Reproduction or fertility is the most important economic trail in beef cattle. Breeders are urged to record reproductive performance in both the female and the male and to build these data into their herd records. They are urged to use these data to monitor reproductive performance and to identify areas to concentrate efforts to improve performance.
As breeders are successful in selecting to increase growth rate, the importance of measuring reproduction may increase. Minimum nutritional requirements will be higher to maintain reproductive performance in faster growing cattle. Management and environment have a significant effect on the reproductive performance in faster growing cattle. Management and environment have a significant effect on the reproductive performance of the female as shown by low heritability estimates for general reproductive performance. Thus, the recording and use of reproductive performance data are an important part of the breeder’s program.
Additional research is needed on reproductive traits and measures for further refinement and improvement.
2.1.4: Calving difficulty or ease. Record with the following scores:
Score 1--No difficulty, no assistance.
Score 2--Minor difficulty, some assistance.
Score 3--Major difficulty, usually mechanical assistance.
Score 4-Caesarean section or other surgery.
Score 5--Abnormal presentation.
Note:Scores 1 through 4 may be averaged for data summarization (such as national cattle evaluations), but score 5 should not be included in averages. Although they contribute to calving difficulty, abnormal presentations do not appear to be related to the genotypes of the calf (sire and dam direct contributions) or the dam. Thus, inclusion of abnormal presentation data in any genetic evaluation would be biased.
Dystocia or calving difficulty influences economics of a cowherd in several ways. If calf losses result from delayed or difficult birth, the production from the dam is lost for the year, and the cost of her maintenance must be accounted for by the cows which actually wean calves. Labor and veterinary costs related to assisting a cow also reduce economic returns. Also, research has shown that cows which require assistance at calving do not rebreed as efficiently as cows which calve unassisted. Thus, producers are encouraged to keep and use calving difficulty records in their management and selection programs. Calving difficulty or ease can be partly attributed to the sires involved.
2.1.6: Calf history. Record as follows:
Score 1--Calf alive at weaning.
Score 2--Calf sold before weaning.
Score 3--Calf alive at 72 hours, but dead before weaning.
Score 4--Calf alive at birth, but dead within 72 hours.
Score 5--Calf dead at birth.
Calf history scores identify where losses occur if every cow does not wean a calf.
2.1.7: Cow reproduction or disposal history. This record is made each year for all cows, starting with the previous year’s breeding season. The records are summarized after weaning of calves for the past year’s breeding and calving history. Record as follows:
Score 1--Cow open, sold.
Score 2--Cow open, kept alive.
Score 3--Cow open, died.
Score 4--Pregnancy unknown, sold.
Score 5--Pregnancy unknown, died.
Score 6--Pregnant, sold before calving.
Score 7--Pregnant, died before calving.
Score 8--Pregnant, aborted.
Score 9--Cow calved.
This history of each cow for the calf crop just weaned identifies when success or failure occurred in weaning a live calf, as well as disposals of cows from the herd.
2.1.11: Yearly prolificacy. Record yearly as follows:
Score 1--Cow had one calf.
Score 2--Cow had twins.
Score 3--Cow had triplets, quadruplets, etc.
Prolificacy scores will be helpful in determining which cows have had multiple births and which sires have female relatives with multiple births, thus providing data for selection for twinning. These data also provide a base for research in twinning as a method for increasing rate of reproduction.
