Page 21 - MWC 3-30-2023s

The Midwest Cattleman · March 30, 2023 · P21

Planned Crossbreeding Systems

By Joe W. Mask, PhD., Beefmaster Breeders United Executive Vice President
Beef producers are always from the other breed. With erosis=((700-662.5)/662.5) producer. Maternal hetero-
looking for a way to increase this in mind, an F1 animal X100=5.7%. sis is extremely important in
the profitability of their op- has the maximum amount of Taking full advantage the overall productivity of the
erations. To do this they use direct heterosis and a F1 dam of heterosis is done when a cow, impacting things such as
selection criteria that will has the maximum amount of system is in place that uti- fertility and longevity, both
help them increase weaning maternal heterosis. lizes a crossbred female to of which lead to more calves
weights, yearling weight, rib Direct heterosis will affect produce crossbred calves. that are raised by a cow in
eye area, marbling, stayabili- and improve most traits in a There are different cross- her lifetime. The more calves
ty, and pregnancy rates. Many calf. Heterosis has the most breeding systems that are a cow can raise in her lifetime
times, producers look at EPDs effect on lowly heritable traits very successful at utilizing makes her more valuable to
and recorded weights and but will also be observed on and maximizing both types the producer. Another way to
records to do this, and those weight traits which are mod- of heterosis. Direct hetero- help effectively utilize hetero-
are very valuable numbers in erately heritable and carcass sis is important because it sis is to use cattle that are Bos
the selection process, but one traits which are highly her- directly impacts the weight indicus influenced, Bos indi-
thing that may get overlooked itable. With these moderate- and carcass traits of the calf cus X Bos taurus cross cattle
sometimes is the value of ly heritable traits, the level and increased weight and tend to exhibit a higher level
crossbreeding. Crossbreeding of heterosis to be expected is better carcass traits lead
helps to optimize these traits moderate, from 5-10% and to increased profits for the continued on page 22
and can be a simple tool when with the highly heritable
used in a thought-out cross- traits the level of heterosis to
breeding system. be expected is around 0-10%.
Maternal heterosis is ex-
Advantages of tremely important because
Crossbreeding
Crossbreeding provides two many of the maternal traits
advantages to using straight are lowly heritable traits. Re-
bred animals, first there is production, maternal abili-
ty, longevity, and other traits
heterosis or hybrid vigor and
the second advantage is breed that deal with overall cow
productivity are lowly herita-
complementarity (in a prop-
erly designed system). Breed ble traits and heterosis has
the greatest effect on lowly
complementarity is taking
advantage of the strengths heritable traits. The expected
levels of heterosis for these
of the differentbreeds used in
the system. In a well-designed lowly heritable traits typically
ranges from 10-30%.
crossbreeding system, the pro-
To calculate the level of het-
ducer can maximize the effect erosis the equation is: Level of
of both of these advantages.
Heterosis is the ability of Heterosis=((Average of cross-
the cross bred offspring to bred animal-average of par-
outperform the average of the ent breeds)/average of parent
breeds)X100. For example, if
two parent breeds. There are
two types of heterosis to take level of heterosis is being cal-
culated for weaning weight
advantage of, direct and ma-
ternal heterosis. Direct het- in a Beefmaster X Angus
cross and the average wean-
erosis refers to the heterosis
of the animal itself, and ma- ing weight on the particular
Beefmaster used is 675 and
ternal heterosis refers to the
heterosis of the dam of the the average for the particular
Angus used is 650, and the
animal. The amount of het-
erosis can be estimated by the average weaning weight of
the calves is 700 pounds the
percent of heterozygous gene
pairs, where one gene comes level of heterosis can be calcu-
lated to be 5.7%. Level of Het-
from one breed and another