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Cross-Breeding Strategies for Your Beef Herd |
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Author: |
Joanne Handley - Beef Cattle
Geneticist/OMAF |
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Last Reviewed: |
08 July 2003 |
Clear targets are required when choosing what beef breeds you plan to
use in a crossbreeding program. Selection at the cow-calf level has focused on productivity per cow with emphasis on reproductive
and growth traits for the last 20-30 years. The importance of hitting the market target has resulted in the emphasis shifting
toward evaluation and selection of carcass characteristics. The first important step is to ensure your cow herd matches your
environment and resources and then determine how to hit your market targets through breed and sire selection.
The breed combination of 50% British and 50% Continental optimizes trade-offs
and fits many environments. A rotational crossbreeding system or a composite breed will work in the situation where the same
breed combinations optimize cow maternal performance and meet the optimum targets for carcass traits. In situations where
the same breed combinations do not optimize both maternal performance and targets for carcass traits, terminal sire systems
(all calves marketed, replacements purchased) should be considered because they allow the genetics of the end product to be
different from the genetics of the cow herd.
Optimum targets for carcass traits are relatively clear for larger markets
with emphasis placed on quality and yield. Two major markets with well defined targets have been identified in the Ontario
beef industry through research at the University of Guelph. The markets include beef destined for retail trade with single
A marbling and a 750 pound carcass and beef destined for the restaurant trade with AA marbling and a 650 pound carcass. Additional
niche markets may have very different targets but will be easy to define.
Researchers at the University of Guelph have calculated economic indexes
to match the market targets identified in their research. Beef Improvement Ontario has implemented the economic indexes (Beef
Builder and Prime Plus) in the bull test program to identify bulls that will produce progeny to meet those market targets.
Bulls that meet your breed criteria can then be identified by economic values for the appropriate market with further culling
based on conformation and individual traits important to your herd (i.e. birth weight, calving ease etc.). |
CROSSBREEDING BEEF CATTLE
Although
the benifits of crossbreeding have been known for many years, it has been accepted by commercial cattlemen only for the past
few years and has become a standard for the commercial industry.
To increase profitability, crossbreeding
must be used in a systematic plan, since many production benifits will result only from an organized approach.
Before designing an effective crossbreeding plan, you must have some understanding of how crossbreeding increases production.
Here at THE KUHN FAMILY FARM, We believe
that our BEEFALO have two advantages over straight bred cattle.
1. They exhibit hybrid vigor.
This directly relates to an increase in production, coupled with greater calf vigor and survival, resulting in increased calf
crops and higher weaning weights.
2. Crossbreeding can take advantage
of breed complementarity, since weakness of one breed can be offset by combining it with a breed strong in that trait.
the resulting crossbreed may not be superior in any single trait but be superior in overall performance.
A crossbreeding program that will increase
profitability must take maximum advantage of these characteristics of crossbreds. In other words, you must keep your
breeds highest qualities at the highest level possible and combine breeds that compliment each other as you create the PBP!
"Perfect BEEFALO Product"
Breeding & Reproduction
A Quick Lesson In Getting
A Cow Pregnant
Why,
if a cow doesn't ovulate until 10-12 hours after the end of standing heat do we artificially inseminate (AI) cows at the end
of standing heat? It seems like depositing the semen at time of ovulation would result in the best conception. Ron Torell,
University of Nevada Cooperative Extension Livestock Specialist, had to dig out his old reproductive physiology notes to answer
this one.
Actually, Torell says, ovulation occurs fairly consistently 24-26 hours after the onset of first standing
heat. The duration of standing heat is somewhat variable at an average duration of 10-12 hours with a range anywhere from
5-18 hours.
"It's for this reason that just detecting a cow in heat is not enough," he says. "For best conception
results one needs to know when the first standing heat occurred because the ideal time to inseminate is 10-12 hours after
that first standing heat."
This time frame translates into inseminating her 10-12 hours prior to anticipated ovulation,
he says. Identifying that first standing heat and using it as a guide for insemination timing maximizes conceptions.
"Not knowing the time
of first standing heat is why many of us have turned to the a.m./p.m. rule," Torell explains. "If a cow is detected in heat
in the a.m., inseminate her in the p.m. If a cow is detected in heat in the p.m., inseminate her in the a.m. This system works
fairly well and when you consider labor, can optimize conception results."
Okay, so why we do not inseminate at time
of ovulation?
Sperm cells (gamete) will live in the female reproductive tract from 18-30 hours. The viability decreases
after 12-18 hours. The sperm cells must go through a process called capacitation -- a term used to describe the changes undergone
by the sperm cells in the female reproductive tract.
"These changes enable sperm cells to penetrate and fertilize
an egg," Torell says. "During this time lapse, the weaker cells are weeded out or die."
Also, the hormonal changes
of the female after the last standing heat causes the reproductive tract to contract. This contraction process moves the semen
up the tract to the oviduct, the site of fertilization. This all takes time.
The egg will only survive in the oviduct
prior to fertilization for eight hours (or less). It's for this reason that the sooner (after ovulation) that fertilization
takes place the better -- so, we want the semen waiting on the egg.
So how does the bull do it? Torell explains that
in natural service situations, the bull deposits a large volume of semen in the vagina of the cow during standing heat.
"It's
due to the large volume that a few good gametes are able to migrate to the oviduct," he adds. "With AI, we deposit only one-half
cubic centimeter of semen in the uterine body. Because of the small volume of semen, we must have our timing down for fertilization
to occur."
-- Clint Peck
Livestock Management
Implant Considerations For Stockers
There are sound reasons an estimated 30-40% of stocker cattle never receive
an implant. At least a handful of them are destined for natural and specialty markets where the practice would make them ineligible.
Often times, though, according to Pete Anderson, VetLife's director of
technical services, stocker operators forego the process because the lack of facilities makes implanting impractical or impossible.
However, there are also times when the decision is based on the prejudice of perception rather than fact. As an example, Anderson
points out that if a stocker implants all his calves, it's hard to identify any additional gain because there are no non-implanted
peers for comparison.
Moreover, if there is a basis for comparison, at times folks fail to place
calves on a nutritional plane sufficient to achieve implant results. "Our rule of thumb is that if the cattle aren't gaining
at least ¾ lb./day, you won't see much benefit to implants," Anderson says. Of course, another reason some stockers shy away
from implants is worries about price discounts from buyers who may say previous implants cost them subsequent gain in the
feed yard. While the fear is real, the rationale may be suspect. For one thing, Anderson points to research conducted a couple
of years ago that indicates there were no average price differences between implanted and non-implanted cattle sold at auction;
implant history being conveyed to buyers. Apparently, buyers take proclamations from the sale block with a grain of salt.
Moreover, Anderson explains about 80% of the research data examining differences
in feedlot performance between cattle implanted or not implanted before coming to the yard show there's no difference. As
to the smaller percentage of studies indicating previous implants negatively affect subsequent feed yard performance, Anderson
suspects part of it may have to do with failing to match implant products with the class of cattle, the grass program and
arrival at the feedlot. "If we knew exactly what happened to stocker cattle on grass, in some instances we would probably
wait 30-40 days to implant them in the feedlot," Anderson says.
In other words, stacking incompatible products on top of one another could
contribute to the diminishing implant returns found in some studies. In addition to matching choice of implant products to
sex, duration on grass, performance levels and the like, Anderson says, "It's my view that the more aligned stockers can become
with feedlots, and the more aligned feedlots can become with stockers, then more trade of reliable information can be developed
and the better off both sides will be."
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