How Traits are Inherited:
All cells in the body have these "blueprints" that will tell how an animal will look or act. What an animal looks like depends on the genes from both his sire and dam. All animals receive half of the genes from their sire and the other half from their dam. How an animal looks as a result is different from what is in his genes. Phenotype is, by definition, the physical characteristics of an animal. Genotype is in reference to the type of genes that has animal has that cannot be seen unless that animal is bred to another animal of similar phenotype or has his/her DNA tested.
Some more definitions to know:
Homologous chromosomes - chromosomes that are duplicated (or a pair of chromosomes). Cattle have 30 pairs or homologous chromosomes. Humans only have 23 pairs.
Chromosomes - a threadlike structure found in the nucleus of a cell that carry genetic information in the form of genes
Gene - The portion of the DNA molecule or chromosomes.
Allele - Genes that occupy the same location on homologous chromosomes.
Qualitative Traits:
These are traits that are affected by a single pair of genes. Such traits that are affected in cattle are presence of horns and coat colour. The basic colours found in cattle are Black, Red, and Reddish Brown to Brownish Black.
Breeds that come in Black include:
Angus (Black Angus to some of you)
Brangus
Irish Black
Welsh Black
Galloway
Simmental
Limousin
Maine Anjou
Gelbvieh
Dexter
Corriente
The alleles best used to express the black gene is BB.
Breeds that are Red include:
Red Angus
Hereford
Santa Gertrudis
Gelbvieh
Limousin
Shorthorn
Salers
Santa Cruz
Beefmaster
The allele best used to express the red gene is bb.
Those breeds that are Reddish-brown to Brownish-black (or Wild-type) are:
Jersey
Brown Swiss
Brahman
Longhorn
Dexter
Scottish Highland
Brahman
Braunvieh
Chianina
Canadienne
The allele best used to express this gene is B'B'.
Black is dominant over red and brownish red. Brownish red is dominant over red. Red is the most recessive gene of all three allele types.
Dominant genes refers to that one gene that tends to overshadow the expression of the other gene it is paired with. Heterozygous animals are those animals that have two different alleles but one allele is dominant over the other. This is most obvious when an Angus cow is bred to a Red Angus bull, resulting in a black calf. The calf has both the black and red alleles, but since the black allele is dominant, phenotypically this is the one that is physically expressed.
Recessive genes are those genes that are always overshadowed by a more dominant gene. The only way these genes can be expressed is when they are both present on the homologous chromosome, which ishomozygous. Red coat colour = bb and Horns = hh are those genes in cattle that are recessive. Dominant genes can also be homozygous if both genes are present on the chromosome. (See Expected Coat Colour of Calves below)
Patterns and Breeds:
Spotting colourations include White Face (Wf), Spotted (Sp), Dorsal Stripe (Ds), and Solid Coloured (S)
White Face cattle are primarily a trait exclusive to Herefords, but is also present in Simmentals. There are two genes of this trait (WfWf)
Spotted coloration is a trait expressed in Guernseys, Simmentals, Holsteins, Montbeliard, Ayrshire etc. There are two genes of this trait (SpSp).
Dorsal Stripe colouration is a trait expressed in Charolais, Pinzgauers, Texas Longhorns, Gloucester, etc. There are two genes of this trait (DsDs)
Solid Coloured cattle include Angus, Red Angus, Dexter, Galloway, Highland, etc. There are two genes of this trait (SS)
Spotting Mode of Colouration (Dominance)
Wf is not dominant over Ds, nor vice versa. Both genes are expressed.
Wf is incompletely dominant over S.
Wf is dominant over Sp.
Ds incompletely dominant over S.
S dominant over Sp.
Some examples of No Dominance, Incomplete Dominance and Complete Dominance:
Hereford (Wf) x Pinzgauer (Ds) = WfDs = Hereford markings with a dorsal stripe. (No dominance)
Hereford (Wf) x Angus (S) = WfS = Solid with White face (Incomplete dominance) This is why most calves from a Hereford-Angus or Hereford-Red Angus cross are not entirely white-faced, but rather brockled (or have a white face with solid patches).
Angus (S) x Pinzgauer (Ds) = SDs = Solid with striped tail or lined back (Incomplete dominance)
Angus (S) x Simmental (Sp) = SSp = Solid
Pigment Dilution Genes:
There are three breeds that tend to have dilution genes: Charolais (Dc), Simmental (D) and Shorthorn (R).
