properties based on structural, geometric and physical parameters computed using data from computed tomography (CT) scans with mechanical properties derived from four-point bending tests. Poster

Dietary additions of flaxseed compromised skeletal growth in young pigs.
Flaxseed provide a source of n-3 fatty acids with potential solutions to stability issues identified with most supplemental sources of unsaturated fats. In previous studies, neonatal pigs fed diets enriched with n-3 fats had compromised skeletal integrity compared with pigs fed diets with n-6 fat supplements. In this experiment nursery pigs (8.4 kg) were fed diets with either 0, 7.5, or 15% flaxseed additions. Poster

Efficiency of Dietary Calcium Use for Skeletal Growth and Mineralization in Young Pigs Fed Diets with Various Phosphorus Concentrations.
Efficiency of nutrient use (nutrient retained/consumed) is typically higher in animals fed diets with marginal deficiencies compared with animals allowed adequate intake of the nutrient. However, in an earlier experiment, Ca efficiency was lower in pigs fed diets with a marginal Ca deficiency compared with Ca efficiency of pigs fed diets with excess Ca. The previous study (J Bone Miner Res 20:S193) was designed to assess recovery of skeletal growth in young pigs following a period of deficit growth induced by a Ca deficiency. Dietary P concentrations may have limited the efficiency of Ca use.

DXA scans of pig feet accurately predict bone ash content.
Dual-energy X-ray absorptiometry (DXA) offers a rapid method to predict bone ash content of humans, animals, and tissues. Earlier work in our laboratory demonstrated that the GE Lunar Prodigy instrument (software version 10.10.038), in selected scan modes, accurately predicted the bone ash content of pigs from 1 to 60 kg. The current experiment was designed to assess the accuracy of DXA scans of pig feet as a rapid screening method to evaluate qualitative responses by pigs to nutrient treatments affecting mineral status. Poster

Reproduction

Dose-responses to dietary additions of anionic mineral salts fed to gestating sows.
An increase in unexplained sow mortality during the prepartum and early postpartum periods has led to purported claims of hypocalcemic disorders in sows. In commercial dairy operations, anionic salts are added to late gestation and early lactation diets to reduce hypocalcemic disorders. In the current experiment sows were fed diets with 6 levels (0 to 2.5%) of anionic salts to assess acid-base status and renal compensation in response to acid loads. Poster

Behavior responses of gestating sows to housing in a “Flex-crate”.
A prototype “Flex-crate” was designed to allow rapid adjustments in the mid-section crate width for gestating sows. Continuous video recordings were collected over the entire gestation period for 12 sows to determine the functionality and practicality of adjustments in the Flex-crate as sow dimensions change during gestation. Video recordings are being transcribed to assess behavior responses by sows.

Noni Porcine Boost™ for gestating & lactating sows: Effect on immunity and production.
Noni Porcine Boost™ is a puree of Noni fruit (NFE).  As a food supplement for humans NFE has a variety of purported health benefits ranging from antidepressant therapy to improvements in digestion. Improved immunological activity against E. coli was observed in calves fed NFE (Schaefer et al., J. Vet. Intern. Med.). Only a few studies have reported responses of pigs fed NFE. Swine are most susceptible to health challenges during the early neonatal and post-weaning periods. This study was designed to evaluate responses of 30 sows fed NFE during late gestation and lactation periods and responses of their offspring during the early neonatal and nursery periods.

Biomedical

Expansion of the porcine model for Ca oxalate urolithiasis – 42 d Trial.
Development of a swine model for calcium oxalate stone disease offers a significant contribution to kidney stone research. Calcium oxalate is the predominate form of renal stones found in humans and companion animals. In an earlier study, calcium oxalate stones were detected in one sow following 21 d consumption of a diet supplemented with 10% L-hydroxyproline (HP).
The current trial was designed to further evaluate the incidence of stones in sows fed HP diets and the maintenance of stones following withdrawal of HP.

Hydroxyproline and gelatin diets induce hyperoxaluria and formation of renal stones in sows.
Development of a swine model for calcium oxalate stone disease offers a significant contribution to kidney stone research. Calcium oxalate is the predominate form of renal stones in humans and companion animals. In an earlier study, gestating sows fed diets with either 10% added hydroxyproline or the equivalent amount of hydroxyproline from gelatin increased urinary oxalate and glycolate excretion over a 21-d trial.

Hydroxyproline and gelatin diets induce long-term hyperoxaluria in sows.
Development of a swine model for calcium oxalate stone disease offers a significant contribution to kidney stone research. Calcium oxalate is the predominate form of renal stones in humans and companion animals. In an earlier study, gestating sows fed diets with 10% added hydroxyproline increased urinary oxalate and glycolate excretion.