Genetics of slaughter precocity, carcass weight, and carcass weight gain in Chianina, Marchigiana, and Romagnola young bulls under protected geographical indication1

Abstract

The aim of this study was to estimate the heritability and genetic correlation of age at slaughter (AS), as an indicator of slaughter precocity, carcass weight (CW), and CW gain (CWG = CW × AS(-1)) obtained from young bulls of 3 Italian autochthonous beef cattle breeds [i.e., Chianina (CHI), Marchigiana (MAR), and Romagnola (ROM)]. In addition, the study aimed at evaluating the effect of corrected or uncorrected CW for AS, and analyzing the relationship between adjusted or unadjusted CW with CWG in term of changes in rank correlation in groups of sires with high accuracy. Data were obtained from the Consortium of protected geographical indication (PGI) "Vitellone Bianco dell'Appennino Centrale" (i.e., white young bull of Central Apennines), approved by the European Union. After editing, 20,872 complete records were retained for subsequent Bayesian analysis. Univariate animal model produced h(2) estimates of medium value for AS (i.e., from 0.28 for CHI to 0.39 for the ROM breed). The CW presented h(2) estimates less than AS, ranging from 0.13 for CHI to 0.24 for ROM bulls. The adjustment of CW by AS (CWU-AS) increased the h(2) values for CW in all breeds (i.e., from 0.20 to 0.29). Point estimate of genetic correlations between AS and CW obtained by a bivariate analysis were moderate to low, and negative in all breeds (from -0.08 to -0.29). Rerankings of sire for univariate CW (CWU) analysis and CWU-AS were more noticeable for CHI and ROM (rank correlation of 0.875 and 0.897, respectively) than for the MAR breed (rank correlation of 0.967). Comparing bivariate EBV for CW with EBV for CWU or CWU-AS increased rank correlation to 0.937 for ROM, but for CHI it remained lower (i.e., 0.861), indicating a possible large reranking of sires by correcting CW for AS in this breed. Daily CWG presented h(2) estimates greater than CW and similar or greater than AS. It appears to be a good indicator of instant growth rate capacity of the animal but lacking information on the endpoint of fattening in terms of age and weight. Field slaughter data for the CHI, MAR, and ROM breeds under the PGI labeling indicate that AS is not a mere environmental factor to be corrected for but trait subjected to genetic control. Because of its economic relevance in fattening, age at slaughter, as an indicator of slaughter precocity, could become a trait requiring careful consideration for selection of beef breeds.

Relationships of a Detailed Mineral Profile of Meat with Animal Performance and Beef Quality

“…The majority of the young bulls and heifers are reared on smallmedium farms, and both the cow-calf and fattening phases have one of the highest gross margins per cow in the EU [24]. The performance traits measured in this study are very similar to those reported in a previous large survey of more than 20,000 animals [14], which also found that Chianina cattle have a greater carcass weight than the Romagnola (430 kg vs. 367 kg, respectively),…”

“…Slaughter date is decided by the farmer for each animal individually according to local market requirements, i.e. at carcass fatness scores of about 2.0 for young bulls and 2.5 for young heifers [14] on the European SEUROP carcass classification system [15].…”

“…Among the animal performance traits, it was positively correlated only with age at slaughter at the level of individual animals within farm/date groups. It is worth pointing out that age at slaughter also has a genetic aspect as it reflects the earliness or lateness of maturation of the animals [14], and is negatively correlated with carcass weight, carcass gain and fat deposition, which could reflect greater mineral deposition in the meat of animals that require a longer fattening period to reach the level of maturation required by the market.…”

A Survey on Feedlot Performance of Purebred and Crossbred European Young Bulls and Heifers Managed Under Intensive Conditions in Veneto, Northeast Italy

“…Also the BW at slaughter showed a progressive increase during the last decades, probably due to: i) the increase of average BW at purchase; ii) the need to dilute the negative differential between purchase and sale prices per kg in a higher BW gain; iii) the genetic improvement of mature size as an indirect response to selec-tion for increased growth rate (Perry and Arthur, 2000); iv) the delayed tendency for fat deposition caused by increased muscular development potential (Renand et al, 1996;Sbarra et al, 2013). The only partial exception to this regard concerned LI young bulls, that evidenced only a slight increase of final BW in the last 30 years.…”

Relationships of a Detailed Mineral Profile of Meat with Animal Performance and Beef Quality

“…Silages are prohibited during the last two months of fattening. Slaughter date is decided by the farmer for each animal individually according to local market requirements, i.e., at carcass fatness scores of about 2.0 for young bulls and 2.5 for young heifers [14] on the European SEUROP carcass classification system [15].…”