Retrospective analysis of selected artificial insemination (AI) related practices, maternal factors and success rate of AI in water buffaloes in three rural areas in the Philippines (1998-2015)

Adrian P Ybañez^1,2, Rochelle Haidee D Ybañez¹, Alexandra Jane G Fojas¹, Pamela Laida T Malate¹, Julius V Abela³, Edgar S Nuñez³, Johnson T Royo Jr³ and Ivy Fe M Lopez³

¹ Biology and Environmental Science, College of Science, University of the Philippines Cebu, Lahug, Cebu City 6000, Philippines
dr.adrianpybanez@gmail.com
² Gullas College of Medicine, University of the Visayas, Banilad, Mandaue City 6014, Cebu, Philippines
³ Philipine Carabao Center at Visayas State University, Visca, Baybay City 6521-A, Leyte, Philippines

Abstract

Artificial Insemination (AI) is a reproductive technology applied in Philippine water buffaloes (Bubalus bubalis). The success of AI can be dependent on several factors. The study aimed to retrospectively analyze data on selected artificial insemination practices, semen source and maternal factors on its influence on the success rate of AI in the rural Eastern Visayas (Leyte, Samar, and Biliran), Philippines from 1998-2015. A total of 34,833 AI cases from the database and written record sheets from the Philippine Carabao Center at Visayas State University were analyzed. Maternal factors included age, breed, type of heat, body score, body temperature, number of previous calves, and estrus signs. Further data processing and statistical analysis were performed at the University of the Philippines Cebu, Lahug, Cebu City. Results showed that the semen used was frozen, and two straws were mostly used in each conduct. The majority of the semen deposition was at the body of the uterus. The highest recorded number of inseminations was in 2013 and lowest in 2002, while the highest success rate was in 2001-2003 with Samar having the highest efficiency. Statistical analysis revealed significant associations of AI success rate with semen source (P<0.001) and with selected maternal factors, including breed (P<0.001), type of heat (P<0.001), body score (P<0.001) and mucus discharge (P=0.001). Moreover, the semen source was also found to be significantly correlated with the resulting sex of calves (P=0.003). While several parameters were found to influence AI and its success rate, technicians must still take into consideration all other factors considered vital for a successful AI.

Keywords: Bubalus bubalis, Eastern Visayas

Introduction

Artificial insemination (AI) involves the manual placement of semen in the female reproductive tract. Its advantages include the prevention of the spread of infectious heritable diseases and the breeding between animals in different locations (Kaaya et al 2005; Morrell 2011). Several countries have used AI to improve its livestock (Bane and Hultnas 1974). The widespread and harmless use of AI with preserved bull semen has provided opportunities to developing countries for genetic growth, without depending on breeding companies (Martinez 2012).

In the Philippines, the use of AI is advantageous because it is an archipelago, which makes natural breeding impractical for animals that are distantly situated. Through AI, several animals can benefit from the genes of superior males (Morrell 2011). AI has been used in the Philippine water buffalo production. Bubalus bubalis, locally known as “carabao”, is widely used in the Philippines over cattle because of its multi-purpose use for draft, milk, and meat (Vale 2004). As water buffaloes can be poor breeders due to low fertility (Drost 2007), late maturity, poor estrus expression and detection, prolonged calving intervals, and seasonal reproductive patterns (Bhattacharya 1974), improving reproduction using AI is imperative.

While AI can impact the water buffalo production in the country, published studies have been limited. Several areas in the country are agricultural provinces, including Leyte, Samar, and Biliran, with many smallholder farmers who usually own swamp type buffaloes (Borghese and Mazzi 2005; Perera 2010). The Philippine Carabao Center (PCC) at the Visayas State University (VSU) have kept AI related records that can be useful in giving insights to improve operations and performance of AI. To analyze these previous records, a retrospective analysis will be useful.

Methodology

Research design and study area

The study utilized a retrospective descriptive-analytical design. It was conducted at the Philippine Carabao Center (PCC) in VSU, Baybay City, Leyte and at the University of the Philippines Cebu, Gorordo Ave., Lahug, Cebu City. AI related records, including selected AI practices, semen source, and maternal information, from selected areas in Eastern Visayas (Leyte, Southern Leyte, Biliran, Western Samar, Northern Samar) from 1998 to 2015 were screened.

