Malaysia is one of the countries that increasing the production of livestock industry in Asean region. The productions of livestock animals such as cattle, sheep, goat, buffalo, poultry and swine are increasing every year to support the increasing level of self-sufficient. Research done by Department of Veterinary Services on livestock population found that the numbers of livestock in 2008 are 3,277,158 and from that amount, swine is the highest population with 1,733,466 animals (DVS, 2010). However, statistics present by Department Of Statistics Malaysia on the livestock sub-sector based on the Annual Census of Agricultural Establishments that was conducted in 2009 for reference year 2008 shown that the poultry farming contributed the largest percentage in the livestock industry with 53.0 %, followed by pig farming 21.5 %, cattle farming 18.4 % and other livestock farming 7.1 %. Although the productions of animal livestock are increasing, it still not enough for self-sufficient especially for cattle, sheep and goat (DOS, 2009).
GOAT PRODUCTION IN MALAYSIA.
In goat production, populations of goats in Malaysia are still low compared to other animal production. In 2004, the goat populations in Malaysia are only 264,394 and increase to 437,805 in 2008 (DVS, 2010). However, this amounts still not enough to support self-sufficient not only mutton, but also for milk. Thus, government wants to increase the production of goats to 25% by 2010.
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There are many efforts taken by government in order to achieve the target to increase the goat production in Malaysia from improve the husbandry practice, nutrition (Vidyadaran, 1988), government policies, help to increase smallholder farmers and use new technologies. One of the new technologies that were introduced to increase the production of goats was by using oestrus synchronisation.
PROBLEM IN OESTRUS SYNCHRONISATION.
Usually, the farmers in Malaysia are depends on natural oestrus cycle in order to breed theirs animals. Thus, the productions of goats are still at the same level and cannot increase. The effective way is by using oestrus synchronization. However, in order to apply these new technologies in Malaysia, there was lack of information of the effect and the protocol of oetrus synchronisation in goats. So the research on the effect of two protocol oestrus synchronisation protocol will give the farmers information about the effective oestrus synchronisation protocol and help to increase the population of goats in Malaysia.
OBJECTIVES OF STUDY.
The aim of this experiment was to investigate the effect of two protocol using CIDR (Controlled Internal Drug Release) on oestrus synchronisation in Boer goats by measure the number of animal comes to oestrus, to determine the time of animals show oestrus sign, and to evaluate hormonal level (progesterone) before and after synchronisation between two synchronisation protocols. All the results will give the appropriate oestrus synchronization protocol that suitable and economical to applied by farmer in Malaysia.
CIDR treatment for 14 days with conjugate of 400 IU PMSG and 0.05 mg cloprostenol give better result in oestrus synchronization compare to CIDR treatment for 9 days with conjugate of 0.05 mg cloprostenol.
WHAT IS OESTRUS SYNCHRONISATION?
Oestrus synchronization is a management practice that used to induces heat and ovulation in a group of animal in a farm at the same time. This practice can be applied to farm animal such as cow (Deutscher, 2010; Patterson et. al, 2003; Mapletoft et. al, 2003), deer (Eveline et.al, 2009), sheep and goat (Wildeus, 1999; Freitas, 1996; Alacam et. al, 1984).
This practice is mainly focused to manipulate the luteal or follicular phase of the oestrous cycle (Wildeus, 1999; Patterson, 2003), control oestrus and ovulation in cycling females and breeding can be conducted within short period (Deutscher, 2010).
HISTORY OF OESTRUS SYNCHRONISATION
The histories of oestrus synchronisation start long time ago. This approved through the studies on induction of the oestrus using male effect (Lamont, 1964; Shelton, 1960), and using the hormone such as progesterone, pregnant mare serum gonadotrophin and sex controlling hormones (Marincowitz, 1968; Marincowitz, 1967; Corner and Allen, 1929). However, there are more studies and publication on the oestrus synchronization in past 30 years. The developments in the studies change the technique of oestrus synchronization from traditional protocol into the modern protocol that gives more effective result. The modern protocols of oestrus synchronization were developed since 1960's which the introduction of intravaginal steroid devices in sheeps and in cattle in 1970 (Gordon, 2004).
ADVANTAGES OF OESTRUS SYNCHRONISATION
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There are many advantages from using oestrus synchronization techniques to induced oestrus. Oestrus synchronization allowed the farmer to breed a group of animal by greater use of superior sire through artificial insemination or natural mating at the same time. Thus, this can improve the management especially in reproduction management practice and record keeping in a farm such as better allocate and plant marketing strategies. It saves time and labour in detecting oestrus (Gordon, 2004).
