Effects of sire line, sire, and sex on plasma urea nitrogen, body weight, and backfat thickness in offspring of Duroc and Landrace boars

• Published in: Journal of animal science Vol. 84; no. 6; pp. 1323 - 1330
• Main Authors: Klindt, J, Thallman, R.M, Wise, T
• Format: Journal Article
• Language: English
• Published: Savoy, IL American Society of Animal Science 01-06-2006; Am Soc Animal Sci
• Subjects: Adipose Tissue - anatomy & histology; American Landrace; Animal Feed; Animal productions; Animals; artificial selection; backfat; barrows; Biological and medical sciences; blood chemistry; Blood Urea Nitrogen; boars; Body Composition - genetics; body weight; Body Weight - genetics; Duroc; Female; Food industries; Fundamental and applied biological sciences. Psychology; gender differences; genetic variation; genotype; gilts; liveweight gain; Male; Meat and meat product industries; Sex Characteristics; sire line; sires; Swine - genetics; Swine - growth & development; Terrestrial animal productions; thickness; urea; urea nitrogen; Vertebrates; Farming animal; Body weight; Sex; Meat product; Nitrogen; genetic influence; Sire; Pig; Thickness; Urea; plasma urea nitrogen; Vertebrata; Meat animals; Mammalia; Backfat; Ureas; growth; Artiodactyla; Ungulata
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/2006.8461323x

In pork production, the efficiency of dietary protein (AA) use is low, resulting in urinary excretion of large quantities of nitrogen as urea. Use of AA and formation of urea are under enzymatic regulation, suggesting genetic regulation. The current study examined the effects of sire line, sire, and sex on growth characteristics and plasma urea nitrogen (PUN) concentrations in the offspring of 11 Duroc sires and 11 Landrace sires bred to Yorkshire-Landrace dams. Plasma samples were obtained at approximately 107 (age class = 107 d), 128 (age class = 128 d), and 149 (age class = 149 d) d of age from 511 boars, gilts, and barrows group-penned and fed standard finishing diets. Body weight and backfat (BF, mean of 3 measurements) were recorded at the time of blood sample collection. Sex, age class, and their interaction influenced (P < 0.01) BW, BF, and PUN. Predicted traits (i.e., ADG, BW at 21 wk, average daily change in BF, BF at 21 wk, and the mean of 3 PUN measures) were generated. Means (±SD) were: ADG, 888 ± 204 g; BW at 21 wk, 94.2 ± 12.5 kg; average daily change in BF, 0.083 ± 0.052 mm; BF at 21 wk, 13.8 ± 3.0 mm; and the mean of 3 PUN measures, 16.2 ± 4.4 mg/dL. Predicted weight traits were influenced (P < 0.05) by sire line, and sex influenced (P < 0.01) all predicted traits. Heritability estimates for PUN at 107, 128, and 149 d of age were 0.35 ± 0.15, 0.21 ± 0.13, and 0.16 ± 0.12, respectively. Phenotypic correlations of PUN with growth and fat traits were low. Genetic correlations of PUN measured at 107 d with growth and fat traits were low. However, genetic correlations of PUN measured at 128 or 149 d with growth and fat traits ranged from 0.81 to 0.95. Determination of PUN, as herein, may be of sufficient precision to allow its use in a selection protocol. Selection of pigs with superior growth performance and low PUN may result in a greater efficiency of dietary nitrogen use and a reduced negative environmental impact.