4 Reasons You Should Be Testing Your Bull’s Semen

Categories: General, Research

This week we’re putting bull semen on the table – figuratively speaking. Because after 34 years behind the microscope and 31 years in the paddock, QSML has learnt that if you’re not having your bulls tested, or buying untested bulls, it might be costing you more than you realise.

To get the conversation started, we’ve put together these top reasons why bull semen testing should form a core part of any cattle business:

1. To increase the rate of pregnancy
Morphology testing of bull sperm is a critical part of the Bull Breeding Soundness examination as it is the measure most strongly correlated with calf output.

Essentially, bulls with low percent normal sperm (PNS) get fewer cows in calf and importantly, it takes longer for the cows to become pregnant. See below graph:

Why You Should Be Testing Your Bull’s Semen(Bullpower, 2005)

What this graph tells us is that:

– Bulls with 90 PNS had 90% of the herd pregnant after 43 days.

– The bulls with 19 PNS (terrible sperm!) only had 5% of the herd pregnant after 63 days. That’s a lot of cattle, eating a lot of feed, for a fairly poor result.

2. You’ll get more weaners on the ground

20-30% of bulls fail the morphology test (a fail is anything less than 70 PNS). If you’re buying five bulls that are not morphology tested it is likely that one may have poor morphology sufficient to reduce calving rate, meaning less weaners on the ground every year.

3. Because shorter calving periods = more kilos at sale time

Bulls with a poor PNS extend the calving period. This will, in turn, reduce the kilograms sold at weaning.

A calf born at the end of a six-week joining will be 42kg lighter at weaning (at an average day gain of 1kg) than a calf born at the beginning of joining. If you look at that over 100 cows, this equates to 4,200kg! And at $3.50 per kilogram you’re looking at $14,700 lost.

4. It’s cheap!

The cost of morphology testing a bull in a commercial laboratory is less than $30.

If you’re interested in getting your bull’s swimmers tested with QSML head to our Services page or drop us a line us live via our Contact page if you’re seeking more information.

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