Delayed Blindness also known as CLN is an autosomal recessive condition that causes retinal degeneration within the eye. Affected animals are not born blind, but vision loss is noticeable around 9 to 12 months of age.  Animals have increasing difficultly navigating their surroundings.

Mandibulofacial Dysostosis is an autosomal recessive condition that causes affected calves to be born with facial deformities, and may include cleft palate, short jaw, crooked jaw, or face. The ears are sometimes slightly small and floppy. Calves are born alive but fail to thrive, often due to difficulties with nursing.

BVD is a virus that is widespread in New Zealand cattle and causes reproductive losses, weak calves, reduced growth rates, lowered milk production and increased susceptibility to other diseases. BVD spreads through close contact with infected cattle. Persistently infected (PI) animals in the herd present the highest risk as they shed large amounts of virus throughout their lives. BVD can also be introduced through purchased, leased, borrowed or returning stock.

Poll/horn testing identifies whether an animal carries the genetic variant for polled (hornless), scurred (small, loose horn-like growths) or horned traits. The polled allele (P) is dominant to the horned allele (H) which means only animals that are homozygous recessive (HH) will be horned. Animals that are homozygous dominant polled (PP) will only produce offspring that are polled; whereas animals that are heterozygous polled (PH) will appear polled (or scurred) but can produce horned offspring if mated to another heterozygous polled animal or a horned animal. 

The MC1R gene, also known as the Extension locus, controls the production of black (eumelanin) and red (phaeomelanin) pigments. There are three alleles (forms) of this gene:

Dominant black (E^D) – this allele is dominant over both the other alleles so animals will have black coats if they have one E^D copy.

Neutral Wild type (E⁺) – varied colours, but reddish brown if animal is E⁺/e.

Recessive red (e) – all homozygous recessive animals will have red coats.

 

Bulldog dwarfism (BD1) is a lethal autosomal recessive mutation. Affected animals are aborted or stillborn. Heterozygous animals (carriers) are born alive and live but have a mild form of dwarfism.

Hypotrichosis is an autosomal recessive mutation in the KRT71 gene that causes congenital hairlessness. Affected calves are often born hairless, or with very short, fine, woolly, kinky, or curly hair that may result in complete or partial loss of hair leaving bare patches.

Idiopathic Epilepsy is a lethal autosomal recessive condition that causes calves to experience seizures. The age of onset can vary from birth to several months of age. Affected animals are seen recumbent on their side with limbs extended in a rigid state. The seizures may last from several minutes up to more than an hour. Primarily seen in horned Herefords, as well as polled Herefords that have horned animals in their pedigree.

Maple Syrup Urine Disease is a lethal autosomal recessive condition that causes a defect in an enzyme that breaks down complex amino acids in the diet, causing a build-up that results in lethal brain damage. Affected calves are typically born without symptoms, but by 2 to 4 days old become slow, dull and eventually recumbent. The calf will often throw its head back and lie on its side, unable to rise.

Coat dilution is a mutation in the PMEL17 gene which causes a moderate or incomplete dilution of red and black pigmentation based on its interaction with the MC1R coat colour gene. Dilution is a dominant trait.  In Hereford cattle the gene causes dilution to black pigmentation leading to grey, smoky, or chocolate coat colours when carrier animals are crossed with black cattle (e.g. Friesian or Angus). Hereford cattle can carry the Dilutor mutation but will show no outward signs as they do not have any black pigment.

Tenderness is a complex trait influenced by muscle properties and the conditions that occur within the muscle after slaughter; it is a function of connective tissue, marbling or intramuscular fat, and postmortem protein degradation known as the calpain-calpastatin system. Calpain316, Calpain4751, and Calpastatin alleles are associated with more tender meat.