REPEATABILITY ESTIMATION OF SEMEN PRODUCTION AND QUALITY OF LOCALS MADURA CATTLE BREED ( Bos indicus )

The objective of this study was to evaluate the effect of genetic and environmental factor on locals Madura catt le semen production and quality. A total of 2275 semen collections records from 11 bulls from 2012 to 2014 were analyzed to evaluate the genetic potency of semen productions. Genetic evaluation consists of repeatability estimation of semen volume, sperm concentration and sperm individual motility. Data were analyzed by HGLM (REML) with environmental factors of age, seasons, interval of semen collections, and frequency of ejaculations as fixed effect and bulls as random effect using GENSTAT 16 edition. Result showed that age and ejaculation frequency affect to all variables; interval of semen collections affected to both semen volume and sperm concentrations; while seasons only affected to sperm concentrations. Repeatability estimation of semen volume, sperm concentration and sperm individual motility were 0.376, 0.445 and 0.567 respectively. It was concluded that the quality of Madura bulls ejaculate less affected by environmental factors. ____________________________________________________________________________________________________________________


INTRODUCTION
Madura cattle are one of local Indonesian cattle that has important role in social and cultural life for Madura tribe.Unfortunately, since artificial insemination using Limousin breed being allowed in Madura Island in 2001, the interest of local breeder to breed Madura cattle decreased (Widi et al., 2013).Despite having high economic value, limitation of natural breeding system become a hindrance for the spread and affordable distribution of high quality seeds of Madura cattle (Kutsiyah, 2012).The better Production performance and higher economic value of crossbreeds meats as compared to local Madura cattle, was another reason for this shift of interest (Nurgiartiningsih, 2010).
East Java Provincial Government with Singosari National Artificial Insemination Centre (BBIB), attempted to return the interest of local breeder to breed Madura cattle and maintain its population in Madura Island by selection of superior and favourable bulls of Madura cattle, to produce frozen semen, and distributed it through an artificial insemination program.Since the agreement with local governmental in 2010, the demand of frozen semen of Madura cattle increased drastically, so the number of Madura bulls should be increased to meet the demands.
Increasing bulls population was not always an effective solution to meet the demands of frozen semen production.Previous study showed that to maintain production of good quality frozen semen, bulls reproduction characteristic in the environment of frozen semen production needs to be characterized, because the bulls libido and ejaculate characteristic fluctuated in every collection period (Al-Badry, 2013).Important reproduction parameters to determine the quality and quantity of ejaculate in frozen semen product are semen volume, spermatozoa concentration, and individual motility of spermatozoa per ejaculate (Karoui et al., 2011).Genetic factor and some environmental factors such as age, weather, and semen collecting management were known to affect the quality and quantity of ejaculate (Mathevon et al., 1998;Brito et al., 2002;Fuerst-Waltl et al., 2006;Bhakat et al., 2011).Madura cattle's frozen semen producer need to understand how genetic and environmental factor influence reproduction parameters of bulls and its consistency in every production period, to achieve efficient production of frozen semen.This study estimated the reproduction consistency in every production period using parameters, such as; semen volume, spermatozoa concentration, and individual motility of spermatozoa as an evaluation to manage future frozen semen production of Madura cattle.

Material
Data in this study was 2,275 records of Madura bulls semen collection from January 2012 until December 2014 in BBIB Singosari located in Malang,East Java (7° 50'14.6 "S 112° 38'43.7 "E).The data was recorded from 11 bulls aged 3-7 years old.All bulls were caged individually and received the similar daily ration and care management.

Collection Process and Semen Evaluation
BBIB Singosari collected semen from Madura cattle bulls twice a week, with an interval of four to five days.Each acquired 1-2 ejaculation with an interval of 15 minutes between each ejaculation.We obtained data of semen volume by reading the scale on collector tube inside the artificial vagina.Semen concentration was obtained by examine a mixture of 35 µl semen and 3.5 mL NaCl 0.9% of using minitube® Photometer SDM6.Spermatozoa individual motility was evaluated microscopically with 200x magnification of 0.1 µl semen inside 0.1 µl diluents at 37-38° C which set up using minitube® slide warmer.All the collection and evaluation process were carried out under ISO 17025:2005 management.

