Calving ease breeding values are an important consideration for breeders as calving difficulties and longer gestation lengths can effect the reproductive performance of the cow herd.
|Calving Ease Direct (CE DIR)||Calving Ease Daughters (CE DTRS)|
|Gestation Length||Birth Weight|
Calving Ease Direct EBVs are estimates of genetic differences in the ability of a sire’s calves to be born unassisted from 2 year old heifers.
CE Dir is expressed as differences in the percentage of calves that will be born unassisted.
Calving Ease Daughters EBVs are estimates of genetic differences in the ability of a sire’s daughters to calve unassisted at 2 years of age.
CE Dtrs is expressed as differences in the percentage of daughters that will calve unassisted.
Calving difficulty scores, in association with birth weight and gestation length information, are used to calculate Calving Ease Direct and Calving Ease Daughters EBVs within Angus BREEDPLAN.
Score Code Description
If females are regularly checked during calving (e.g. on a daily basis), it is reasonable to assume that a calf who has been born without assistance between visits can be scored as unassisted (no difficulty) even though the calving was not observed. A blank score will not be interpreted as “unassisted”. Instead, it indicates that calving difficulty was not scored.
Gestation Length EBVs are estimates of genetic differences between animals in the length of time from the date of conception to the birth of the calf.
Lower Gestation Length EBVs indicate an animal is expected to produce calves that are born with a shorter gestation length.
GL is expressed in day units.
Angus BREEDPLAN will calculate Gestation Length EBVs based on the joining and birth records for calves conceived by either artificial insemination (AI) or hand mating.
Gestation length for each calf does not need to be recorded. Angus BREEDPLAN will calculate the gestation length from the joining date and date of birth information that is submitted.
Gestation length information should only be submitted for calves conceived by either AI or hand mating. Hand mating refers to situations where the female is given limited exposure to a bull (e.g. in a yard), mating occurs, and then the bull is removed.
Birth Weight EBVs are estimates of genetic differences between animals in calf weight at birth.
Lower Birth Weight EBVs indicate the animal is expected to produce progeny with lighter birth weight.
BW is expressed in kilogram units.
The weights of calves taken shortly following birth are used to calculate Birth Weight EBVs within Angus BREEDPLAN.
The weight of a calf fluctuates throughout the first week of its life. It is therefore important to weigh calves as close to birth as possible.
Many different methods are used to collect calf birth weight. These range from using bathroom scales through to the use of commercially available calf weighing cradles that can be attached to the tray of a utility or the front of a four wheel motorbike.
Birth weights should be recorded for the whole calf drop. Collecting “occasional” measurements, or only collecting birth weights for a subset of calves is of no value and can actually be misleading. Recording birth weight for dead calves is particularly important.
Unacceptable methods Birth weights collected using the following methods are not appropriate for submission to BREEDPLAN:
Weighing calves relies on mobility, ease of use and accuracy in recording the weights. There are a variety of ways to achieve this and below are some examples of the setups members use for the recording of BREEDPLAN birth weights.