Contributed by Charlotte Broardbridge, Neogen

Introduction

A new poll mutation, called Guarani Poll, has been discovered which helps explain why some test results on the traditional horn/poll tests do not always reflect the phenotype when it comes to Bos Indicus cattle.

The Guarani Poll variant is one of several dominant poll variants that produce the polled phenotype across different cattle populations. Based on research conducted by the University of Queensland’s (UQ) Queensland Alliance for Agricultural and Food Innovation (QAAFI) identified a previously undetected casual variant of the polled gene and developed a DNA test to identify the presence or absence of Guarani Poll.

The Guarani Poll DNA test is available to Brahman Breeders via the Australian Brahman Breeders Association (ABBA) in collaboration with long term partner Neogen.

“After years of collaborative research between QAFFI and Neogen investigating the compatibility of the current Horn/Poll test in Australian Brahman cattle, an additional test is now available to identify the presence of the Guarani poll variant. This expands Horn/Poll testing in Brahman cattle to now identify three known poll variants (Celtic, Friesian and Guarani).

We thank Neogen for their support in making the Guarani Poll test commercially available to our members, allowing them to make informed herd management decisions” – said ABBA General Manager Marsha Keily

“The Guarani Poll test has been long awaited addition to the Brahman tool kit and will give breeders more confidence in their selection decisions” – said Harry Stewart, Neogen’s Northern Genomic Beef Specialist.

Poll – Why it is not black and white

Horn Poll is not considered a “black and white” test, due to the poll locus being a haplotype.

A haplotype is a group of neighboring genes/SNPs that are located closely together on the genome. In short, poll is a “region” with the DNA made up of multiple SNPs, that influence the trait expression.

This is different to other DNA tests which are controlled by single SNPs and therefore less variation is found. Horn Poll is considered a haplotype test, and therefore controlled by multiple SNPs.

Within the poll region, there are different known poll variations including Celtic Poll, Guarani Poll, and Friesian Poll. The poll haplotype has been subject to much research to help inform producers make informed breeding and management decisions, with polledness often considered an economic trait.

Frequently asked questions

What is the difference between the current Poll test and Guarani Poll?

The current poll test offered via Neogen is the Celtic Friesian poll variant, and is the standard poll test included with the GGP testing.

The Celtic Friesian poll test is the most common poll test utilized by breeders in Australia and around the world.

There are multiple variants of poll alleles found in the poll region on the cattle genome, with other known variants being Guarani Poll and Mongolian Poll.

After extensive work by QAFFI has identified the poll alleles responsible for Guarani Poll, which has been linked to Bos Indicus cattle, in particular Nelore and Gyr cattle.

Mongolian Poll is another known poll variant, with work ongoing to develop a DNA test to identify the Mongolian variant.

When should I order Guarani Poll?

Breeders are encouraged to test for Guarani Poll if:

• Traditional Celtic Friesian Poll test results do not align with the observed horn poll phenotype
• Animals may have linkage back to known carrier lines
• There is a need to better understand inheritance patterns within breeding lines or operations
• Cattle are Bos indicus or Bos indicus based with Gyr or Nelore background

How do I order Guarani Poll?

Guarani Poll can be ordered either as an add-on test or a stand-alone test via the Australian Brahman Breeders Association (ABBA).

If you feel that your animal may be a carrier for the Guarani Poll variant, based on pedigree, and it has not been DNA tested, we would recommend selecting the Guarani Poll add-on test.

The add-on test must be ordered at the same time as another DNA test for the add-on price to be applicable.

If your animal has already been DNA tested, and you have received a Celtic Friesian Poll result that is inconsistent with their phenotype, you may need an alternative poll test to confirm which mutation your animal is carrying.

Please select Guarani Poll Standalone on your submission form.

For animals’ DNA tested within 12 months, Neogen may be able to access your previously submitted sample.

For animals DNA tested more than 12 months prior, Neogen would recommend taking a new sample for submission.

I have tested for Poll and Guarani Poll; how do I understand the results?

Neogen currently have 2 poll tests available for Brahman Breeders via ABBA:

• Celtic Friesian Horn/Poll Variant
• Guarani Poll Variant

Both tests represent different variants found in the poll region of the beef genome. If an animal has been tested for both poll variants, they will have 2 different sets of results .

Celtic Friesian Poll is the most common poll variation found in the Australian cattle population, and the DNA test for it has been widely used by cattle producers for many years.

The Celtic Poll variant can identify which 2 copies of the poll gene an animal has inherited.

There are 3 different variants Celtic Friesian Poll Mutation:

• Pc – Poll Celtic
• Pf – Poll Friesian
• H – Horned

In some instances the animals polled phenotype status does not align with the animals Celtic Friesian poll results. This may indicate that the animal is carrying a different poll variant, such as Guarani.

Results will be reported back as follows

Result	Interpretation
Pg	Guarani Poll variant present
N	Guarani Poll variant absent

Results reported inform us which variants an animal is carrying, as follows:

Result	Interpretation	Inheritance
PcPc	Homozygous Polled (PP)	A copy of Pc has been inherited from each parent
PcPf	Homozygous Polled (PP)	A copy of Pc has been inherited from 1 parent A copy of Pf has been inherited from 1 parent..
PfPf	Homozygous Polled (PP)	A copy of Pf has been inherited from each parent
HPc	Heterozygous Polled (HP)	A copy of H has been inherited from a parent. A copy of Pc has been inherited from a parent.
HPf	Heterozygous Polled (HP)	A copy of Pf has been inherited from a parent . A copy of H has been inherited from a parent.
HH	Horned (HH)	A copy of H has been inherited from each parent.

In 2026, a new DNA test has been released to assist breeders to test for the presence or absence of the Guarani Poll variant.

The current Guarani DNA test can only determine the presence or absence of the Guarani Poll variant within an animal’s genome.

Neogen cannot currently report how many copies of the Guarani Poll variant an animal has inherited/is carrying. Therefore, Neogen can only report the present or absent of the Guarani Poll variant.

When will I be able to tell if my animal is carrying multiple copies of the Guarani Poll variant?

DNA tests evolve and enhance over time with more information we obtain.

The current Guarani Poll DNA test is the first commercial DNA test for the detection of the Guarani Poll variant based on the research conducted by the Queensland Alliance for Agricultural & Food Innovation (QAAFI).

The current test can inform cattle breeders if the Guarani Poll variant is present or absent in an animal’s DNA. It cannot currently inform us how many copies (1 or 2) of the variant an animal is carrying.

Research is ongoing, and breeders are encouraged to contact Neogen or QAFFI if the results do not align with the on-farm phenotype, so further research can continue.

The aim is to further enhance the Guarani Poll test so that we can report if an animal is homozygous or heterozygous for Guarani Poll.

How can I find out more about Guarani Poll?

Please contact either the team at the Australian Brahman Breeders Australia office or the Neogen team, who can assist you in determining if the Guarani Poll test should be built into your genotyping strategy. Neogen and ABBA will continue to release education materials on DNA testing including specific subjects like Guarani Poll, so keep an eye out.