Good morning, my name is Ewa Salamończyk, I am an employee of the Institute of Animal Sciences and Fisheries Faculty of Agricultural Sciences at the University of Siedlce.
The lecture is about optimizing mating plans and breeding strategies using cattle as an example.
The lecture plan is as follows. Objectives of breeding work, basic stages of breeding work, basic methods of improvement.
I will discuss the first method of improvement, which is selection.
Next, I will talk about the second method of improving cattle, which is selecting pairs for mating.
Next, I will describe the effects of implementing cattle breeding programs.
At the end, I will provide a brief summary of the topic being discussed.
The aim of animal breeding is to transform the genetic structure of the herd in a direction that meets human requirements.
These requirements focus on improving animals in terms of performance and direction of use.
In the case of cattle, such a goal could be to increase milk production or improve meat quality.
To achieve the previously selected goal, you must perform the following actions in order.
Conduct a current assessment of the herd of cows in terms of selected production traits and breeding value.
Then choose the animal species and traits that we will improve.
The next step is to select a male for breeding with the female in order to achieve the intended goal.
Improving selected traits in cattle can be done through selecting heifers or cows within the herd and evaluating and selecting bulls in the population or breed.
In cattle breeding, two basic methods are used to improve them.
Just selection and mating or crossing pairs for reproduction.
The first method of improvement, selection, is the choice of animals that will be parents of the next generation.
Offspring acquires genotype at the time of conception that remains constant throughout its life.
Therefore, the appropriate selection of parents can allow for breeding progress.
Some well-known selection methods include selecting multiple features at once or selecting based on the total value of features, known as the selection index.
In the breeding program, in addition to the established goal, the following elements are included.
Selection of fathers and mothers of bulls, followed by individual associations of selected individuals.
The offspring, or young bulls, are subjected to self-assessment.
After reaching a certain age, semen is collected from selected bulls and then used in selected herds for testing purposes.
Daughters born are evaluated for their utility value, milk production performance to determine the breeding value of test bulls.
Genetic progress in cattle is achieved through four distinct pathways.
The father-son path is where bullfathers pass on their best genes to their sons.
Introduced with much greater selectivity, as only 1% of bulls become fathers of sons.
These individuals, because there are few of them, have a significant impact on the level of inbreeding in the population in the long run.
Therefore, care should be taken to ensure that on the one hand there are few fathers of bulls, and on the other hand they are not closely related.
The path of the mother-son is the second path of improvement, on which mothers of bulls are chosen.
Traditionally, it was known for its high sharpness because there were always relatively many cow candidates.
In this pathway, it is not only important to search for the best females, but also crucial that they actually produce the desired male offspring.
The father-daughter relationship is traditionally associated by breeders with breeding work in the herd.
Breeders choose her based on their determination to select males with the highest breeding value.
Therefore, up to 70% of breeding progress in the herd depends on a well-conducted selection of bulls for cows.
In a typical course of life and productivity of a breeding bull in the conventional method, which is evaluated based on daughters, the following elements are involved.
After birth, the bull is raised, evaluated based on its own utility and suitability for breeding, and then classified into one of four classes.
Conventional evaluation of a bull's breeding value takes a long time, even up to 12 years.
Due to the significant role of bulls in genetic progress, a very important task is to accurately assess their breeding value.
We distinguish the following methods for evaluating the breeding value of bulls.
Pedigree evaluation, BLUP method and genomic evaluation.
The breeding value assessment by BLUP is expressed as deviations from the average of peers of other sires' daughters.
BLAP can be defined as the best linear, unbiased prediction.
Best, as estimated breeding values are characterized by high accuracy.
Linear, because the statistical model used to estimate breeding value is.
It relies on the cumulative effect of individual factors influencing the levels of specific traits.
unburdened, unencumbered anticipation.
Because it means that the obtained breeding values are minimally distorted.
Through the influence of non-genetic factors, this distinguishes the BLUP method from selection index.
Another method of evaluating the breeding value of bulls is genomic evaluation.
Genomic selection in dairy cattle breeding allows for the identification of genetically superior animals.
Allows for the identification of genetically superior animals at a very young age.
With greater accuracy than the genetic average value of parents.
Genomic evaluation may include a large number of young animals, allowing for more stringent selection.
Traditional scheme for evaluating the conventional breeding value in bulls
It takes about 6 years from the selection of parents to the next generation.
Do not use the bull commercially based on the evaluation obtained from his daughters.
This method is accurate but costly and time-consuming.
However, genomic evaluation allows for the valuation of very young animals.
This allows for a shorter generation gap and increased selection sharpness.