Charolais Dilutants include having the White/Cream colouration (expressed as bbDcDc), and Skunk Tail (SSp). Dilution in calves can also be found when Angus x Charolais or Red Angus x Charolais.
Simmental Dilutants include Fawn pigmentation (DD), Moderate pigmentation (Dd), or Dark pigmentation (dd).
Shorthorns have an incomplete dominance gene. For instance, if a red bull was crossed with a white cow, they would produce a roan calf.
Brindle Colouration
Most coloured breeds have the brindle gene. However it is only expressed when the Reddish-Brown to Brownish Black gene (B') gene is present, like that in Brown Swiss, Jersey, Brahman, Braunvieh, Chianina, etc.
Brindle is a colour pattern where stripes are formed on the animal's body. This is also known as Tiger-Striped.
It should be noted (from Genetics of Colour Variation paper) that Brindle is a separate gene all on its own and does not necessarily mean that because the B' is present, there's going to be brindling. Yes, the brindle pattern can only be expressed when the wild-type (reddish-brown to brownish black) pigment is present, but is suppressed by both the black and red alleles. However, the brindle allele in breeds such as Hereford, Red Angus and Angus cattle is expressed in high frequency, so much so that when crossed with wild-type animals, there is almost always going to be offspring with the brindle coloration.
Expected Colour of Calves from Mating:
Note from above: B = black, b = red, B' = reddish-brown to brownish black, Wf = White face, Sp = spotted, Ds = dorsal stripe, S = solid
Black White Face (BWF) would be a result of breeding Hereford to Angus, creating an F1 crossbred calf.
Black x Black = Black (some red)
BB x BB = 100% BB
BB x Bb = 50% BB or 50% Bb
Bb x Bb = 25% BB, 50% Bb or 25% bb
Black x Red = Black (some red)
BB x bb = 100% Bb
Bb x bb = 50% Bb or 50% bb
Red x Red = Red
bb x bb = 100% bb
Black x Brownish-black to Reddish Brown = Black (some brindle)
BB x B'B' = 100% BB'
BB' x B'B' = 50% BB' or 50% B'B'
Red x Brownish-Black to Reddish-Brown = Brownish-Black to Reddish-Brownish-Black (some brindle or red)
bb x B'B' = 100% B'b
B'b x bb = 50% B'b or 50% bb
Black x Hereford (Solid Red & White face) = Black White Face (some Red White Face)
SSBB x WfWfbb = 100% SWfBb
SSBb x WfWFbb = 50% SWfBb or 50% SWfbb
Black x Black White Face = Black White Face, Black Mottled (maybe some Red White Face or Solid Red)
SSBB x SWfBb = 25% SSBB, 25% SSBb, 25% SWfBB, 25% SWfBb (Note: those animals with the SWfBB would most likely be the ones that are mottled)
SSBb x SWfBb = 1 SSBB: 2 SSBb: 1 SSbb: 2 SWfBb: 1 SWfBB: 1 SWfbb or 3:3:1:1 for Solid Black, BWF, Solid Red and RWF respectively.
Black White Face x Hereford = 50% Black White Face, 50% Red White Face, and some BWF & RWF have Hereford markings
SWfBb x WfWfbb = 25% SWfBb, 25% SWfbb, 25% WfWfBb, 25% WfWfbb (the animals with WfWf genotype would be the ones with the Hereford markings)
Black White Face x Solid Red = Solid Black, Solid Red, Black White Face and Red White Face
SWfBb x SSbb = 25% SSBb, 25% SSbb, 25% SWfBb, 25% SWfbb
Black x Yellow Spotted = Grey Blaze Face (maybe Yellow Blaze)
Black x Dark Red Spotted = Black and Charcoal Blaze Face
Black x Charolais = Grey with a Black Nose (maybe some Light Yellow colouration)
Hereford x Charolais = Light Yellow White Face
Black x F1 Char-Angus = Black, Grey and Light Yellow (with some skunk tails)
Charolais x Black White Face = Grey and Yellow (some White Face), some skunk tails, and some with black and BWF.
