WORKSHOP ON BULL PERFORMANCE TESTING HELD AT K.A.R.I (KENYA AGRICULTURAL RESEARCH INSTITUTE) - BEEF RESEARCH CENTRE
15th January 2001
Sponsors: The Boran Cattle Breeders Society and Agricultural Research Fund
Authority: Prepared by the Project Principal
Investigator - Douglas Indetie
Project History: -
The project began with proposal submission to the Agricultural Research Fund in December 1996, and received funding from World Bank, in 1998 under the KARI-NARP II assistance.
The initial phase involved two-day stakeholders workshop to determine the project activities and sampling sites. The next activity involved construction of bull handling facilities and rehabilitation of vehicles used in the fieldwork.
A critical part of the work plan involved contacts and discussions on participation of collaborators in the project. These were the Central Artificial Insemination Station (CAIS) who were to collaborate in semen sampling; the University of Nairobi, department of Animal Physiology Reproductive Biology Unit who were to collaborate in sampling of blood for hormone level determination, and the Department of Animal Science who were to collaborate in data analysis of phenotypic data collected on the bulls. Lastly farmers, who were to provide the bulls to be tested at the Centre.
Bulls to be tested were purchased or loaned to the Centre in November and December 1999 and were allowed to acclimatise to this environment at the centre up to March 2000 when blood and semen sampling began. Body measurements were taken beginning December to date.
The bulls have been dipped weekly since arriving at the Centre, de-wormed thrice and vaccinated once against FMD, Rinderpest and Anthrax. The bulls were grazed on ley pastures of Rhodes grass in paddocks for 24 hours. Water and salt provided ad libitum.
Project Introduction: -
Indigenous cattle are well adapted to tropical conditions and have a high degree of tolerance to adverse environmental and disease situations.
There is potential for improvement of beef and meat production, if the right breeding objectives and selection criteria are established. A critical aspect of improvement is the use of evaluated and proven sires in beef herds. The use of central performance tested bulls from various herds offers a co-ordinated approach of evaluating bulls, which can be used as future sires to improve productivity.
The value of such bulls can then be priced depending on the evaluation outcome compared to their contemporaries. During performance testing, reproductive potential can be assessed by determining semen characteristics and hormone profiles that support this potential.
General Objectives: -
Through central performance testing, to select bulls of proven productive and reproductive performance for use as sires in selected beef herds. Progeny from these sires will also be evaluated to validate the findings of performance testing.
Project Work plan and Activities ;
- Bulls were selected from Kajiado, Laikipia, Baringo and Nakuru district.
- Three Zebu breeds were involved and included the Boran, Sahiwal and the E. African Zebu* Bulls were “backgrounded” for 3 months before beginning tests to allow for acclimatisation to Lanet conditions.
- A total of 15 Boran bulls were obtained from ; Soysambu, Delamere Estates Ltd; Mutara Ranch; Mogwooni Ltd; Beef Research Centre, Lanet; and Ol Pejeta Ranching Ltd.
- Seven Sahiwals were also obtained from KARI-NAHRC- Naivasha and KARI-Regional Research Centre – Perkerra.
- Thirteen E. African Zebus were obtained from eight pastoralists from Kajiado and Baringo districts.
- There were a total of 35 bulls at the beginning of the project whose age ranged from 19 - 26 months.
- On arrival, the bulls were vaccinated against FMD, rinderpest, anthrax and CBPP. They have also been dipped weekly and de-wormed 3 times amongst other routine health activities.
- Preputial sheath washing were taken from all the bulls individually to test for Trichomonas foetus and vibriosis which are sexually transmitted in cattle.
For the test period the bulls have had the following data collected: -
a). Physical Parameters (linear measurement) sampled bi-weekly
- Live weight - access growth during the test period
- Heart girth measurement - determines morphological changes.
- Scrotal circumference, length and height - access changes in scrotal size.
- Testis - determine firmness and resilience.
b). Semen characteristics sampled monthly
- Semen volume, density, concentration, mortality.
- Semen morphology (sperm heads and tails and cytoplasmic droplets).
- Live dead spermatozoa ratios
c). Blood sampling, once a month
- Lutenizing hormones (release of testosterone by the leydig cells)
- Cortisol levels (released during stress and shuts of the reproductive system)
- Testosterone (influences spermatogenesis and male sexual behaviour)
- Prolactin (influences development of secondary sex glands)
- Packed cell volume ratios (gives an indication of the health status of the animal)
Determination of these parameters and their relationship can be used to determine the growth potential of a bulls progeny and its serving capacity which directly influences productivity and therefore profitability in a beef enterprise.
The bulls have therefore been compared within breed and between breeds and will be returned to their herds of origin for breeding to validate these results based on their progenies performance.
Project Benefits: -
An understanding of the various parameters that determine growth and reproduction will lead to the development of simplified and accurate methods of selecting breeding bulls. The relationships and interactions between these parameters will result in efficient ranking of the bulls whose performance should be replicated in the field.
Various linkages have been developed between stakeholders in the beef industry with an aim of sensitising the beef cattle producers to carry out performance testing of bulls before thy are introduced into the breeding herds.
A critical criterion on the evaluation of bulls will be established and should be sustained with financing from the farmers themselves.
Comparisons of bulls between breeds and herds is possible with information from performance testing, therefore determining the price levels of various bull based on their performance results.
Central staff have been exposed to modern techniques of hormone determination using Radio-Immuno-Assay (RIA).
Final results still under publication.