Effect of Technician, Machine, and Animal Body Composition on Accuracy of Ultrasonic Measures of Backfat and Loin Muscle Area in Swine

Records (n = 11,305) from the 1998 to 2003 National Swine Improvement Federation (NSIF) ultrasound certification programs were used to determine the effect of technician, machine (A-mode and B-mode: Aloka 500, Classic Scanner 200), and level of animal fat depth and loin muscle area on the accuracy of tenth rib off-midline backfat (BF10) and loin muscle area (LMA) measured on live pigs

Growth Comparison and Fecal Mineral Excretion of Inorganic and Organic Trace Mineral Supplementation in Swine

Fecal Analysis, off-test weights, and ultrasonic measurements were used to determine the response of BioplexTM trace minerals on the fecal mineral excretion (copper Cu, iron Fe, and zinc Zn) and growth and performance traits measured on live pigs (n=528). The use of BioplexTM mineral supplementation on phase fed growfinish pigs could potentially decrease the amount of heavy metal and nutrient excretion without impacting the overall performance of the animal. These organic mineral supplements can ultimately be fed to finishing swine without having a significant effect on percent lean (live or carcass), loin muscle area (LMA), backfat (BF10), average daily gain (ADG), or feed efficiency (FE). The use of BioplexTM trace minerals has the potential to reduce the environmental impact of swine production without any loss of production efficiency to the producer. Future work in the use of BioplexTM trace minerals and other mechanisms to reduce the environmental impact of swine production is warranted

The Effects of Long Term Selection for Reduced Backfat and Increased Loin Muscle Area on Meat and Eating Quality Traits in Duroc Swine

A study was conducted to evaluate differences in performance, carcass composition, and eating quality characteristics of pigs sired by purebred Duroc boars currently available and pigs sired by purebred Duroc boars from the mid 1980’s. Two lines were developed by splitting and randomly allocating littermate and ½ sib pairs of females to matings by current (CTP) or old (OTP) time period boars. Subsequent boar, barrow, and gilt progeny from two replications were weighed on test at a group mean live weight of 140 lbs. Off-test ultrasonic LMA, BF10, and IMF measurements were collected on 789 pigs at a mean live weight of 240 lb. Records on pigs sired by CTP boars, from both replications (n=556), represented 23 sires while pigs sired by OTP boars (n=231) consisted of 15 sire groups. All available barrows and randomly selected gilts (n=277) were sent to a commercial abattoir and measurements of tenth-rib backfat (CBF10), last rib backfat (CLRBF), last lumbar backfat (CLLBF), and loin muscle area (CLMA) were collected. Chemical intramuscular fat percentage was determined by lab analysis of a loin sample from the 10th rib face of the longissimus muscle. Additional meat and eating quality traits measured were: Minolta reflectance and Hunter L (24 and 48 h); pH (24 h and 7 d); water holding capacity; subjective visual scores for color, marbling, and firmness (48 h); Instron tenderness, cooking loss, and trained sensory panel evaluations (7 d). Six serial ultrasonic measurements of 10th rib loin muscle area (LMA), off-midline backfat (BF10), and intramuscular fat percentage (IMF) from the first replication were collected every two weeks and used to assess deposition rate and growth pattern differences. There was no significant difference in average daily gain of pigs sired by boars from the two time periods. Pigs sired by CTP boars had larger (P \u3c 0.05) LMA measurements and less BF10, while pigs sired by OTP had significantly more IMF. Carcass evaluation revealed larger CLMA measurements, and significantly less CBF10, CLRBF, and CLLBF measurements for pigs sired by CTP boars. Pigs sired by OTP boars had a higher intramuscular fat percentage, lower Instron tenderness values, and higher subjective marbling and color scores than pigs sired by CTP boars (P \u3c 0.05). There were no significant differences between time periods for Minolta reflectance, Hunter L (24 and 48 h), water holding capacity, pH (24 h and 7 d), and subjective firmness scores. Trained sensory evaluations revealed higher (P \u3c 0.05) flavor scores and lower off-flavor scores for OTP sired pigs; however, no significant differences in tenderness score, juiciness score, chewiness score, and cooking loss were found between lines. Progeny of OTP boars began the test period at heavier weights and begin to decrease in daily body weight gain toward the conclusion of the test period, finishing with no advantage in body weight when compared to progeny of CTP boars. The analysis of serial backfat measurements revealed a linear pattern of backfat deposition between 150 and 270 lbs. Pigs sired by OTP boars deposited more backfat (