If you've been watching the New Zealand bull sales and trying to match the data to the price, you'll be feeling somewhat confused. Sometimes the data sells - and sells well - and then, at other times, the correlation is less obvious. This can all happen within the same sale. The reality is that buyers, particularly stud buyers, are looking for more than what's on paper. They're looking for a 'type' of animal that they believe is best suited to their properties. When the type and the data line up in the same animal, we see the big bids coming out. This is the holy grail in livestock breeding - when phenotype and data align.
The ongoing dance between traditional type assessment and data-driven breeding decisions is something that intrigues me. It's a dance I've been watching for 35 years, and I reckon it's time we got better at the choreography. For those who know me well from the very early days, you'll know that I haven't always been a breeding value fanatic. I've spent plenty of time in the show ring and still have plenty of time for the visual aspects of breeding livestock.
At this point, I feel that this much is true: the breeding values work and work exceptionally well, but they don't describe all aspects of productivity and profitability. The bits that are left undescribed tend to be the more subtle traits that take time to have an impact. Traits like constitution or doability or resilience - there are many ways of describing an animal that turns up each year and does its job. These traits are often linked to sustained reproductive performance under variable nutrition. It can be argued that these traits are covered in the current breeding values, but I think there's more to it.
What is type anyway?
That's kind of like asking how long a piece of string is. Many different people have many different versions of type. In livestock breeding, type refers to the visual assessment of an animal's physical characteristics - the way they're put together, their proportions and their strengths.
Type assessment has been around since humans first started selecting animals for breeding. Long before we had ultrasound machines measuring eye muscle depth or computers calculating breeding values, our ancestors were making breeding decisions based on what they could see and feel. They developed an eye for animals that worked in their environment, produced good offspring, and generally did the job they were bred for.
When I write it down, I can almost visualise the reader rolling their eyes. The big question is: is it even a thing? I'm not going to answer that question this early in the article, but I hope you form an opinion.
To make type something we can all imagine in our heads, I'll focus on what I've observed as being the type that Angus bull buyers are looking for in New Zealand. The bulls that get the most attention are deep-bodied, with both width and strength through the topline. They're smooth through the shoulder (without being narrow), have the perfect pastern and leg angles, and have depth of heel. Their back feet land perfectly in the imprint made by the front feet when walking. They have strong (read thick) leg bones and a deep jaw (the distance between the eye and the bottom of the jaw). They display above-average muscling through the body and walk squarely when viewed from behind. They have the perfect sheath, a big set of nuts, and are as quiet as a kitten.
The genetics of type
I've said it before, and I'll say it again: if you can dream it, you can breed it. This is true for type - all of the things I've written above are under some level of genetic control. As is the case with other traits, the problem with trying to make genetic gain in these type traits is that the environment also plays a part. I'm here to argue that if we truly want to improve these traits of type, we need to be able to differentiate good from bad and put a number on it. Once we can put a number on what our eyes are telling us, we shift from a subjective assessment to an objective assessment. To quote Jayne Reed, 'If you measure it, it moves'.
I've hunted the literature and asked a couple of different AI large language models, and I'm sad to say that I can't find anything in the literature that has studied the heritability of these traits, the environmental influence, or what they're correlated with. If any readers know of such a study, I would love to be sent a reference.
Just to be clear, I'm not suggesting that lack of scientific evidence proves that type traits aren't important - I'm just amazed that we haven't quantified these things at some point. Considering the buyer emphasis placed on some of these traits, we're well overdue to comprehensively study them to provide clarity to the industry. We're up for the challenge if we get a few breeders coming forward who would like to work with us.
The muscle paradox
The perfect example of the tension between measurement and visual assessment is muscle. For several decades, we've had eye muscle measures on sheep and beef, which have been converted to breeding values, and these point measures are moderately heritable and able to be selected for successfully. These eye muscle measures are correlated with whole-body muscling, but the problem is that the correlation is far from 1. That is, more muscle in the loin doesn't always equate to more muscle across the body.
