How to Improve the Production of Beef in the Us
Genetic Practices to Improve
Beef Cattle Reproduction
Darrh Bullock
Academy of Kentucky
dbullock@uky.edu
*Click hither for printable pdf version.
Summary: Reproduction is typically a lowly heritable trait, but there are genetic practices that can help improve reproduction rates.
Introduction
Reproduction has a dandy bear upon on the profitability of beef cattle producers and is therefore an of import consideration when making genetic management decisions. Due to the low heritability of most reproductive traits many producers feel in that location is little that tin can be done through genetic management and rely solely on other management practices such equally health programs and nutrition direction. While nutrition and health are critical to expert reproductive rates, this publication will focus on genetic practices that can take a positive impact on reproduction.
Crossbreeding
The single best genetic management tool available for improved reproduction in commercial beef operations is crossbreeding. By implementing a crossbreeding plan combining ii or more than breeds, commercial producers tin take advantage of both heterosis (hybrid vigor) and breed complementarity. (For more than on information on crossbreeding please meet fact sheet 2014-five.)
Heterosis
Heterosis is the benefit gained when ii or more breeds are crossed. The benefit is realized based on how genes for a trait combine, with there being a benefit for the two genes coming from dissimilar ancestral (brood) origins. Heterosis has the greatest impact on lowly heritable traits, such as reproduction. There are 3 basic types of heterosis: private (affecting the calf), maternal (affecting the dam) and paternal (affecting the sire). Each of these types of heterosis tin can have an touch on on herd fertility. The influence of individual heterosis on reproductive traits is improved live births and survival to weaning. Maternal heterosis positively impacts reproductive traits such as formulation charge per unit, live births and survival to weaning, along with other of import economic traits. Little is known virtually the impact of paternal heterosis on reproduction but probable has a positive bear on on serving capacity. Encounter Tabular array i for specific levels of heterosis and its potential touch on.
| Tabular array ane. The units of improvement and percent heterosis for Calving Rate and Survival to Weaning. |
 |
Pick
Selection for improved reproduction has often been ignored because of the depression heritability of most reproductive traits. The greatest impact a producer tin have on reproductive traits is through management practices such every bit proper nutrition, a good health program and a crossbreeding organisation. However, there are nevertheless opportunities to ameliorate reproductive efficiency through pick and due to the economic bear on of reproduction these opportunities should not exist ignored.
EPDs
Regardless of the heritability of a trait, the most effective means to make genetic improvements through pick is by using Expected Progeny Differences (EPDs). Current EPDs that allow producers to select for improved reproduction are Stayability, Heifer Pregnancy Charge per unit and xxx-month Pregnancy Rate. Individual breed associations determine which, if any, reproduction EPDs they compute.
Stayability – predicts the probability of a bull's daughters delivering a dogie every yr until 6 years of age. Higher EPD indicate a college percent of daughters remaining productive in the herd until 6 years of age.
Heifer Pregnancy – predicts the probability of a bull's daughters becoming pregnant as commencement-calf heifers during a normal breeding season. College EPD indicate a college per centum of pregnancies.
thirty-month Pregnancy – predicts the probability that a bull's daughters will become pregnant and calve at iii years of age, assuming they calved equally a two-year one-time. College EPD indicates a higher percent of a sire's daughters will calve at three years, of the ones that calved as 2-year olds.
Scrotal Circumference – measure of genetic merit for scrotal circumference. Higher EPD indicates bull calves volition have larger scrotal circumferences. Scrotal circumference has been linked with increased serving chapters of the balderdash. Seedstock producers should utilize Scrotal Circumference EPDs to assist in breeding bulls with larger scrotal circumferences; however, commercial producers should be purchasing bulls with larger actual scrotal circumferences to take reward of their increased serving capacity.
Whole Herd Reporting (WHR)
Whole Herd Reporting, Total Herd Reporting, Total Herd Enrollment are all examples of inventory based methods of reporting data on all animals in the herd. The decision to mandate WHR is the sole responsibility of the brood association and there are different guidelines for each association. For specific information on a brood please refer to their website. In general, this is a concept aimed at getting a college per centum of data reported for inclusion in the breed'southward genetic evaluation. Typically with WHR, fees are spread over the entire herd instead of only those that are registered, which encourages data to be reported on all animals and reduces selective reporting. WHR improves the reliability of EPDs in full general, only is especially important for calculating reproduction EPDs. With conventional reporting methods if data is missing it is impossible to know if that is because a calf was not born or the producer simply chose non to report the data. With WHR missing data indicates a calf was not born. For traits such equally Stayability, Heifer Pregnancy and 30-month Pregnancy, where noesis of a successful or unsuccessful pregnancy is critical, WHR has a articulate advantage. Knowledge of which females were exposed for convenance and which ones resulted in a successful pregnancy are critical to compute a reliable EPD.
Genomics
Another innovation that is helping to improve the accuracy of reproduction EPDs is the use of genomics information in genetic evaluations (encounter fact canvass 2014-12). Genomics, in combination with expert records, provides the opportunity to become relatively authentic EPDs on a balderdash at a young historic period. With records lonely the process is much slower considering of the long generation interval in beef production. For a trait such as stayability there are no records on a bull until he is approximately 8 years erstwhile (vi-yr old daughters); therefore, the information that determines a bull'due south EPD is typically based on pedigree data instead of his own data. Genomics can provide individual information on the bull at an earlier age.
Genetic by Ecology Interactions
Matching genetics to the environment and direction is critical to ensure good reproductive performance. In beefiness operations that accept limited or low quality diet, and combine that with genetics for high productivity, increase their adventure for reproductive failure. Cattle that have genetics for high growth and milking ability have high maintenance requirements, every bit well as, require high levels of nutrients to see that level of productivity. This combination, in absence of the required nutrients, results in reduced body condition which adversely affects their power to cycle and breed.
Summary
Maintaining high reproduction rates is an important factor in beef producers being assisting. Although providing a good environs for cattle is essential to reproductive success, there are also genetic practices that tin can be implemented to improve the likelihood of acceptable reproduction. For commercial producers it is important to implement a good crossbreeding programme to provide the all-time opportunity for high reproduction rates. Selection, through the employ of EPDs will provide limited, just valuable improvements to diverse reproduction traits that can be utilized in both seedstock and commercial beef operations. EPDs can also be used to help match genetic potential of the herd to the diet level of the surround. Combining skilful direction with sound genetic practices gives producers the best opportunity for high reproductive performance.
*Click here for printable pdf version.
Source: https://beef-cattle.extension.org/genetic-practices-to-improve-beef-cattle-reproduction/
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