Interpreted from the Color Inheritance in Beef Cattle and Color Patterns in Beef Cattle
All cells in the body have these "blueprints" that will tell how an animal will look or act. What an animal looks like depends on the genes from both his sire and dam. All animals receive half of the genes from their sire and the other half from their dam. How an animal looks as a result is different from what is in his genes. Phenotype is, by definition, the physical characteristics of an animal. Genotype is in reference to the type of genes that has animal has that cannot be seen unless that animal is bred to another animal of similar phenotype or has his/her DNA tested.
Some more definitions to know:
Homologous chromosomes - chromosomes that are duplicated (or a pair of chromosomes). Cattle have 30 pairs or homologous chromosomes. Humans only have 23 pairs.
Chromosomes - a threadlike structure found in the nucleus of a cell that carry genetic information in the form of genes
Gene - The portion of the DNA molecule or chromosomes.
Allele - Genes that occupy the same location on homologous chromosomes.
Qualitative Traits:
These are traits that are affected by a single pair of genes. Such traits that are affected in cattle are presence of horns and coat colour. The basic colours found in cattle are Black, Red, and Reddish Brown to Brownish Black.
Breeds that come in Black include:
Angus (Black Angus to some of you)
Brangus
Irish Black
Welsh Black
Galloway
Simmental
Limousin
Maine Anjou
Gelbvieh
Dexter
Corriente
The alleles best used to express the black gene is BB.
Breeds that are Red include:
Red Angus
Hereford
Santa Gertrudis
Gelbvieh
Limousin
Shorthorn
Salers
Santa Cruz
Beefmaster
The allele best used to express the red gene is bb.
Those breeds that are Reddish-brown to Brownish-black (or Wild-type) are:
Jersey
Brown Swiss
Brahman
Longhorn
Dexter
Scottish Highland
Brahman
Braunvieh
Chianina
Canadienne
The allele best used to express this gene is B'B'.
Black is dominant over red and brownish red. Brownish red is dominant over red. Red is the most recessive gene of all three allele types.
Dominant genes refers to that one gene that tends to overshadow the expression of the other gene it is paired with. Heterozygous animals are those animals that have two different alleles but one allele is dominant over the other. This is most obvious when an Angus cow is bred to a Red Angus bull, resulting in a black calf. The calf has both the black and red alleles, but since the black allele is dominant, phenotypically this is the one that is physically expressed.
Recessive genes are those genes that are always overshadowed by a more dominant gene. The only way these genes can be expressed is when they are both present on the homologous chromosome, which ishomozygous. Red coat colour = bb and Horns = hh are those genes in cattle that are recessive. Dominant genes can also be homozygous if both genes are present on the chromosome. (See Expected Coat Colour of Calves below)
Patterns and Breeds:
Spotting colourations include White Face (Wf), Spotted (Sp), Dorsal Stripe (Ds), and Solid Coloured (S)
White Face cattle are primarily a trait exclusive to Herefords, but is also present in Simmentals. There are two genes of this trait (WfWf)
Spotted coloration is a trait expressed in Guernseys, Simmentals, Holsteins, Montbeliard, Ayrshire etc. There are two genes of this trait (SpSp).
Dorsal Stripe colouration is a trait expressed in Charolais, Pinzgauers, Texas Longhorns, Gloucester, etc. There are two genes of this trait (DsDs)
Solid Coloured cattle include Angus, Red Angus, Dexter, Galloway, Highland, etc. There are two genes of this trait (SS)
Spotting Mode of Colouration (Dominance)
Wf is not dominant over Ds, nor vice versa. Both genes are expressed.
Wf is incompletely dominant over S.
Wf is dominant over Sp.
Ds incompletely dominant over S.
S dominant over Sp.
Some examples of No Dominance, Incomplete Dominance and Complete Dominance:
Hereford (Wf) x Pinzgauer (Ds) = WfDs = Hereford markings with a dorsal stripe. (No dominance)
Hereford (Wf) x Angus (S) = WfS = Solid with White face (Incomplete dominance) This is why most calves from a Hereford-Angus or Hereford-Red Angus cross are not entirely white-faced, but rather brockled (or have a white face with solid patches).
Angus (S) x Pinzgauer (Ds) = SDs = Solid with striped tail or lined back (Incomplete dominance)
Angus (S) x Simmental (Sp) = SSp = Solid
Pigment Dilution Genes:
There are three breeds that tend to have dilution genes: Charolais (Dc), Simmental (D) and Shorthorn (R).