Besides that, oestrus synchronization can reduce the animal reproduction problems such as abortion, increase the percentages of animal exhibiting oestrus, improved fertility and ovulation. Oestrus synchronization also allows more uniform groups of young, which can be reared to market weight more easily than those born in uncontrolled births with good growth rate and high weaning weight. Another advantage of oestrus synchronization is it can be use for superovulation in embryo transfer process (Gordon, 2004).
TECHNIQUES OF OESTRUS SYNCHRONISATION.
There are many methods can be use to induce oestrus. Oestrus can be induced using varying techniques included alteration of light patterns technique, manipulation of social inputs such as exposure to buck, hormonal treatments or the combination of two or more techniques.
All the methods have different response to the animal's oestrus cycle. Light treatments that use to alter photoperiod response and stimulate the oestrus on animal are well-known method in the dairy goat industry (Whitley and Jackson, 2004). This treatment can be replaced by using the melatonin that also can alter photoperiod response in the animal. Research by Wuliji et al. (2003) founded that the administration of melatonin for oestrus synchronization give better result on pregnancy in goat compared to light exposure method. However, the response of light exposure method can be increase by combine both light and melatonin method.
Another method in oestrus synchronization is by manipulated the social output such as buck or male exposure (Kusina et al., 2000; Ishwar and Pandey, 1992, Chemineau, 1987)). This method was done by exposed female to the male after a period of isolation. The presence of male animal can trigger the hormonal changes and stimulate the oestrus in female animal. The exposure to male effect is mediated through changes in pulsatile GnRH release from the hypothalamus, selectively increasing of Luteinizing Hormone (LH) (Wildeus, 1999). The response of male effect on oestrus cycle are depend by such factors included the body condition of male (Walkden-Brown et al., 1993a), the serving capacity and sexual aggressiveness of male (Walkden-Brown et al.,1993b; Perkins and Fitzgerald, 1994) and the different between contact type of male to female animal which are immediate, fence-line or intermittent (Walkden-Brown et al.,1993c).
However, the hormonal treatments seem to be more efficient to induce estrous in female animal especially in minor animal like goat and sheep. Examples of hormonal treatments included melatonin, progestogens (either administered orally, injection or by intravaginal releasing devices), gonadothropins hormones and prostaglandins (PGF) alone or in combination (Whitley and Jackson, 2004).
Gonadothrophins hormone and prostaglandins can be use as the main treatment (Iswar et al.,1992; Alacam et al., 1985) or as co-treatment (Uslu, 2009; Dogan, 2008). Gonadothropins hormone are included the Gonadothropins Releasing Hormone (GnRH), Pregnant Mare Serum Gonadothropin (PMSG), Human Chorionic Gonadothropin (hCG) and Equine Chorionic Gonadothropin (eCG). The example of prostaglandin is cloprostenol.
The gonadothropin and prostaglandin treatment are control the oestrus cycle by terminating the luteal phase through regression of the corpus luteal (Wildeus, 1999). Study by Nuti et al. (1992) for the effect of cloprostenol injection on estrous response, timing to oestrus and the LH surge in dairy goats shown there were no different response when 125 µg cloprostenol was injected on d 6 and d 12. The animals show behavioral estrus within 46 to 48 hour mean time from injection with 95-100% of does responding.
The efficacy of the gonadothropin hormone and prostaglandin are different between as the main treatment and co-treatment. This is proved with study by Patterson et al. (1995) on the effect of prostaglandin alone and MGA intravaginal sponge to oestrus response, synchronized conception, pregnancy rate and fecundity in the postpartum cow. The results shown that the MGA-PG give higher result compare to PG alone.
Progestogens can be classified as a group of hormones. Progestogens also called progestagens or progestin. Progestogens is a part of the five major classes of steroid hormones which are also contain estrogens, androgens, mineralocorticoids, glucocorticoids (Wikipedia, 2010). One of the characteristic of progestogens is they have basic 21 carbon skeleton called a pregnane skeleton (C21). All steroids with a pregnane skeleton, that is, both naturally occurring and synthetic ones, exogenous or synthetic hormones are included as the progestogen class of hormones. The example of progestogens hormone is progesterone (P4).