In the evaluation of bulls based on the milk performance of their offspring, mainly the following factors are taken into account:
milk yield, fat yield, protein yield, fat percentage, protein percentage
Trim the number of somatic cells.
One of the selection methods used in cattle is selection indexes.
Here are examples of such selection index constructions used for selecting bulls:
In selected countries, combining values of selected features.
In Canada, the LPI index consists of 51% milk production traits and 34% durability.
including lifespan and body type, as well as 15% of traits described as health and fertility.
In the United States, the Total Performance Index selection index consists of 36% production traits.
28% is related to health and fertility, while 26% is related to body structure traits.
On the other hand, the German selection index is even more detailed and complex.
Polish Selective Index Formula Production Functionality is the sum of indexes.
production, cutting, fertility, somatic cell breeding value
and longevity with their proper weight.
Evaluation of breeding value of bulls using the production functionality index in Poland
including the Institute of Animal Production, a state research institute,
which publishes the ranking of bulls twice a year according to the value of this index.
The best bull in terms of breeding value assessment in Poland in December 2023 was the bull CHARON.
That is all his individual subindex values in the United States.
and all its values of individual subindices from this rating.
The second method of improving cattle is through selecting pairs.
We distinguish two methods of selecting pairs.
Breeding, or the selection of animals for reproduction within one breed.
and crossing, or mating animals of different breeds.
In the case of pairing, we can talk about random or non-random pairings.
of relatives and friends.
In the case of crossbreeding, or mating animals of different breeds,
we distinguish such as selective breeding, race-mixing,
displacing, commercial and interspecies.
We will focus on pairing animals for animal matchmaking.
so that the offspring meets the breeder's expectations,
Two methods of association can be used.
Matching the best cows with the best bulls,
inferior cattle
in terms of a specific production or cutting characteristic
It is inseminated with the semen of a bull, which clearly improves this trait.
How to optimize matchmaking plans?
The most important thing in this regard is to choose the right bull.
because depending on the size of the herd we can obtain
from a few to several dozen heifers per year.
Where to start when choosing bulls and what to pay attention to,
Was the choice optimal?
First, analyze the pedigrees of cows.
Do not allow the association of related animals.
Secondly, choose the buffalo based on characteristics, ease of taming.
especially important when pairing heifers and small-breed cows.
Important tip informing the value of a buffalo
The selection index is high.
but the principle should be that the best is the one who leads,
which fits our herd,
Not the one with the highest index value.
Then, breeding values should be taken into account.
advantage over daughters' milk components,
percentage of protein as well as characteristics of appearance and structure.
When choosing a bull for mating, consider
functional aspect, previously mentioned ease of extermination and longevity.
One of the options for optimal pairing selection
is the use of a computer program.
which has deep pedigrees of cows and bulls
and takes into account genetic defects
I respect the future calves' kinship.
Computerized selection programs allow for determining
such selection parameters as optimizing one or two features.
Preliminary selection is made of bulls that have the appropriate level.
breeding values for production and functional traits.
The breeder selects the priority traits to improve.
The choice of the right number of bulls depends on the size of the herd.
degree of credibility, evaluation of breeding value
and the level of risk that the breeder is willing to accept.
Do not inseminate with the semen of one bull.
more than 15-20% of cows in the herd.
So what are the consequences of conducting breeding work in cattle populations?
These are changes in the breeding values of animals.
reduction of genetic variation,
spreading genetic defects, increasing homozygosity.
Breeding decisions related to the selection of animals for mating
unfortunately lead to an increase in inbreeding,
A 1% increase in inbreeding results in a decrease in milk yield.
During a 300-day lactation period, cows typically lose around 20 kg on average.
At the end, a few key points for summarizing the topic.
optimization of mating plans and breeding strategies
For example, cattle.
We call breeding work aimed at breeding operations.
To improve numerous traits of animals.
The main focus of improvement in cattle is functional traits.
such as lactation, proper construction,
in which the structure mentions and shapes the arrow,
useful for mechanical milking,
functional or meat utility.
For conducting breeding work, i.e. improving cattle.
knowledge of its utility and breeding value is necessary.
An assessment of the utility value of cattle is conducted for this purpose.
collecting information about cows' milk production,
chemical composition of milk and the like.
Based on this information, an investigation will be conducted.
selections, meaning animals with outstanding characteristics
with desired properties and are intended for
reproduction. Another element of breeding strategies
pairing selection. This requires
knowledge of the value of both males and females.
There are two ways of association.
Matching the best cows with the best meat
with a better association.
There are two ways of association.
Matching the best cows with the best bulls
and corrective pairing.
The most important elements considered in matchmaking
individual degree of relationship
To avoid inbreeding and breeding goal within the herd.
(production features, functional features).
Thank you for your attention.