Masters Theses

Date of Award

5-2000

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

Craig Darroch

Committee Members

Alan Matthew, Ken Stalder, Frank Masincupp

Abstract

To remain competitive in today's swine industry, producers must utilize every tool available to efficiently raise pigs to market. Nursery feeds are the most expensive feeds used by swine producers, and decreasing nursery feed costs and maintaining or improving pig growth performance in this phase of production would allow producers to increase profits.

The two experiments in this thesis research project focused on: one, the effects of using high oil corn (HOC) in a nursery phase feeding program; and two, the relative nutrient availability in HOC, damaged HOC, and commercial corn. Results from these experiments provide information that producers can use to formulate lower cost nursery diets that promote efficient growth in young pigs.

In the first study, 558 crossbred pigs (n = 293;Trial 1, n = 265 Trial 2) were weaned, segregated by sex, and weight into small, medium and heavy groups, and allotted to 12 nursery pens. Pigs received one of two dietary treatments; (1) a commercial transitional phase I diet for 7 days; a corn-based phase II diet for 14 days, and a phase III diet (NCIII) for 7 days; (2) a HOC-based phase II diet for 21 days and the NCIII diet for 7 days. Average daily gain (ADG), average daily feed intake (ADFI) and feed to gain (F/G) ratios were measured weekly during the nursery period. Pigs were transferred to a grow/finish bam on day 28, and bodyweight (BW) and ultrasound measurements were taken for back fat (BF) and loin eye area (LEA) at the 10th' and last ribs four times prior to market. ADG of nursery pigs on the three-phase diet was greater than pigs fed the HOC two-phase diet at day 21 (P = .0034) and 28 (P = .0128). ADG for heavy pigs was greater (P = .0001) than that of medium and light weight pigs, and no treatment x weight group interactions were observed (P = .2043). Pigs fed the three-phase diet had greater G/F ratios than pigs fed the HOC two-phase diet at day 21 (P = .0137) and 28 (P = .0134). LEA of pigs fed the three-phase diet was greater than that of pigs fed the HOC two-phase diet when measured on day 28 at the 10th (P = .0565) and last rib (P = .0370). There were no effects of treatment on BF. Even though pigs were fed alike in the grow/finish period, ADO of pigs fed the three-phase nursery diet was greater (P = .0106) than that of pigs fed the HOC two-phase nursery diet. Based on loin eye area and backfat measurements, throughout the grow/finish period there was a tendency (P = .0728) for pigs fed the threephase nursery diet to be leaner than pigs fed the HOC two-phase nursery diet. However, the average daily lean gain between treatments was not different throughout the experiment (P = .8611). The results suggest that removal of the transitional phase I diet and the substitution of HOC for corn in a phase II diet fed to nursery pigs did not support maximal BW and lean gains in the nursery and subsequent grow/finish periods.

In the second study, the objective of the trial was to determine the relative nutritive values of damaged high oil corn (DHOC), undamaged high oil corn (HOC), and normal yellow corn (NC). Two groups of 12 crossbred barrows, with an average initial weight of 32.1 kg, were placed in stainless steel metabolism crates in a RCBD to determine energy and protein digestibilities of HOC, DHOC, and NC. In each 10-d feeding period (5-d adaptation, 5-d collection), pigs were fed the test grain as the only source of protein and energy in the diet. Vitamins and minerals were supplied to meet NRC (1998) requirements. Damaged HOC had lower (P < .0001) 1000 kernel weights. (238.1 g; n = 5) when compared to HOC (355.4 g) and NC (272.0 g). This was related to differences in the quality of each corn type. Compared to HOC, damaged HOC had fewer intact kernels (50.8% vs 77.0%, P < .0001), more damaged whole kernels (15.9% vs 5.0%, P < .0001), more fragmented kernels (32.3% vs 17.6%, P < .0001) and more chaff (0.9% vs 0.4%, P = .0028). NC had the greatest percentage of intact kernels (87.9%), and the lowest percentages of damaged whole kernels (1.5%) and fragmented kernels (10.2%). NC and HOC had similar levels of chaff and fines. Despite differences in quality, HOC and DHOC had higher GE values (3866 kcal/kg and 4081 kcal/kg, respectively) than NC, which averaged 3562 kcal/kg. HOC had the highest level of cmde protein (9.1%), DHOC was intermediate (8.9%) and NC had the lowest cmde protein level (7.6%)(P = .0001). The coefficient for cmde protein digestibility was not different for the treatments (P = .1145). Test corn digestible cmde protein was different (P = .0001), DHOC and HOC were greater than NC, (8.1, 8.1 and 6.8 respectively). Final pig live body weights, adjusted for initial BW were not different among treatments (P = .8692), but pigs in the second replication were heavier (P = .0168) than those in the first replication. The metabolizable energy values were different for the treatments (P = .0174), 3367.1 ± 89.96, 3330.6 ± 89.68, 3002.4 ± 89.77 for DHOC, HOC and NC, respectively. The ME:DE ratios which averaged .975 were not different (P = .9952), among treatments. The results of this experiment suggest that damage to HOC did not significantly lower protein quality and availability, or have a large impact on digestible energy levels of HOC. HOC even when damaged may be used as a replacement for commercial corn in diets for growing pigs.

High oil corn in place of NC in a phase II nursery diet did not support optimum growth for nursery pigs when used in place of a transitional phase I diet in a nursery phase feeding program. However, formulation of a phase II diet containing HOC and some higher quality ingredients found in a transitional diet could lead to a diet intermediate in cost compared to a transition diet that would provide nursery pigs with the nutrients to optimize performance.

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