Progestogens get its name for their function in maintaining pregnancy (pro gestational). Progestogens are also present at other phases of the oestrous and menstrual cycles. Beside, the other functions of progestogens including control birth process, antiandrogen, and control Cachexia Syndrome. Due to the functions of progestogens mainly in control menstrual and estrous cycle, progestogens are used as a method to induced oestrus.
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There are many types of progestogen formulated to induce oestrus in goats. One of that is norgestomet which available for use in goats and sheep (Wildeus, 1999; Mellado et al., 1998). This progestogen product was marketed under the name SyncroMate-B (SMB). The effect of norgestomet will be more effective (100% in oestrus within 9 days) when gonadotrophin co-treatment were use at removal (Oliveira et al., 2001). Norgestomet also can be found in ear implant form.
At recent years, where the manufactured of norgestomet product are no longer, the new products of progestogen were introduced to induced oestrus. The progestogen sponge containing fluorogestone acetate (FGA) and methyl acetoxy progesterone (MGA) take placed as the alternative to norgestomet to increase the response of progestogen in induced the oestrus. The sponge is intravaginal devices that usually inserted over period 9 to 19 days (Wildeus, 1999) and will release the progesterone in the vaginal during insertion period. In the early application of intravaginal devices to induce oestrus, the treatment periods are longer within 14 to 19. In general, the longer the progestin was administered to animal, the higher rate of estrous synchronization, but the lower the fertility of the synchronized animals However, studies found that too long of administrated of progestogen treatment will result low fertility (Diskin et al., 2002; Vinoles et al., 2001). Hence, more studies were done to compare the respond of the progestogen treatment period and came out with the result that the shorter progestogen treatment can improved the fertility (Fonseca, 2004).
There are differences response of oestrus when intravaginal sponges were applied because depend on species, breed, co-treatment, management and mating system (Wildeus, 1999).
Many studies were done to compare the effective of intravaginal sponge and norgestomet in induced the oestrus. One of the studies was done by Kusina et al. (2000) where compare the norgestomet ear implant with natural progesterone in Mashona does within 14 days treatment. The results were reported with 93 % and 83% bred within 21 days and 64% and 70% kidding for sponges and implant.
The intravaginal sponges come with different dosage of progestogens. For example, intravaginal sponges can contains 15, 30, 45 and 60 mg of MGA. However, study by Igleasias et al. (1997) on the effect of different doses of MGA found that there are no different in the percentage of does ovulating (96.8%) or in ovulation. Other study on the effect of different doses of progestogen was done by Freitas et al. (1996) by using two insertion of intravaginal FGA sponges on Day 1 and Day 7 or Day 9 of an 11 day-treatment period in Alpine and Saanen goats. The goats were received 400IU PMSG and 50µg of cloprostenol 48 hours before sponge removal. The result from the study shown that there were no differences in percentage of does exhibiting oestrus between does supplemented with one sponge and does supplemented with additional FGA sponges on Day 7 or Day 9. Other than MGA in intravaginal sponges form, it also can be in feed supplement that fed to the animal to induce the oestrus and improve the fertility.
Besides norgestomet and MGA and FGA, there is another progestogen product that can give more effective result on induction the oestrus. The product is Controlled Internal Drug Release (CIDR). The information about the CIDR will be discuss in the next topic.
CONTROLLED INTERNAL DRUG RELEASE (CIDR).
CIDR is a new method to induce oestrus in goats (Jonathan, 1993). It was use since early 1990's for induce oestrus in small ruminant. Controlled internal drug release (CIDR) is an intravaginal device that contains progesterone. Protocol for the use of CIDR devices are usually same to protocol for intravaginal sponges. It is T- shaped devices (DeJarnette, 2004; Darrel, 2004) that can be deliver the natural progesterone into the animal body during treatment. Other description is from Wheaton and Wildeus state that the CIDR as constructed of a progesterone-impregnated medical silicon elastomer molded over a nylon core.
CIDR come in T-shaped where the wing of the insert collapse to form a rod that can be inserted into the vaginal using an applicator with assistant of some gel (the gel use as the lubricant during CIDR insertion). Opposite of the wing, a tail is attached that facilitate removal of device in the end of treatment. A nylon spine act as backbone to the CIDR and covered with progesterone impregnated silicone that release a relatively constant dosage of progesterone during in vaginal (Darrel, 2004).
There are two types of CIDR that usually use in oestrus synchronization for small ruminant. CIDR-S and CIDR-G are two commonly applied that contain from 9% to 12 % (330 mg progesterone) of progesterone level (Wildeus, 1999; Wheaton, 1988). This progesterone level will decrease during the CIDR applied in the vaginal. It is more efficient in releasing the hormone contains in the devices into the animal body compare to vaginal sponge (Hamra et al, 1986).