This is an area that has received plenty of scientific rigour thanks to Bill McKiernan and a number of scientists who have supported or continued his work. This team in New South Wales set up selection lines based on a muscle scoring system and demonstrated that it's possible to genetically improve whole-body muscling by consistently scoring it. They also demonstrated that, with well-trained assessors, it was highly repeatable across ages, showing that young age assessments were very predictive of older age assessments, which is important. Linda Cafe has been involved in a lot of this work, and I'm keen to get her on the podcast to discuss it further.
Further, by converting a type trait into a scoring system, and combining the type trait with the measured trait of ultrasound muscle dimensions, it provided a better outcome than either of them on their own.
This research has also shown a range of favourable correlations with selection for muscling, including feed use efficiency and carcass weight. The thing that's most relevant for this article is that this work showed that eye muscle area only explained about half of the variation in whole-body muscling. This doesn't mean that the breeding values for eye muscle area are wrong or not useful - it just illustrates that if you want to improve something (eg whole-body muscling), you're best to select for it directly rather than rely on correlations with other traits.
Why does scoring traits matter?
You may be reading this wondering, ‘Why is he trying to overcomplicate this?’ That is, we can see the data, and astute breeders can assess the type (and other aspects of the phenotype) and make decisions about the appropriate balance in animal selection.
The problem with this approach is that it assumes that type traits and other aspects we assess in the phenotype are 100% under genetic control. That is, it ignores the impact that environment, dam age, nutrition, etc., have on what we assess as type. Considering that this isn't the case for any other trait, it seems unlikely to be true for these traits.
The other problem with assessing type and data as two separate aspects of an animal is that it's hard to retain objectivity across the selection process. It's easier to decide an animal is a cull because of a visual trait that may not be perfect than it is to cull an animal based on its objective data. Our eyes dominate the selection decisions we make.
Using a scoring system to record type, structural or other visual traits puts all traits on a level playing field. They can then be worked on, in a structured way, together. For us at neXtgen, we can put all of the traits into a bespoke index for a producer, and excellence on an index becomes a combination of measured and visual traits, rather than a process where type and data are at odds with each other. This also allows for the opportunity to break correlations that exist between type traits or between type traits and objective data. For example, many Angus breeders will tell you that selection for lower birthweight has resulted in fine-boned cattle. But if you wanted to breed for low birthweight, matched with strong-boned cattle, the best way to do it would be to score (and select for) both traits.
Objectively measuring the whisper of intuition
I think the underlying question is: Are there desirable traits in livestock breeding that are not yet adequately described by breeding values? The answer to that question is yes. Do all aspects that every breeder considers important matter? Probably not, but we won’t know without studying it.
We definitely need a body of work to understand the role that these traits play in farmability, productivity and profitability. The aspects that are found to be useful need to be fully described and incorporated into broader selection strategies. On the other hand, we need to move away from the aspects that are found to have no link to ease of farming or system profitability. The lack of information in the literature makes it difficult to predict which traits will be useful and which ones will be proven to be not so useful.
The key insight is that if something is heritable and correlates with the drivers of farm business success, we can usually find a way to measure it and improve it through selection. The challenge is developing measurement systems that capture what experienced breeders are seeing.
Recent work using computer vision and artificial intelligence is opening up exciting possibilities. Researchers are training algorithms to assess muscle pattern, structural correctness, and wool quality traits using digital images. While still in its early stages, this technology could eventually provide objective measures for many traits that are currently assessed subjectively.
The path forward for better bull selection
The answer isn't choosing between type and data, but finding better ways to quantify what our eyes are telling us. The best breeders I know use both - they understand the power of breeding values, but also trust their visual assessment of animals. The exciting opportunity ahead is to bridge this gap more effectively, turning subjective assessments into objective measurements that can be incorporated into our breeding programmes alongside our current EBVs.
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