*2.2. Selection of Animals and Meat Samples*

Three groups of animals were the source for the meat samples in the present study: *(i)* Israeli Holstein male calves (N = 205), reared and fattened, from weaning to slaughter, in two farms located in the northern part of Israel: Farm 1 (F1; N = 62) and Farm 2 (F2; N = 143), at the age of ~12 months. *(ii)* Farm 3 (F3; N = 169), Australian male calves, imported to Israel at the age of 8–12 weeks. Their genetic background included a mix of *Bos indicus* (mostly Brahman) and *Bos taurus*. The three farms were located in each other's vicinity. The three farms used similar rearing protocols and dietary design, provided by Bakar Tnuva. The diet was composed of ground corn (38.97%), gluten feed (8.13%), cotton seeds (pima; 3.75%), DDG (7.71%), Ca—salt (1.22%), Vit mix (0.17%), Whey (30.87%), wheat hay (4.38%), and wheat straw (4.82%). At the age of 12 months, one day prior to slaughter, the animals were transferred to Bakar Tnuva abattoir, and slaughtered on the following morning under similar conditions, as a single group. The carcasses were then trimmed and gradually chilled, initially at 18 ◦C, for several hours (±8 h), to avoid cold shortening, then hanged overnight, at 1 ◦C, in the chilling room. The individual records of live body weight (BW) at slaughter and carcass weight were provided in real time.

On the following morning, the carcasses were cut between the 12 and 13th ribs, and boned out from the rib to the lumbar sacral junction. The *longissimus dorsi et lumborum (LL)* muscle (the posterior side of the *longissimus dorsi* muscle) was taken off the left halfcarcass of each animal, and the subcutaneous fat and epimysium were removed from the muscle. The muscles were delivered to the laboratory in isothermal containers at refrigerated temperature, within 1.5 h, for phenotyping of the meat quality characteristics, as described below.

#### *2.3. Muscle Preparation*

In the laboratory, the *LL* muscles were immediately cut into 280–300 g steaks. Two of the steaks were sealed in plastic bags and kept in a dry aging refrigerator (at 0–2 ◦C) for 48 h, then kept at −20 ◦C for cooking loss (CKL) and Warner-Bratzler Shear Force (WBSF) analysis. A third steak was used for the determination of the pH and color, followed by analyses of chemical composition, sarcomere length (SL), water holding capacity (WHC), total collagen content and fatty acid (FA) profile.