CIDR were developed and introduced as the alternative to progestogen sponges in oestrus synchronization protocol. The usage of CIDR provided more advantages compared to the sponges. For example, the design of CIDR-S eliminated the accumulation of foul-smelling mucus that can see it discharged upon the removal of sponges. Besides, CIDR have the lower loss rates, produce higher percentage of animal come to oestrus, and a shorter duration to onset of oestrus after devices removal (Lynch, 1985). Otherwise, the using of intravaginal sponges either with conjunction of hormones to synchronize the oestrus cause discomfort to animal and may adhere to the vaginal wall causing problem when removal (Holtz, 2005). Thus, the using of CIDR is best alternative to intravaginal sponge.
In a study of the effect using the CIDR on the oestrus responses, the ewes that treated for 14 days with 9% progesterone CIDR-S and 60 mg MAP sponges during breeding season shown that the CIDR-S exhibited earlier and more compact of oestrus (Rhodes and Nathanielsz, 1988). The effectiveness of the CIDR in oestrus synchronization can be increase by using co-treatment administration. Study reported by Oliviera et al., (2001) shown that application of CIDR for nine days with combined treatment ( 100 IU of eCG and 0.05 mg of cloprostenol at removal give 100% of oestrus response within 24 hours in 20 does. Other study where 30 does treated with CIDR for 16 days with co treatment 300 IU of PMSG at CIDR removal give the same result which was 100% shown oestrus within 27.2±0.40.
Picture 1: CIDR and its applicator
Earlier, progesterone determination were use to evaluate serum progesterone concentrations in order to detect pregnancy in goats (Corteel et al., 1982, Bretzlaff 1981, Holdsworth et al., 1979, Murray et al., 1988 and Pennington et al., 1982). Usually, the detection was done 21-24 days after breeding. Radioimmunoassay (RIA) technique was used since 1970's to determined the serum progesterone concentrations (Yousefnajadian et al., 1972; Faure, 1975; Van der Westhuysen, 1979). A new method to measure progesterone concentration by Enzyme Linked Immunosorbent Assay (ELISA) was described by van de Wiel and Koops (1986) modiï¬ed by Moeller (1991).
MATERIALS AND METHODS
ANIMALS AND TREATMENTS
Experiment was conducted at Infoternak Farm, Sg Siput, Perak. Sixty female Boer goats were used in this experiment. The goats were fertile and healthy. The aged for all goats were chose ranging between one to two years olds. All does were at first kidding. The does were reared in the intensive system and receive grass, concentrate and access on water adlibitum. The does also were supplied with urea salt blocks.
Does were assigned randomly into two groups (n=30 per group). Each group was placed in four pens randomly. The mean animal body weights for both treatments are 37.81±1.48 for Treatment 1 and 40±1.30 for Treatment 2. Both groups were received one of two treatments as follow: (i) Treatment 1 (T1), where the does received CIDR for fourteen days. All does in Treatment 1 then received 400 IU of FOLLIGON® (FOLLIGON® is a complex glycoprotein obtained from serum gonadotrophin of pregnant mares) and 0.05 mg of Estrumate® (Estrumate® contain active constituent of 250 µg/mL cloprostenol as the sodium salt) a day (24 hours) before removal of CIDR (Day 8).; (ii) Treatment 2 (T2), where the does received CIDR for nine days and received 0.05 mg of Estrumate® prior to removal of CIDR (Day 14). The experiment was be done in same period where the CIDR for T2 was inserted on day four (D4) of T1 to get same time of CIDR removal for both treatments. The application of the treatments was shown in Diagram 1 below.