Data gathering, processing, and analysis

A letter was sent to PCC in VSU requesting permission to access their AI-related records. After approval, records were obtained, which were either from the encoded database or written data sheets. In this study, the success rate was interpreted as the number of calf drops divided by the number of recorded insemination (NRI) per area. The gathered data were manually tabulated with assigned codes and encoded in Microsoft Excel Office. Assigned codes accounted for the different variables for statistical analyses. Coded data were analyzed using descriptive statistics. Linear regression and one-way analysis of variance were applied where applicable.

Results and discussion

A total of 34,833 records were gathered from 1998-2015. The operation year with the most AI services recorded was in 2013 (4857 services or 13.94% of the records) when PCC in VSU was doubling its efforts to increase the water buffalo population to recover losses from the typhoon Haiyan. On the other hand, the lowest number of records was in 2002 (7 or 0.02%), which all occurred in Leyte. This low number of record was reportedly due to the series of mild earthquakes that centered Samar area and that the focus of Region VIII that time was in crop production (Personal communication).

Profile of AI related practices and maternal factors

Records revealed that the semen type used in all AI services was frozen, which was mostly inseminated using two straws (93.4%) at the body of the uterus (51.9%) (Table 1). A total of 104 bull semen sources were also recorded. The frozen semen ensures effective use through dilution and appropriate dosage to many females, utilizing semen of sires with superior genotype and increasing the rate of conception by proper estrus detection, good reproductive management and medication (Ranjan and Pathak 1993). PCC at the National Headquarters and Gene Pool distribute frozen semen of genetically superior sires from the Semen Processing Laboratory in Caranggalan, Nueva Ecija and Los Baños, Laguna, Philippines. Although fresh or chilled semen may result in higher conception rate (Cruz 2000; Saacke et al 1980), use of these types appears impractical due to limitations in the facility, expertise, source availability and distances between animals for breeding. On the other hand, the use of 2 straws (as reported in this study) is also recommended. As each straw contains five mL of semen (with approximately 50 million sperms), deposition of 10 ml from 2 straws of semen is enough to fill up the intrauterine cavity and ensure its administration through the interstitial part of the tubes and ampulla (Mamas 2006). In a natural environment, a single ejaculate of a buffalo bull contains 700-1600 million spermatozoa per ml (Kushawa et al 1955), which could already impregnate 300 to 1000 females.

Most inseminated female buffaloes were aged 6-10 years (47.4%) or 5 years and below (44.5%), of native breed (79.3%), with 1 or no previous calving (54.8%), and with a body condition of 3 or 4 (77.1%). During insemination, the majority of the estrus were natural (63.2%), with an average body temperature of 38⁰C (51.7%). Commonly observed heat signs were sticky vulva (69.3%), hard cervix (51.4%), slightly hard uterus (58.1%), reddish vagina (58.1%) and clear (38%) or cloudy (38.4%) mucus discharge (Table 1). The most frequently reported age group (6-10 years old) in this study is known to be ideal for AI (Momongan et al 1992; Botchan et al 2001). Animals above this age group may have decreased fertility due to progressive follicular depletion, decline in granulosa function and poor oocyte quality (Hughes et al 1990; Navot et al 1991), and reduced endometrial receptivity (Yaron et al 1993) as consequences of aging.

In terms of breed, the Philippine native carabao was the most frequently used female buffalo in AI cases. Their high frequency may be because they dominate the local buffalo populations and are usually preferred due to their docile temperament and endurance for work (Bondoc 1998). They are also used to mate with river buffaloes to produce crossbreeds with the strength of a swamp buffalo and the milk-yield of river buffaloes. A moderate body condition score of 3 was observed most frequently among the inseminated buffaloes, which may result in high conception rates (Vale 2004; Nam 2010). Probably due to the costs in using hormones for estrus synchronization, estrus was mainly natural. On the other hand, the observation of sticky vulva as one of estrus signs was similar to a previous study (Singh et al 2000), in which sticky mucus was seen as strands hanging out the vulva. More similar observations from the same study were hard cervix, slightly hard uterus, and reddish vagina. A marked uterus tone is believed to result in high conception rates. Another observation in this study was the cloudy mucus discharge, which may indicate the presence of pathogenic bacteria (Sheldon et al 2009). AI technicians must consider treatment to these animals.

