Using Australian Sheep Breeding Values to increase lean meat yield percentage

2010 ◽  
Vol 50 (12) ◽  
pp. 1098 ◽  
Author(s):  
G. E. Gardner ◽  
A. Williams ◽  
J. Siddell ◽  
A. J. Ball ◽  
S. Mortimer ◽  
...  

This study describes the impact of Australian Sheep Breeding Values (ASBV) for post-weaning weight (PWWT), C-site fatness (PFAT) and eye muscle depth (PEMD) on lamb carcasses within the Australian Sheep Industry CRC Information Nucleus Flock. These results are taken from the 2007 drop progeny, consisting of ~2000 lambs slaughtered at a target weight of 21.5 kg. These lambs were the progeny of sires selected to ensure genetic diversity across various production traits. As expected, the PWWT ASBV increased weight at slaughter, and hot standard carcass weight. Dressing percentage was markedly improved by increasing PEMD ASBV, thus prime lamb producers will be maintaining an animal of similar weight on farm, but delivering a markedly larger carcass at slaughter. Lean meat yield % (LMY%) was highest in the progeny of sires with low PFAT ASBV, which decreased whole carcass fatness and increased muscularity. PWWT ASBV affected carcass composition but had little impact on LMY%, as the decreased fatness was largely offset by increased bone, with relatively little change in muscle content. Lastly, PEMD ASBV had little impact on whole carcass LMY%, but did appear to cause some level of muscle redistribution to the higher value loin cuts, in turn increasing the value of the carcass lean.

Meat Science ◽  
2020 ◽  
Vol 170 ◽  
pp. 108236
Author(s):  
Matthew I. Knight ◽  
Kym L. Butler ◽  
Nick P. Linden ◽  
Viv F. Burnett ◽  
Alex J. Ball ◽  
...  

2017 ◽  
Vol 57 (2) ◽  
pp. 209 ◽  
Author(s):  
D. J. Brown ◽  
N. M. Fogarty

Breeding Merino sheep that are resistant to internal parasites alleviates the high costs associated with treatment of worm infestation and loss of production, as well as mitigating the development of anthelmintic resistance among the major worm species. Faecal worm egg count ((cube root transformation), wec) can be used in sheep as a measure of internal parasite resistance. Accurate estimates of genetic parameters for wec are required for calculation of Australian Sheep Breeding Values and inclusion of worm resistance in sheep breeding programs. This study provides updated estimates of heritability for wec and its genetic correlations with production traits. Data were analysed from a wide range of Australian and New Zealand Merino sheep in the MERINOSELECT database, which included 141 flocks with 801 flock years and up to 217 137 animals with wec recorded in at least one of four ages (W = weaning, P = post weaning, Y = yearling, H = hogget). The heritability estimates ranged from 0.16 ± 0.01 for Ywec to 0.29 ± 0.01 for Wwec, with generally high genetic correlations between the ages. Bivariate analyses estimated genetic correlations between wec at the various ages and growth, carcass quality, reproduction and wool production traits at various ages. These genetic correlations were generally small or close to zero, albeit with some significantly different from zero. The moderate heritability for wec (0.2–0.3) and its high phenotypic variation (coefficient of variation >30%) shows that relatively rapid selection response for worm resistance could be achieved. Inclusion of wec in sheep breeding programs to increase worm resistance would be expected to have little if any impact on other important production traits. These genetic parameters have been incorporated into MERINOSELECT by Sheep Genetics to provide Australian Sheep Breeding Values for wec and appropriate indices for wool and meat production. There is evidence that genotype × environment interactions may be important in some environments by reducing the accuracy of Australian Sheep Breeding Values for wec. Hence it may be prudent for breeders to implement strategies that manage the risk of any impact of genotype × environment on their breeding program.


2010 ◽  
Vol 50 (12) ◽  
pp. 1004 ◽  
Author(s):  
H. D. Daetwyler ◽  
J. M. Hickey ◽  
J. M. Henshall ◽  
S. Dominik ◽  
B. Gredler ◽  
...  