Injection of 0.5 mg Estrumate® n 400IU FOLLIGON
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 D
0 1 2 3 4 5 6 7 8 9 10 11 12 D
Injection of 0.5 mg Estrumate®
Diagram 1: Ministered Of Treatments and Blood Samplings
Blood samples were collected through jugular vein for four times during the experiment. The samples obtained before insertion of intravaginal devices (D0), prior to injection of Estrumate® or/and FOLLIGON (D13 for T1 and D8 for T2), at removal of devices (D14 for T1 and D9 for T2) and 48 hours after removal of intravaginal devices (D16 for T1 and D11 for T2). Blood samples were collected into plain vacutainer tube (5ml) and stored at room temperature for one hour before transfer into refrigerator for one night. After bloods undergo centrifugation at 3000 - 3500 rpm for 15 minutes, serum was transfer into eppendorf tube and store at -20 ° C in refrigerator for analysis of progesterone and estrogen in laboratory. Route of blood sampling was shown by Diagram 1 above and represented by shape ( )
Oestrus sign were observed at every 6 hours interval beginning from 24 hours removal of intravaginal device. Each observation was conducted for 30 minutes. In every session, the oestrus sign and time it occurred were recorded. First sign of oestrus was recorded when the does showed tail flagging. Others sign of oestrus were observed included sign of mounting, reddened vulva and standing to be mounted. The detection of oestrus was done after 66 hours of intravaginal removal.
Tail flagging sign is the sign when the tail of does erect and vigorous tail waving. In this experiment, tail flagging sign will be indicate as the first sign of oestrus. This situation can be seen when the animal start come to oestrus. Mounting can be defined as the situation where the doe mount to the other animals. Third sign which is standing to be mounted is when the animal assumes an immobile stance or stand still in response to pressure on its hindquarters due to other animal mount on it. Last sign is reddened vulva where the area of vulva to red.
Picture 2: Sign of oestrus (mounting and ready to be mounted)
Progesterone determination was done by using Enzyme-Linked Immunosorbent Assay (ELISA) technique (Radwanska et al., 1978; Al- Soboiyl, 2009). The progesterone enzyme immunoassay kit (Progesterone ELISA, IBL) that provides material for the determination of progesterone in serum and plasma was used in this analysis. For progesterone determination, only serum samples from blood taken before CIDR insertion and after 48 hours after CIDR removal of 48 selected animals were analysed.
Firstly, the frozen samples were thawed at room temperature using new disposable tips, 25 µl of standard and samples were dispensed into appropriate well. The kit then was incubated at room temperature for five minutes. After five minutes, 200 µl enzyme conjugate were dispensed into each well. All the samples undergo thoroughly mixed for 10 seconds before incubated for one hour at room temperature.
Contents of the well were briskly shake out after one hour before rinsed the well three times (400 µl per well for each time) with diluted wash solution (30 µl of wash solution was diluted with 1170 µl of distilled water). Then, the well was stroked sharply on absorbent paper to remove residual droplets.
Each well was added 200 µl of substrate solution and was incubate for 15 minutes at room temperature. The enzymatic reaction was stopped after 15 minutes by adding 100 µl stop solution into each well. Within 10 minutes, the samples were read the optical density at 400±10 nm with a microtiter plate reader.
SAS 9.0 EDU Edition was used to analyze all the data and result. Chi-square analysis was used to compare the number of animal come to oestrus. General Linear Model was used to analyze the mean time to onset of oestrus sign and differences of hormonal level.
PERCENTAGE ANIMAL COMES TO OESTRUS.
Table 4.1: The numbers of animals come to oestrus within 66 hours of observation.
Animals comes to oestrus (%)
The result of the numbers of animals come to oestrus show there is no significant different (p>0.05) between two treatments. All animals in T1 come to oestrus within 66 hours observation after CIDR removal. However, there were two (6.77%) animals did not show any oestrus behavior or come to heat within the observation period.
TIME TO OESTRUS SIGNS.
Table 4.2: The mean time (h ± SE) of animals to show oestrus behavioral.
58.4±2.303aValue within a column with the different superscripts (b) are significantly different (p<0.05)
Table 4.2 shown the mean time (± SE) of animal came to the each oestrus sign for both treatments. From four different sign, only tail flagging sign and standing sign show significant different (p< 0.05). There were big different hours observed between two treatments for animal came to standing sign which is the onset of oestrus. There are 16.33±0.181 h different between T1 and T2. For tail flagging sign, there were 8.33±0.913 h different between both treatments. However, there were slightly hour different observed for mounting sign and reddened vulva which were 7.4±0.765h and 4.72±0.013 h.
Table 4.3: Progesterone concentration (ng/mL ±SE) before CIDR insertion and 48 hours after CIDR removal.
