Med. Vet. Alberto José Prando, Department production Animal-FCV-UNLP
-Genetic selection is cheap, permanent and cumulative. This means, you have to strive to achieve greater success in its use in favor of the productivity and profitability of farming systems therefore, for any decision related to the genetic improvement, It is important to have clearly defined the type of animal that is intended to, in relation to the environment (basically feeding) and the markets that it seeks to meet.
The genetic composition of commercial herds is determined in more of the 90% by the male line, is through the bulls used to long time, whether by natural service or artificial insemination. Therefore, the choice of a player is a crucial aspect for breeders, constituting a genuine HCCP, given that the consequences may be positive or negative, but always with a considerable impact.
The progeny of a father who is inevitably destined for slaughter (weaning calves, steers), It will markedly impact the productivity and profitability of livestock production systems and the third litter of children weaned from the first. This becomes more evident still, If said father transmits his great offspring growth capacity, high weight at different ages or outstanding qualities of housing.
However, It must not lose sight ever, that all parents bulls also beget daughters, which (in an amount equal to the 20% of the total number of adult sows) they will go to the annual replenishment. (See Figure 1)At this point, It is where the influence of a male as a maker of mothers of rodeo begins, which constitute the foundations of the productive capital of business incubators household, given that them depends on the number and quality of the calves weaned per crop. But unfortunately, This aspect when players are selected for commercial schemes, It is not always taken into account. Basically, This occurs because the impact on the quality of future bellies, you will notice with the passing of the years, and not in the short term, as is the case with regard to growth and housing. In fact, When Bulls with a genetic background that generates a quality female progeny are chosen, maximum benefits will newly be notice to the 10 years of that decision. This is due, the accumulation of successive litters of daughters and that they will have reached the maximum productive potential (basically expressed as kg. weaned calf). (See Figure 2)
How to choose the best sire of bellies functionally
In limited, breeding cows must be fertile and long-lived, to achieve the greater efficiency reproductive and the lower rate of replenishment. One way to achieve this is through rodeo parents adapted to different environments, selected through a functional biotype that induces to have a correct biological performance. Parameters to take into account:
General appearance: Always healthy as synonymous of absence of diseases
Peleche: An early peleche is indicative of total adaptation of the ranch to a certain ambiance.
Mucous: They must always be Pigmented.
Secondary sex characteristics: A sexually correct Bull will produce well female daughters. The musculature is well developed and prominent throughout the body. The hair should be short, shiny and not black animals, darker on the face, pallets, cross, ventral part of the trunk and hind quarters.
Depth: Deeper is better an animal, Since it implies a greater breadth of the thoracic and abdominal cavities that contain cardio-respiratory and digestive apparatus, respectively. A good rumen development is necessary as a fermentation VAT, because breeding has assigned low digestibility forages (high lignin content).
Ocular pigmentation: The coloration of the skin and hairs surrounding the eye is recommended (blinders), to decrease the incidence of tumors and kerato-conjunctivitis (Hereford, Braford).
Scrotum, testicles: Bulls with these proper organs will produce females with functional genital appliances. At the same time, We will have to select those parents with high scrotal circumference measurements, given that their daughters will be sexually more precocious and will have a greater reproductive efficiency throughout its useful life.
Sticking: The inclusion of very high tail is associated with animal's paw stopped by what pelvic floor loses its natural back and down tilt. A high sticking difficult removal of the postpartum Lochia, promoting metritis and thus infertility.
Limbs:
to) Former members: The limbs line passes by the end of the humerus and falls perpendicularly to the ground in the interdigital space of the hoof. As default, It may happen that the knees are ahead of that line ("planted hands") or to do so from behind ("joining hands"). Looking at the animal's front must be observed that the limbs line passing through the Centre of the knee and lower to the interdigital space. As default seen closed knees ("zambo") or open ("chueco").
b) Hind limbs: The limbs line must fall perpendicularly to the ground through the bones and touching the paw. When the garron is located ahead of the line of limbs the animal is "stop garron", raising the rump and the sticking. In reverse, If the garron falls ahead of plumb-line the animal is "sitting of garron". Looking at the hind limbs from the back, If the paw are inward is a closed individual of paw and otherwise is an open animal's paw.
c) Foot: The pastern angle should oscillate at 45 ° with respect to ground, why you should avoid very long pages (decreases the angle) or too short (increases the angle).
Temperament: Tame animals imply greater safety for field staff, professionals and facilities. Quiet individuals gain weight easier and the quality of meat is superior.
Fertility and longevity of the bellies are characters that have a significant impact on the profitability of farming and not always fully conscious of them is taken. Fortunately, There is a very simple and cheap way to consolidate them at the rodeo, as the incorporation of bulls is parents selected by functional efficiency.
Fig. 1: Impact of a bull at the rodeo through time (Parnell. P, 2003)
Fig. 2: Economic benefits over time by use of a bull through their faenada progeny and their daughters (Parnell.P, 2011)