Charolais Dilutants include having the White/Cream colouration (expressed as bbDcDc), and Skunk Tail (SSp). Dilution in calves can also be found when Angus x Charolais or Red Angus x Charolais.
Simmental Dilutants include Fawn pigmentation (DD), Moderate pigmentation (Dd), or Dark pigmentation (dd).
Shorthorns have an incomplete dominance gene. For instance, if a red bull was crossed with a white cow, they would produce a roan calf.
Brindle Colouration
Most coloured breeds have the brindle gene. However it is only expressed when the Reddish-Brown to Brownish Black gene (B') gene is present, like that in Brown Swiss, Jersey, Brahman, Braunvieh, Chianina, etc.
Brindle is a colour pattern where stripes are formed on the animal's body. This is also known as Tiger-Striped.
It should be noted (from Genetics of Colour Variation paper) that Brindle is a separate gene all on its own and does not necessarily mean that because the B' is present, there's going to be brindling. Yes, the brindle pattern can only be expressed when the wild-type (reddish-brown to brownish black) pigment is present, but is suppressed by both the black and red alleles. However, the brindle allele in breeds such as Hereford, Red Angus and Angus cattle is expressed in high frequency, so much so that when crossed with wild-type animals, there is almost always going to be offspring with the brindle coloration.
Expected Colour of Calves from Mating:
Note from above: B = black, b = red, B' = reddish-brown to brownish black, Wf = White face, Sp = spotted, Ds = dorsal stripe, S = solid
Black White Face (BWF) would be a result of breeding Hereford to Angus, creating an F1 crossbred calf.
Black x Black = Black (some red)
BB x BB = 100% BB
BB x Bb = 50% BB or 50% Bb
Bb x Bb = 25% BB, 50% Bb or 25% bb
Black x Red = Black (some red)
BB x bb = 100% Bb
Bb x bb = 50% Bb or 50% bb
Red x Red = Red
bb x bb = 100% bb
Black x Brownish-black to Reddish Brown = Black (some brindle)
BB x B'B' = 100% BB'
BB' x B'B' = 50% BB' or 50% B'B'
Red x Brownish-Black to Reddish-Brown = Brownish-Black to Reddish-Brownish-Black (some brindle or red)
bb x B'B' = 100% B'b
B'b x bb = 50% B'b or 50% bb
Black x Hereford (Solid Red & White face) = Black White Face (some Red White Face)
SSBB x WfWfbb = 100% SWfBb
SSBb x WfWFbb = 50% SWfBb or 50% SWfbb
Black x Black White Face = Black White Face, Black Mottled (maybe some Red White Face or Solid Red)
SSBB x SWfBb = 25% SSBB, 25% SSBb, 25% SWfBB, 25% SWfBb (Note: those animals with the SWfBB would most likely be the ones that are mottled)
SSBb x SWfBb = 1 SSBB: 2 SSBb: 1 SSbb: 2 SWfBb: 1 SWfBB: 1 SWfbb or 3:3:1:1 for Solid Black, BWF, Solid Red and RWF respectively.
Black White Face x Hereford = 50% Black White Face, 50% Red White Face, and some BWF & RWF have Hereford markings
SWfBb x WfWfbb = 25% SWfBb, 25% SWfbb, 25% WfWfBb, 25% WfWfbb (the animals with WfWf genotype would be the ones with the Hereford markings)
Black White Face x Solid Red = Solid Black, Solid Red, Black White Face and Red White Face
SWfBb x SSbb = 25% SSBb, 25% SSbb, 25% SWfBb, 25% SWfbb
Black x Yellow Spotted = Grey Blaze Face (maybe Yellow Blaze)
Black x Dark Red Spotted = Black and Charcoal Blaze Face
Black x Charolais = Grey with a Black Nose (maybe some Light Yellow colouration)
Hereford x Charolais = Light Yellow White Face
Black x F1 Char-Angus = Black, Grey and Light Yellow (with some skunk tails)
Charolais x Black White Face = Grey and Yellow (some White Face), some skunk tails, and some with black and BWF.
Interpreted from the Color Inheritance in Beef Cattle and Color Patterns in Beef Cattle