Relationship between body measurements, metabolic hormones, metabolites and residual feed intake in performancetested pedigree beef bulls

Kelly, A. K.; McGee, M.; Crews, D. H.; Lynch, C.O.; Wylie, A.R.G.; Evans, R.D.; Kenny, David A.

doi:10.1016/j.livsci.2010.05.018

Cited by 40 publications

(37 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The current study has shown that for growing beef bulls, weight and growth accounted for a substantial proportion (0.79) of the variation in RFI and that high RFI bulls had a 14% greater DMI than low RFI bulls for the same level of production. This result is in agreement with the findings of Schenkel et al (2004), Lancaster et al (2009) and Kelly et al (2011) who found that weight and growth accounted for between 0.62 and 0.82 of the variation in RFI in growing bulls on a high concentrate diet. Previous studies with bulls have shown that high RFI animals have a greater content of subcutaneous body fat than those of low RFI (Lancaster et al, 2009;Smith et al, 2010;Kelly et al, 2011).…”

Section: Discussionsupporting

confidence: 93%

“…This result is in agreement with the findings of Schenkel et al (2004), Lancaster et al (2009) and Kelly et al (2011) who found that weight and growth accounted for between 0.62 and 0.82 of the variation in RFI in growing bulls on a high concentrate diet. Previous studies with bulls have shown that high RFI animals have a greater content of subcutaneous body fat than those of low RFI (Lancaster et al, 2009;Smith et al, 2010;Kelly et al, 2011). Similarly, Crowley et al (2011) found that RFI had a positive phenotypic (r = 0.26; P < 0.05) and genetic (r = 0.39) correlation with fat depth in bulls.…”

Section: Discussionsupporting

confidence: 93%

“…Animal performance and feed efficiency Overall ADG, initial BW and DMI of the bulls used in the current study are within the ranges observed by Schenkel et al (2004), Lancaster et al (2009) and Kelly et al (2011) for growing beef bulls offered an energy dense, high concentrate diet. The current study has shown that for growing beef bulls, weight and growth accounted for a substantial proportion (0.79) of the variation in RFI and that high RFI bulls had a 14% greater DMI than low RFI bulls for the same level of production.…”

Section: Discussionsupporting

confidence: 68%

“…Results in the literature on the effect of RFI on LD depth are inconsistent, in that Crowley et al (2010) found that the phenotypic correlation between LD depth in bulls and RFI was negative, whereas Kelly et al (2011) found that final LD depth was lower in low compared with high RFI bulls. In the current study, ultrasonic LD depth was not affected by RFI.…”

Section: Discussionmentioning

confidence: 97%

“…These findings are in agreement with those of Montanholi et al (2009) who found no differences in mid-trial backfat for crossbred bulls of high, medium and low RFI. The conflicting reports on the effect of phenotypic RFI on subcutaneous fat depth, may be due to variation in fat deposition in different breeds and differences in the site for ultrasonic measurement selected by operators (Kelly et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

See 4 more Smart Citations

Visceral organ weights, digestion and carcass characteristics of beef bulls differing in residual feed intake offered a high concentrate diet

Fitzsimons

Kenny

McGee

2014

Animal

Self Cite

View full text Add to dashboard Cite

This study examined the relationship of residual feed intake (RFI) with digestion, body composition, carcass traits and visceral organ weights in beef bulls offered a high concentrate diet. Individual dry matter (DM) intake (DMI) and growth were measured in a total of 67 Simmental bulls (mean initial BW 431 kg (s.d. = 63.7)) over 3 years. Bulls were offered concentrates (860 g/kg rolled barley, 60 g/kg soya bean meal, 60 g/kg molasses and 20 g/kg minerals per vitamins) ad libitum plus 0.8 kg grass silage DM daily for 105 days pre-slaughter. Ultrasonic muscle and fat depth, body condition score (BCS), muscularity score, skeletal measurements, blood metabolites, rumen fermentation and total tract digestibility (indigestible marker) were determined. After slaughter, carcasses and perinephric and retroperitoneal fat were weighed, carcasses were graded for conformation and fat score and weight of non-carcass organs, liver, heart, kidneys, lungs, gall bladder, spleen, reticulo-rumen full and empty and intestines full, were determined. The residuals of the regression of DMI on average daily gain (ADG), mid-test metabolic BW (BW 0.75 ) and the fixed effect of year, using all animals, were used to compute individual RFI coefficients. Animals were ranked on RFI and assigned to high (inefficient), medium or low groupings. Overall mean ADG and daily DMI were 1.6 kg (s.d. = 0.36) and 9.4 kg (s.d. = 1.16), respectively. High RFI bulls consumed 7 and 14% more DM than medium and low RFI bulls, respectively (P < 0.001). No differences between high and low RFI bulls were detected (P > 0.05) for ADG, BW, BCS, skeletal measurements, muscularity scores, ultrasonic measurements, carcass weight, perinephric and retroperitoneal fat weight, kill-out proportion and carcass conformation and fat score. However, regression analysis indicated that a 1 kg DM/day increase in RFI was associated with a decrease in kill-out proportion of 20 g/kg (P < 0.05) and a decrease in carcass conformation of 0.74 units (P < 0.05). Weight of non-carcass organs did not differ (P > 0.05) between RFI groups except for the empty weight of reticulo-rumen, which was 8% lighter (P = 0.05) in low RFI compared with high RFI bulls. Regression analysis indicated that a 1 kg DM/day increase in RFI was associated with a 1 kg increase in reticulo-rumen empty weight (P < 0.05). Of the visceral organs measured, the reticulo-rumen may be a biologically significant contributory factor to variation in RFI in beef bulls finished on a high concentrate diet.Keywords: beef cattle, body composition, carcass traits, residual feed intake, visceral organs ImplicationsThis study confirms that residual feed intake (RFI) is a measure of feed efficiency that is independent of BW and level of production in beef cattle. Additionally, carcasses of low RFI bulls were associated with an improvement in economically important traits such as kill-out proportion, carcass conformation score and predicted meat proportion. Weight of the reticulorumen, may be a biologically significant contributory ...

show abstract