Progesterone concentration (ng/mL ±SE)
Before CIDR insertion
48 hours after CIDR removal
8.313 ± 0.883a
7.952 ± 1.635a
Value within a column with the different superscripts (b) are significantly different (p<0.05)
Table 4.3 showed the progesterone concentration on the blood before CIDR insertion and 48 hours after CIDR insertion. There is no significant different (p>0.05) of the progesterone concentration mean in blood before CIDR insertion and 48 h after CIDR removal between T1 and T2 which is 0.361 ± 0.752 ng/mL and 1.208 ± 0.629 ng/mL difference. However, there is different of progesterone level between before CIDR insertion and 48 h after CIDR removal. The mean of progesterone level before CIDR insertion is higher compare to the mean of progesterone level 48 h after CIDR removal.
NUMBERS OF ANIMAL COME TO OESTRUS
The result shown that there are successive of two oestrus synchronization protocol on the numbers of animals come to oestrus. The result however did not support the outcome of study by Nasser (2008) where the result of the study showed significant different (p<0.05) in oestrus response when Boer does were treated with CIDR plus 50 µg cloprostenol and/or 250 IU PMSG for 17 days. There are 100% (21/21) of animals comes for oestrus for treatment with PMSG and 53.85% (7/13) for treatment without PMSG. The obvious different between this study and Nasser's is the length of treatment period and this may be the cause of the differences of the result between both studies. Too long of progestagen treatment will affect the follicle to become persistent and reduced the increases of extradiol during the regression of the corpus luteal (Taft et al., 1996). Gust et al.(1984) reported that the increasing of the estradiol after regression of corpus luteal will not help in increasing LH level that stimulate the oestrus..
In this experiment, there were two animals that did not come to estrus. It may be due to either in adequate oestradiol secretion or the animal shows silent oestrus without any overt signs of oestrus (Romano et al., 1998; Cardwell et al., 1998; Mustafa et al., 2007). Besides that, the absences of PMSG that contain the FSH and LH which help the increasing of LH level and trigger the oestrus also the factor of animal do not or late to come to oestrus.
TIME TO OESTRUS SIGN.
The mean time of animals to show oestrus sign were different between each sign. Tail flagging sign which is indicate the first sign of oestrus and standing sign which is the onset of oestrus shown the significant different (p<0.05). The significant different was expected and supported the study by Al-Sobail (2006) where the T1 oestrus synchronization protocol stimulate the oestrus more rapid (within 36 hour) and Nasser (2008) reported that the T1 protocol give shorter oestrus response. The study by Dogan (2008) also found that the protocol of T1 was gives not only early oestrus but also more compact and shorter time to onset of oestrus. However, in this study the CIDR was replaced by
The significant of both results may be due to the administrated of PMSG. The administration of PMSG will shorter the time to oestrus compared to the non PMSG treatment (Ucar et al., 2005) and compact the time to onset of oestrus (Freitas et al.,1996).
Besides that, the long mean time to animals show oestrus sign may be due to the hormonal response in the body same as the reason of the small number of animal that could not come to oestrus. It could be cause by inadequate or slow oestradiol secretion (Romano et al., 1998; Cardwell et al., 1998; Mustafa et al., 2007) and delayed the trigger of LH that important during oestrus.
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The means of progesterone concentration show no significant different (p>0.05) between T1 and T2 before CIDR insertion and 48 hours after CIDR removal. The level of progesterone was different between before CIDR insertion and 48 hours after CIDR removal may be due to the stages of oestrous cycle in the animals. The animals may be in the luteal phase before the insertion of CIDR. A study by Khanum et al. (2008) on the progesterone level in normal oestrus cycle in Dwarf goats shown that the progesterone level during luteal phase can peak into 7.7 ng/mL. However, the slightly higher of progesterone level in this study compare to Khanum's may be due to the breed of animals.
The lower means of progesterone level after 48 hours of CIDR removal between two treatments may be due to the effect of CIDR removal. The removal of CIDR that containing the progesterone cause the rapid declined of progesterone level in blood (Al- Sobaiyl, 2009; Khanum et al., 2008) and cause the exhibition of oestrus behavior.
Both of the treatments enable to give more percentages of animals come to oestrus. However, T1 is more effective on shortening the time to oestrus and compact the onset of oestrus. Thus as the conclusion, T1 which is CIDR treatment for 14 days with conjugate of 400 IU PMSG and 0.05 mg cloprostenol give better result in oestrus synchronization compare to CIDR treatment for 9 days with conjugate of 0.05 mg cloprostenol.
Due to the effectiveness of CIDR treatment for 14 days with conjugate of 400 IU PMSG and 0.05 mg cloprostenol in oestrus synchronization, further study should be done to compare the efficiency of the same protocol but changing into the different short period of the CIDR treatment in Boer goat in Malaysia.