Evaluation of progeny from Simmental bulls with either top 1% or top 10% Terminal Indexes

In 2016 a study to evaluate the performance of progeny from Simmental bulls with either top 1% or top 10% Terminal Indexes was reported with full details on the NBA website. It was decided to repeat the study to find out how reliable and repeatable EBVs are.

The trial commenced in the winter of 2015 with Simmental x British Blue cows from Mr Ian Willison’s 105 head commercial autumn calving suckler herd in Nottinghamshire being inseminated with either a top 1% or top 10% terminal index Simmental bull. The calves were therefore born in the autumn of 2016 and the bull calves were intensively finished at just over 1 year old in 2017.

Comparison:

The following Simmental bulls were again chosen for evaluation:

• Dirnanean Bradley (Terminal Index +137 – top 1%)
• Omorga Volvo (Terminal Index +93 – top 10%)

The top 1% bull (Bradley) is a true ‘curve bender’ bull with easy calving and exceptional growth rate EBVs. His Calving Ease Direct EBV is +7.2 (top 1%) with a short gestation length of -2.0 days (top 5%) and outstanding EBVs for growth (+97kg for 400 days in the top 1% and +104kg at 600 days as a ‘Top Breed Value’). Bradley’s Eye Muscle Area EBV is +5.5 which is also in the top 1% for the breed. His Fat Depth EBV is -1.2mm making him a ‘lean bull’. Not only does he have superb EBVs he is also very appealing to the eye having won the Simmental breed class at the Royal Highland Show in 2014.

The top 10% bull (Omorga Volvo) is a harder calving bull with a Calving Ease Direct EBV of -5.7 (top 90% i.e. bottom 10% for the breed) but very high growth figures of +75kg for 400 days putting him in the top 5%.  

The bull calves were weaned when the cows are turned out in early April and intensively finished on good quality maize silage and blend TMR fed on a 40:60 ratio on a dry matter basis. The blend was formulated from barley, beet pulp, biscuit meal, distillers, hipro soya, maize gluten, molasses & minerals with the TMR containing 54 % DM, 12.4ME, 16.1% CP (in DM) and 28% starch (in DM). The silage and blend intakes averaged 13.5kg (4.1kg DM) and 7.2kg (6.3kg DM) per head per day respectively. The bulls were slaughtered at ABP York.

Results and conclusions:

• Overall performance of the Simmental bull calves was absolutely outstanding significantly exceeding the AHDB targets for intensive finishing suckled bulls.
• The bull calves sired by the top 1% index terminal bull recorded higher carcase daily gains (1.01 v 0.98kg), slaughter (671 v 652kg) and carcase weights (382.5 v 371.9kg) which mirrored the growth and carcase EBVs for the bulls, and mirrored the results from the 2016 study.
• The bulls were finished at just over 12 months old which almost produces a ‘cycle of perfection’ with the old calf being slaughtered when the new one is born.  
• There were no differences in carcase grades with the bulls classifying U= 3=.
• With a base carcase price of £3.50/kg the increase in carcase value of the top 1% bull sons was worth an extra £42 per bull calf taking into account penalties for heavy weights.   
• The results mirror those from the previous study indicating consistency of performance with EBVs from bulls. This is now the 7th study carried by Harper Adams to compare the performance of progeny from bulls with different Terminal Indexes. All seven have shown that with bulls with reasonably high levels of accuracy that EBVs work with significantly improved performance recorded from bulls with better figures.

For full details of the trial please download the PDF.