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Kerala Veterinary and Animal Sciences University, Wayanad

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Subject: Livestock Product Technology × Author: JISHNU P. × End date: 2023 × Start date: 2020 × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    ULTRASONIC MEASUREMENT OF BACK FAT THICKNESS AND LOIN EYE AREA IN CROSSBRED PIGS AND THEIR CORRELATION WITH MEAT YIELD AND FATTY ACID PROFILE
    (COLLEGE OF VETERINARY & ANIMAL SCIENCES MANNUTHY, THRISSUR, KERALA VETERINARY AND ANIMAL SCIENCES UNIVERSITY, 2022-03-08) JISHNU P.; Dr. V. N. Vasudevan
    The present study was conducted to determine backfat thickness and loin eye area of live pigs at different body locations using real-time ultrasonography and to find their correlation with direct carcass measurements of backfat thickness and loin eye area made in pig carcasses after slaughter and with attributes related to meat yield. Fatty acid profile of different fat depots of pig carcasses was also determined. The study was carried out in 102 crossbred pigs of different slaughter weight at Meat Technology Unit, Mannuthy. The pigs were divided into three weight groups viz. group I - less than 80 kg, group II – 81 to 120 kg and group III- 121 kg above. Body length, heart girth and flank girth measurements differed significantly (p<0.05) between the weight groups. At the last and 10th rib positions, thickness of outer and middle fat layers measured using ultrasound showed significant (p<0.05) difference between the three weight groups. Ruler measurements of backfat thickness and loin eye area in carcasses of group III pigs differed significantly (p<0.05) from the other two groups. No significant difference was observed for yield of ham, ham meat yield, yield of Boston butt and Boston butt meat yield. Carcass length and hot carcass weight differed significantly (p<0.05) between the three weight groups. There were no significant differences between three weight groups for total meat yield and per cent separable fat. Intramuscular fat content was significantly (p<0.05) lower in group I than the other two heavier weight groups. Mean ultrasound measurements of back fat thickness and loin eye area at different position made in live pigs were significantly lower than the corresponding ruler measurements made in carcasses.Body length, heart girth and flank girth were significantly (p<0.01) correlated with body weight of animals in all the weight groups. Heart girth showed significantcorrelation with thickness of carcass total backfat (CBFT) at 10th rib and last rib positions of all the groups. Heart girth showed significant (p<0.01) correlation with carcass weight and total meat yield in group I pigs. Heart girth showed significant (p<0.01) correlation with carcass weight, dressing percent, total meat yield and separable fat in group II pigs. Ultrasonically measured total backfat thickness (USBFT)at 10th rib showed higher correlation with CBFT than USBFT at last rib for group I and group II. Angle was significantly (p<0.05) correlated with thickness of outer layer of backfat (CBFO) and CBFT in group I pigs while angle showed significant (p<0.01) correlation with thickness of middle layer of backfat (CBFM) at 10th rib and last rib positions of group II pigs.Multiple linear regression analysis was carried out to predict some economically important carcass parameters using live animal physical and ultrasound measurements. Adjusted coefficients of multiple determination (adjusted R2) were lower when equations were developed for predicting economically important traits like dressing per cent, meat yield, separable fat and intramuscular fat using heart girth, angle and ultrasonic measurements. However, equations for predicting CBFT at 10th rib and last rib using heart girth alone or in combination with USBFT values had higher adjusted R2 values. The extent of saturation of fatty acids increased from outer layers of backfat to inner fat depots of the body.The results of the present study indicate that significant differences can exist between live animal ultrasonic and carcass measurements of different carcass parameters. A combination of live animal physical and ultrasonic measurements can be used as important predictors for some of the economically important carcass traits.