Estimated breeding values for the selection of more profitable sheep for the sheep meat and wool industries are currently based on pedigree and phenotypic records. With the advent of a medium-density DNA marker array, which genotypes ~50 000 ovine single nucleotide polymorphisms, a third source of information has become available. The aim of this paper was to determine whether this genomic information can be used to predict estimated breeding values for wool and meat traits. The effects of all single nucleotide polymorphism markers in a multi-breed sheep reference population of 7180 individuals with phenotypic records were estimated to derive prediction equations for genomic estimated breeding values (GEBV) for greasy fleece weight, fibre diameter, staple strength, breech wrinkle score, weight at ultrasound scanning, scanned eye muscle depth and scanned fat depth. Five hundred and forty industry sires with very accurate Australian sheep breeding values were used as a validation population and the accuracies of GEBV were assessed according to correlations between GEBV and Australian sheep breeding values . The accuracies of GEBV ranged from 0.15 to 0.79 for wool traits in Merino sheep and from –0.07 to 0.57 for meat traits in all breeds studied. Merino industry sires tended to have more accurate GEBV than terminal and maternal breeds because the reference population consisted mainly of Merino haplotypes. The lower accuracy for terminal and maternal breeds suggests that the density of genetic markers used was not high enough for accurate across-breed prediction of marker effects. Our results indicate that an increase in the size of the reference population will increase the accuracy of GEBV.


2003 ◽  
Vol 83 (3) ◽  
pp. 429-434 ◽  
Author(s):  
R. Bergen ◽  
D. H. Crews ◽  
Jr., S. P. Miller ◽  
J. J. McKinnon

The value of live ultrasound longissimus dorsi depth and width measurements as predictors of estimated carcass lean meat yield of steers (CARLEAN-S) and bulls (CARLEAN-B) was studied. In trial 1, equations were developed to predict estimated lean meat yield of steers (n = 116) from carcass weight (Eq. 1) or liveweight (Eq. 2), fat depth and l. dorsi area or liveweight, fat depth and l. dorsi depth × width (Eq. 3). Equation 1 was most precise (RSD = 25.6 g kg-1), followed by Eq. 2 (RSD = 27.8g kg-1) and Eq. 3 (RSD = 30.2g kg-1). Equations 2 and 3 predicted CARLEAN-S with similar accuracy (SEP = 23.8 vs. 24.9 g kg-1, respectively) and were highly correlated with each other (r = 0.89) in an independent data set (n = 118). Repeatability and accuracy of pre-slaughter l. dorsi depth and width measurements were studied in yearling bulls (trial 2; n = 191). When ultrasound measurements were expressed as a percentage of the average ultrasound measurement, repeatabilities of l. dorsi depth (SER = 6.2 to 7.8%) and width (SER = 4.2 to 6.1%) measurements were similar to fat depth and l. dorsi area measurements (SER = 17.9 and 4.5%, respectively). When ultrasound measurements were compared to the corresponding carcass measurements, l. dorsi depth (SEP = 10.3 to 13.9%) and width (SEP = 6.7 to 8.5%) measurements were as accurate as fat depth and l. dorsi area measurements (SEP = 32.9 and 8.4%, respectively). Equations were developed to predict CARLEAN-B of yearling bulls (n = 82) from liveweight, 12th rib ultrasound fat depth and either l. dorsi depth × width measurements (Eqs. 4 and 5) or two l. dorsi depth measurements (Eq. 6). All equations had similar precision (RSD = 19.4 to 19.5 g kg-1) and predicted CARLEAN-B similarly (SEP = 25.0, 24.6 and 26.1g kg-1 for Eqs. 4, 5 and 6, respectively) in an independent data set (n = 109). All equations were highly correlated (r ≥0.97) with an equation using ultrasound fat depth and l. dorsi area in the independent data set. Longissimus muscle depth and width measurements were as valuable as l. dorsi area for predicting carcass composition of yearling beef bulls in the present study. Key words: Ultrasound, beef cattle, carcass traits


2008 ◽  
Vol 51 (6) ◽  
pp. 549-559 ◽  
Author(s):  
D. Jordan ◽  
S. Žgur ◽  
G. Gorjanc ◽  
I. Štuhec

Abstract. Fattening pigs are commonly kept in intensive housing systems with slatted floor which represent a very barren environment, causing poor animal welfare. To improve such conditions a small amount of straw or hay (100 g per animal per day laid daily in a rack) was used in our study as an environmental enrichment (EE). Two replications, each including 96 fattening pigs of both sexes (3 pens of 16 females and 3 pens of 16 male castrates) from 60 kg to slaughter at average 96 kg live weight, were used to test the effect of EE and sex on behaviour, growth rate, and carcass composition. EE significantly increased the proportion of total activity during the illumination period (between 6 a. m. and 2 p. m.) on account of increased occupation with substrate (P<0.01). EE also significantly reduced time spent biting pen bars and frequency of aggressive encounters (P<0.01). The EE increased total activity in female animals during the observation period, but not in male castrates. None of the EE significantly influenced pigs‘ growth rate and lean meat percentage; however females in enriched environment grew slower and had greater lean meat percentage than the castrated males. Provision of a small amount of straw or hay to pigs in intensive housing systems can enrich barren environment in inexpensive and efficient way. Therefore such enrichment can be widely used also in large commercial pig production systems.


