Trent Bridge

8 | Premium Genetics for Premium Markets EBVs While we will never know the exact breeding value, for performance traits, it is possible to make good estimates based on the performance of the animal and its progeny. These are called Estimated Breeding Values (EBVs) and are therefore the best estimate of an animal’s genetic merit. EBVs are expressed as the difference between an individual animal’s genetics and a historical genetic level (i.e. group of animals) within the Wagyu BREEDPLAN genetic evaluation and are reported in the units in which the measurements are taken. ACCURACY An accuracy value is presented with every EBV and gives an indication of the amount of information that has been used in the calculation of that EBV. The higher the accuracy, the lower the likelihood of change in the animal’s EBV as more information is analysed for that animal or its relatives. • LESS THAN 50% = Low accuracy and should be considered a preliminary estimate. The EBV could change substantially as more performance information becomes available. • 50 – 74% = Medium accuracy, usually based on the animal’s own records and pedigree. • 75 – 90% = Medium-high accuracy and usually includes some progeny information. Becoming a more reliable indicator of the animal’s value as a parent. • 90% and above = High accuracy. FERTILITY AND BIRTH Scrotal Size EBV (cm) is an indicator of male fertility regarding semen quality and quantity in Western breeds of cattle. Higher (positive) EBVs indicate higher fertility. There is also a small negative correlation (desirable) with age of puberty and fertility in female progeny. The relationship between scrotal size and fertility in Wagyu is assumed, but not proven. Gestation Length EBV (days) is based on AI records. Lower (negative) GL EBVs indicate shorter gestation lengths which generally relate to lighter birth weights and easier calving. Birth Weight EBV (kg) is based on the measured birth weight of animals, adjusted for dam age. The lower the value the lighter the calf at birth and the lower the likelihood of a difficult birth. This is particularly important when selecting sires for use over heifers. GROWTH 200-Day Milk EBV (kg) is an estimate of an animal’s milking ability. For sires, this EBV is indicative of their daughter’s milking ability as it affects the 200-day weight of their calves. 200-Day Growth EBV (kg) is calculated from the weight of animals taken between 80 and 300 days of age. Values are adjusted to 200 days and for dam age. This EBV is the best single estimate of an animal’s genetic merit for growth to early ages. 400-Day Weight EBV (kg) is calculated from the weight of progeny taken between 301 and 500 days of age, adjusted to 400 days and dam age. This EBV is the best single estimate of an animal’s genetic merit for yearling weight. 600-Day Weight EBV (kg) is calculated from the weight of progeny taken between 501 and 900 days of age, adjusted to 600 days and for dam age. This EBV is the best single estimate of an animal’s genetic merit for growth beyond yearling age. CARCASE Carcase Weight EBV (kg) is based on abattoir carcase records and live weight measurements (particularly at 600-Day weight) and is an indicator of the genetic differences in carcase weight at the industry average slaughter age of 990 days. Larger positive values are more favourable. Eye Muscle Area EBV (cm2) estimates genetic differences in eye muscle area at the 12/13th rib site of a 420kg dressed carcase. A higher positive EBV indicates larger eye muscle area and therefore higher retail beef yields. Ultrasound, Aus-Meat and Japanese Digital Image Camera measurements from slaughter animals contribute to this EBV. An animal’s breeding value is its genetic merit, half of which will be passed on to its progeny.

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