Data Analysis
The estimation of repeatability value was evaluated on semen volume, spermatozoa concentration, and individual motility which were considered as variate response; with bulls as a random effect representing genetic factor, and fixed effect representing environment factor such as: age (5 category : 30-42 months, 43-54 months, 55-68 months, 69-80 months, and 81-92 months), seasons (4 season: January-March, April-June, July-September, and October-December), collection interval (2 intervals, 3 and 4 days), and ejaculation frequency (2 frequency, ejaculation I and II).

Environment Factor
Analysis using HGLM showed that age and ejaculation frequency affected all variable; while collection interval affected semen volume and spermatozoa concentration; and season only affected spermatozoa concentration (Table 2.).This result corresponded with previous study reported on Bos taurus (Mathevon et al., 1998;Fuerts-Waltl et al., 2006;Karoui et al., 2011) and Bos indicus (Brito et al., 2002;Ahmad et al., 2011).The effect of age on semen volume, spermatozoa concentration, and individual motility was due to the testis growth and maturity followed the bulls aged (Brito et al., 2002;Torres-Junior and Henry, 2005;Moura et al., 2011).The difference in semen quality related to season could be explained by the difference temperature in the environment, photoperiod, humidity, availability of feed, and housing condition (Mathevon et al., 1998;Bhakat et al, 2011); meanwhile, collection interval and ejaculation frequency affected semen due to daily production of spermatozoa, spermatozoa viability inside epididymis, and epididymis capacity (Jones, 1999;Jones, 2004).

Semen Production Repeatability
The estimation of repeatability value of semen volume, concentration, and individual motility of spermatozoa were carried out using fixed effect (age, season, interval of semen collection, and ejaculation frequency per gathering) and random effect (bulls).Estimated repeatability for semen volume, concentration, and individual motility of spermatozoa were 0.375, 0.445, and 0.576, respectively (Table 3).
Semen volume, concentration, and individual motility of spermatozoa of Madura cattle in this study considered as moderate-high category.Based on repeatability value, the value of 37.5%, 44.5%, and 57.6% variability of semen volume, concentration, and individual motility of spermatozoa, respectively, were caused by genetic diversity of bulls in Madura cattle.This result was similar to the study reported on Bos taurus in temperate climate (Taylor and Everett, 1985;Mathevon et al., 1998;Boujenane and Boussaq, 2013).
Bulls adaptability to environment was one of individual genetic factor that have an important role in semen production.Haque et al. (2001) reported repeatability value of semen production on Bos taurus that lived in tropical environment was lower than the one that lived in temperate environment.Better repeatability value was found in crossbred between Bos taurus with local cattle that have better adaptability in tropical environment.
Madura cattle is local cattle that have better adaptability in tropical environment, better tolerance in low quality feed, and better reproduction appearance than Ongole crossbred and Bali cattle (Wijono and Setiadi, 2004).Repeatability value on semen volume, spermatozoa concentration, and individual motility of spermatozoa in Madura bulls was categorized as moderate-high in this study, and it could be due to good adaptability in natural environment in tropical environment that was supported by improvement in maintenance management.

CONCLUSION
This study showed that Madura cattle have moderatehigh repeatability value on the following reproduction parameters: semen volume, spermatozoa concentration, and individual motility of spermatozoa.Genetic factor played a greater role than environment factor in variability of semen production between Madura cattle.

Table 1 .
Data of semen volume, spermatozoa concentration, and individual motility of spermatozoa on Madura bulls in BBIB Singosari from 2012-2014

Table 2 .
Effect of permanent environment factor (fixed effect) on semen volume, spermatozoa concentration, and individual spermatozoa motility in Madura bulls using Wald test