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Title:Effect of sire line and rate of gain on pork quality
Author(s):Schunke, Emily Danielle
Advisor(s):Dilger, Anna C
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):sire line
rate of gain
growth performance
pork quality
Abstract:Terminal sire selection is a critical factor in modern day swine production as it has the ability to influence characteristics that affect the financial stability of the producer and packer while concomitantly influencing the eating experience of the consumer. Pietrain pigs are often utilized in swine production as they increase feed efficiency and improve both carcass and lean yields whereas, Duroc pigs are known for fast growth and improved overall meat quality. Three experiments were conducted to evaluate the effects of Duroc and Pietrain sire lines on growth performance, carcass cutability, and early and aged pork quality. For these three experiments, the MIXED procedure of SAS was used to evaluate the fixed effects of sire line, sex, and their interactions on pork quality and considered significant at P<0.05. In the first study, an American purebred (AP) Pietrain terminal sire line (n=135) was selected for feed efficiency and lean tissue accretion while a European crossbred, 25% Pietrain, (EC) terminal sire line (n=114) was chosen for lean tissue accretion and carcass merit. As expected, EC sired pigs had an increased (P=0.03) standardized fat free lean (FFL) by 1.63% units. American Pietrain sired pigs had darker loins and chops as early ventral visual color was increased (0.46 units, P<0.001), early ventral L* was decreased (0.89 units, P=0.05), early chop visual color was increased (0.14, P=0.03), and early chop L* was decreased (1.18, P=0.03). Overall, EC sired pigs were leaner, while AP sired pigs had darker (early) loins and chops. In a second experiment, a Duroc terminal sire line (n=160), selected for premium meat quality based programs (MQ), was compared to a Duroc terminal sire line (n=144) that was selected for competitive growth and performance (GP). Overall (d0-98), GP sired pigs had increased G:F (0.01 kg/d, P=0.03), while MQ sired pigs had darker, heavier marbled loins as early ventral L* was decreased (1.67, P=0.01) and early ventral visual marbling was increased (0.28, P<0.01). Aged ventral visual marbling was increased (0.28, P<0.001) in MQ sired pigs. Belly thickness and flop were increased (P<0.01) by 0.19 cm and 3.5 cm, respectively in MQ sired pigs. Ultimately, GP sired pigs had increased G:F, but MQ sired pigs had improved pork quality. In a third experiment, pigs were sourced from 2 different sire lines of Duroc ancestry. Red (n=160) and Green (n=160) represented either a P26 Duroc sire line or a competitor Duroc sire line. Overall, Green sired pigs had increased average daily gain (ADG; 0.07, kg/d, P<0.001), while Red sired pigs had increased FFL (1.31%, P<0.01). Loin marbling scores were higher (P≤ 0.01) in both the aged ventral (0.48) and chop (0.36) of Green sired pigs. Additionally, Green sired pigs had thicker and firmer bellies as indicated by increased (P<0.001) belly thickness (3.97 vs. 3.59) and belly flop (19.64 vs. 15.63). Ultimately, Red sired pigs were leaner leading to greater carcass merit, but Green sired pigs had increased ADG and improved pork quality characteristics. Lastly, pork hot carcass weights (HCW) have increased from 82 to 96.5 kg over the last 25 years. As carcasses become heavier, chops become more tender. One possible explanation for this increase in tenderness is increased ADG or growth rates in pigs that reach heavier weights. Therefore, 634 pigs (Duroc or Pietrain sire ancestry) were sourced from 4 separate groups which were raised over two and a half years. Pigs were raised under the same conditions and divided into three groups based on ADG (kg/d) from 12-26wk of age; slow (<0.96kg/d, n=96), intermediate (0.96-1.16kg/d, n=452), and fast (≥1.17kg/d, n=86). Overall ADG was increased (P<0.001) in fast growing pigs by 0.15 kg/d. Aged ventral visual color was increased (P=0.03) in fast and intermediate growing pigs by 0.23 units. Intermediate growing pigs had firmer loins (P=0.04) by 0.07 units. Ventral a* increased as growth rate increased (P=0.04) indicating fast growing pigs had the reddest loins (9.77 vs. 9.26 vs. 8.99). Instrumental tenderness did not differ (P=0.51) between growth rate groups. While faster growth rates improved aged ventral visual color, instrumental tenderness did not differ between groups.
Issue Date:2020-04-23
Type:Thesis
URI:http://hdl.handle.net/2142/107901
Rights Information:Copyright 2020 Emily Schunke
Date Available in IDEALS:2020-08-26
Date Deposited:2020-05


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