1993 ◽  
Vol 33 (7) ◽  
pp. 825 ◽  
Author(s):  
D Perry ◽  
AP Yeates ◽  
WA McKiernan

The association between visually assessed muscle scores on live steers and their carcasses, eye muscle area, and the yield of saleable and lean meat was determined on 156 steers of mixed breeds (mean carcass weight 282 kg, mean P8 fat depth 13 mm). The contribution of subcutaneous and intermuscular fat to differences in saleable meat yield was also investigated. There was a negative correlation between P8 fat depth and both live ( r = -0.21) and carcass muscle score (r. = -0.31); therefore, the assessors were not scoring fatter steers as having better shape. The correlation between live and carcass muscle scores was 0.79. The correlation between carcass muscle score and eye muscle area was 0.58. When live muscle score, carcass muscle score, or eye muscle area was included in regression models already containing weight and fat depth, there was a significant (P<0.001) increase in the amount of variation in saleable and lean meat yield explained by the models. At the same liveweight and fat depth, a change in live muscle score from C (moderately muscled) to B (well muscled) was accompanied by an increase of 1.7% in saleable meat and 2.2% in lean meat, when these were expressed as a percentage of carcass weight. The equivalent change in carcass muscle score in carcasses of the same weight and f a t depth was accompanied by an increase of 1.9% in saleable meat and 2.4% in lean meat. The increased weight of saleable meat was not due to an increase in the dissected fat content of the meat. Weight of subcutaneous fat decreased as muscle score increased (P<0.01). There was no significant association between the amount of intermuscular fat and either live or carcass muscle score (r. = -0.075 and -0.18, respectively).


2017 ◽  
Vol 57 (9) ◽  
pp. 1952 ◽  
Author(s):  
S. F. Walkom ◽  
D. J. Brown

Australian sheep producers have the potential to improve reproductive rates through optimising ewe body condition across the production cycle. Managing ewe body condition can become costly when supplementary feeding is required due to poor pasture growth or rainfall and by using appropriate genetics, producers can theoretically reduce the flock’s dependency on supplementary feed and improve reproductive rates. Reproductive records from the Information Nucleus Flock and Sheep Genetics Merino and maternal breed datasets were analysed to examine the influence of sire breeding values for liveweight (post-weaning, yearling and adult assessments), fat and eye muscle depths (post-weaning and yearling assessments) and number of lambs weaned on reproductive performance (fertility, litter size and number of lambs born) across a variety of production environments. To determine the impact of environmental conditions on the relationship between weight, ultrasound body composition, and reproduction traits the daughters’ adjusted reproductive performances were regressed on the sire’s breeding value across flocks, within flocks and within flock × year. Irrespective of age at assessment, sire breeding values for liveweight, fat and eye muscle depths had very little association with the reproductive performance of their daughters, on average. The regressions of reproduction on weight, and fat and eye muscle depth traits varied across flocks from unfavourable to favourable estimates. The very small overall impact of weight, and fat and eye muscle depth traits, on average suggests that using sire breeding values for number of lambs weaned, which had a large impact on reproduction, will provide the most viable method to genetically improve reproductive performance within the production system in question.


2005 ◽  
Vol 85 (1) ◽  
pp. 23-35 ◽  
Author(s):  
R. Bergen ◽  
S. P. Miller ◽  
I. B. Mandell ◽  
W. M. Robertson

Pre-slaughter ultrasound and whole side dissection data from 47 crossbred bulls were used to assess (1) the relative value of six previously published equations based on live animal measurements, (2) the value of alternative pre-slaughter measurements, and (3) the value of alternative ultrasound probes as predictors of whole side lean meat yield. Analysis of absolute bias-corrected residuals indicated that all six previously published equations predicted whole side lean meat yield with similar accuracy (P = 0.62), but analysis of absolute rank residuals indicated that an equation originally based on carcass measurements tended (P = 0.17) to rank bulls less precisely than five ultrasound-based equations. Breed composition, age, liveweight, hip width, heart girth, and round muscle depths did not contribute to new lean meat yield prediction equations (P > 0.10), but height, 12th/13th rib body wall, rump fat, and gluteus medius muscle depths and marbling score did (P < 0.10). However, examination of absolute residuals and absolute rank residuals indicated that accuracy (P = 0.55) and precision (P = 0.64) did not improve significantly compared to equations based only on height, rib fat and longissimus muscle size. Similarly, analysis of absolute residuals and absolute rank residuals indicated that fat and longissimus muscle depth measurements collected with a short probe predicted whole side lean meat yield as accurately and precisely as measurements collected with a long probe. Results indicated that (1) equations based on live measurements may provide more precise predictions of lean meat yield than equations derived from carcass measurements, (2) supplementing ultrasonic rib fat and longissimus muscle measurements with additional ultrasound measurements did not improve the accuracy or precision of lean meat yield prediction, and (3) lean meat yield of yearling bulls can be accurately predicted using fat and longissimus muscle depth measurements collected with a short probe. Key words: Ultrasound, beef bulls, carcass composition, prediction models


Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 932
Author(s):  
Weijian Li ◽  
Rongyang Li ◽  
Yinghui Wei ◽  
Xueqing Meng ◽  
Binbin Wang ◽  
...  

The Meishan pig is a traditional Chinese native breed, known for its excellent reproduction performance that is widely used in commercial pig production through two-way or three-way crossbreeding systems. However, the lean meat yield of Meishan crossbred pigs is still very low and cannot meet the market demand. To evaluate the lean meat yield of Meishan crossbred pigs, six wild-type Meishan sows were artificially inseminated by using the MSTN+/− Duroc boar semen in this experiment. Some reproductive performance-related traits of Meishan sows were recorded to ensure that semen from MSTN knockout Duroc boar did not affect offspring production, including total births, live births, sex, and litter weight. In total, 73 piglets were obtained and 63 were alive. Male to female ratio was close to 1: 1. because of factors such as disease, only 43 pigs were utilized, including 28 MSTN mutant pigs (MSTN+/−) and 15 MSTN homozygous pigs (MSTN+/+). We compared the growth performance and carcass performance of these full or half-sib populations and found that there were no differences between MSTN+/− and MSTN+/+ genotypes for live animal measures including average daily gain (ADG), body dimensions, or ultrasonic measurement of fat thickness when pigs were harvested after 120 days of feeding. Conversely, the MSTN+/− pigs had higher dressing percentage and lean meat percentage, lower level of carcass fat, larger longissimus muscle area, less percentage of skin and skeleton, thinner average backfat thickness, and lower intramuscular fat (IMF) content than MSTN+/+ pigs. In conclusion, the production of MSTN+/− mutant progeny from Meishan females resulted in improved carcass composition, providing a feasible solution to improve the lean meat yield of Chinese local fat-type pig breeds.


2009 ◽  
Vol 49 (6) ◽  
pp. 525 ◽  
Author(s):  
W. A. McKiernan ◽  
J. F. Wilkins ◽  
J. Irwin ◽  
B. Orchard ◽  
S. A. Barwick

The steer progeny of sires genetically diverse for fatness and meat yield were grown at different rates from weaning to feedlot entry and effects on growth, carcass and meat-quality traits were examined. The present paper, the second of a series, reports the effects of genetic and growth treatments on carcass traits. A total of 43 sires, within three ‘carcass class’ categories, defined as high potential for meat yield, marbling or both traits, was used. Where available, estimated breeding values for the carcass traits of retail beef yield (RBY%) and intramuscular fat (IMF%) were used in selection of the sires, which were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, to provide a range of carcass sire types across the three carcass classes. Steer progeny of Hereford dams were grown at either conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, with group means of ~400 kg. Accelerated and conventionally grown groups from successive calvings were managed to enter the feedlot at similar mean feedlot entry weights at the same time for the 100-day finish under identical conditions. Faster-backgrounded groups had greater fat levels in the carcass than did slower-backgrounded groups. Dressing percentages and fat colour were unaffected by growth treatment, whereas differences in ossification score and meat colour were explained by age at slaughter. There were significant effects of sire type for virtually all carcass traits measured in the progeny. Differences in hot standard carcass weight showed a clear advantage to European types, with variable outcomes for the Angus and Wagyu progeny. Sire selection by estimated breeding values (within the Angus breed) for yield and/or fat traits resulted in expected differences in the progeny for those traits. There were large differences in both meat yield and fatness among the types of greatest divergence in genetic potential for those traits, with the Black Wagyu and the Angus IMF clearly superior for IMF%, and the European types for RBY%. The Angus IMF progeny performed as well as that of the Black Wagyu for all fatness traits. Differences in RBY% among types were generally reflected by similar differences in eye muscle area. Results here provide guidelines for selecting sire types to target carcass traits for specific markets. The absence of interactions between growth and genetic treatments ensures that consistent responses can be expected across varying management and production systems.


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