AI success rates

Reported AI success rates per area from 1998 to 2015, were found to vary. Samar was found highest (9.8%) with 3337 reported AI services producing 326 calves. It was followed by Leyte (9.1%) and Southern Leyte (8.9%), with Eastern Samar (0.5%) having the least (Figure 1). The difference in success rates between regions may be affected by the geographical terrain (Vale 2007), nutrient availability (Singh et al 2000, Dominguez, 1995, Anzar et al 2003), fertility of semen used in that region, and the AI practices employed in the area (Anzar et al 2003). On the other hand, the high success rate of Samar may be accounted for the easy access on the frozen semen from 3 artificial breeding centers in Gandara, Sta. Rita and Catbalogan. Similarly, Leyte, which has the highest percentage of available land area for raising livestock among the provinces according to Department of Agriculture in 2004, is where PCC in VSU is strategically located, providing easy access to semen and regular monitoring. Meanwhile, the low performance of Eastern Samar could be due to unavailability of breeding centers nearby and the characteristic topography of the area (mainly forest land). As reported during the UNAIP 2012 Year-end Assessment and Planning Workshop in Maasin, Southern Leyte, issues that highlighted the entire region’s low AI success rate were inadequate supply of frozen semen, untimely submission of reports, lack of program promotion and advocacy at the regional/provincial levels, and lack of AI paraphernalia (Personal communication).

Figure 1. AI success rates per region in Eastern Visayas from 2001 to 2015

On the other hand, AI success rates have differed through the years (Figure 2). Although it appeared to be highest in the years 2001 to 2003, only very few AI services were conducted (2001=663, 2002=7, 2003=87). However, it is also possible that there many AI services that were not properly recorded. Although Samar already started contributing AI services the following year, a drastic drop still followed in 2004, AI in the area may have been performed by amateur technicians lacking in training. Although there was an increase in the conduct of AI services due to increase in the number of technicians, recording of calf-drops may not have been well reported. Other sharp decreases in success rates were found in 2006 and 2008. These reductions maybe affected by the damages caused by typhoons Reming and Frank in 2006 and 2008 respectively. Both typhoons are included in the top deadliest cyclones that hit the Philippines. Another low success rates in 2012 and 2013 may have also been due to the respective typhoons Pablo and Yolanda. The varying success rates per area and year show how AI success can be affected by meteorological factors. Other factors that may also have an effect include ambient temperature, humidity, solar radiation, and rainfall (Gomes Da Silva 2006).

Figure 2. AI Success Rates from 2001 - 2015 in Eastern Visayas

Statistical analyses

From the several AI related practices and maternal factors, only the bull source of semen was found to be highly correlated with the resulting sex of calves (df=34, X2=61.2, P value=0.003) (Table not shown). Results imply that the semen source should be well monitored and that some sources would have higher probabilities of producing a particular sex (Lu et al 2010) have suggested the sexing of sperms in AI to accelerate genetic improvement of buffaloes.

Breed, location, type of heat, and bull source of semen (Table 2) were found to be highly correlated with the success rate of AI. Hence, the following factors must be considered in the performance of AI and the expected results. Some locations may not be favorable because of varying environmental conditions (Gomes Da Silva, 2006). Areas with higher environmental temperature can cause a decline in the reproductive activity due to heat stress (Putney et al 1989). Buffaloes undergoing insemination when exposed to a temperature above 26ºC would have high respiration rate and rectal temperature, thus, resulting in an impaired metabolism, reproductive performance (Kadzere et al 2002) and lower quality of oocytes (Roth et al 2001). Moreover, each area has different technicians, who also have varying skills and performances (Singh and Singh 1989). Meanwhile, animals with natural heat also appear to have a better performance than those artificially synchronized. This is contrary to a previous finding where the use of natural heat has been found to result in lower fertility and conception rate as compared to AI cases using synchronized heat (Moioli et al 1998; Perry, 2005). It is probable that technicians may have lacked the expertise to detect properly or monitor estrus during synchronization as external signs of heat are reportedly more difficult to detect than in natural estrus (Barile 2012).

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Received 22 September 2016; Accepted 11 January 2017; Published 1 April 2017

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