The effects of Cosynch-56 protocol on pregnancy rates of cows and heifers presynchronized with a single dose of PGF 2α

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1 90 KACAR (C.) AND COLLABORATORS The effects of Cosych-56 protocol o pregacy rates of cows ad heifers presychroized with a sigle dose of C. KACAR 1, N. C. LEHIMCIOGLU 2, H. ORAL 1, S. YILDIZ 2, S. KAYA 1 *, M. KURU 1, A. K. ZONTURLU 3, S. M. ANCARCI 4, O. GUNGOR 5, S. ASLAN 6 1 Departmet of Obstetrics ad Gyecology, Faculty of Veteriary Medicie, Uiversity of Kafkas, 36300, Kars, Turkey 2 Departmet of Artificial Isemiatio ad Reproductio, Faculty of Veteriary Medicie, Uiversity of Kafkas, 36300, Kars, Turkey 3 Departmet of Obstetrics ad Gyecology, Faculty of Veteriary Medicie, Uiversity of Harra, 63200, Saliurfa, Turkey 4 Departmet of Obstetrics ad Gyecology, Faculty of Veteriary Medicie, Uiversity of Balikesir, 10145, Balikesir, Turkey 5 Departmet of Obstetrics ad Gyecology, Faculty of Veteriary Medicie, Uiversity of Mehmet Akif Ersoy, 15030, Burdur, Turkey 6 Departmet of Obstetrics ad Gyecology, Faculty of Veteriary Medicie, Uiversty of Akara, 06110, Akara, Turkey *Correspodig author: semra-kafkas@hotmail.com 1 This study has bee preseted as oral commuicatio i the 4th Cogress of Veteriary Gyecology Atalya, Turkey, 4-7 November 2010 ABSTRACT The objective of this study was to evaluate pregacy rates to timed artificial isemiatio (TAI) followig presychroizatio with a sigle dose of te days before CoSych-56 protocol i Brow Swiss crossbred cows ad heifers. Group I (GI) cows (=89) ad heifers (=39) received GF2α te days prior to Cosych-56 protocol while Group II (GII) cows (=82) ad heifers (=38) received CoSych-56 protocol oly. was evaluated usig ultrasoography days after TAI. rates did ot differ sigificatly betwee GI ad GII (34.4% ad 28.3 %, respectively, >0.05). However, pregacy rates differed sigificatly (<0.05) betwee cows ad heifers i GII (34.1% ad 15.7%, respectively). Furthermore, pregacy rates of heifers i GI was sigificatly higher tha that of heifer i GII (<0.01, 41.0% ad 15.7%, respectively). Notably, pregacy was ot achieved i GII heifers with plasma 4 values < 1g/ml. I coclusio, presychroizatio with before Cosych-56 protocol did ot ehace pregacy rates i Brow Swiss cows but did i heifers. Also, high 4 levels may ehace overall pregacy rates of cows ad heifers subjected to the Cosych-56 protocol. Keywords: cow, heifer, presych, Cosych-56, pregacy rate RÉSUMÉ Les effets du protocole Cosych-56 sur le taux de gestatio de vaches et géisses pré-sychroisées avec ue dose uique de GF2α L objectif de cette étude était d évaluer le taux de gestatio après isémiatio artificielle (TAI) suite à ue présychroisatio avec ue dose uique de dix jours avat u protocole Cosych-56 chez des vaches et géisses croisées de race Brow Swiss. Le groupe I (GI) costitué de 89 vaches et de 39 géisses a reçu ue ijectio de dix jours avat le protocole CoSych-56 tadis que le groupe II (GII) costitué de 82 vaches et de 38 géisses a suivi le protocole Cosych-56 seul. La gestatio a été évaluée e utilisat l échographie jours après TAI. Les taux de gestatio e diffèret pas sigificativemet etre GI et GII (34,4% et 28,3%, respectivemet). Cepedat, le taux de gestatio différait sigificativemet ( <0,05) etre les vaches et les géisses e GII (34,1% tt 15,7%, respectivemet). E outre, les taux de gestatio chez les géisses e GI était sigificativemet plus élevée ( <0,01) que celui des géisses e GII (41,0% et 15,7%, respectivemet). La gestatio a pas été observée chez les géisses GII ayat des cocetratios plasmatiques e progestéroe <1 g/ ml. E coclusio, la présychroisatio avec avat u protocole Cosych-56 a pas amélioré le taux de gestatio chez les géisses croisées Brow Swiss mais pas chez les vaches. E outre, les iveaux de progestéroe élevés amélioret le taux de gestatio chez les vaches et géisses soumis au protocole Cosych-56. Mots-clés: vache, géisse, présychroisatio, Cosych-56, gestatio, progestéroe Itroductio The Ovsych protocol developed by ursley et al. [21] is kow as timed artificial isemiatio (TAI). This protocol stimulates bovie ovulatio by meas of the sequetial admiistratio of GRH, followed by seve days later, ad lastly, a fial GRH ijectio 48 hours after the ijectio. I a previous study coducted to determie the optimum isemiatio time i cows, pregacy rates were foud to be high durig the 16 hours post-admiistratio of the fial GRH dose, while pregacy rates were observed to have falle i procedures performed after 24 hours [23]. I lactatig cows, the use of the Ovsych protocol betwee days 5 ad 12 of the cycle icreased pregacy rates at a higher level, compared to its use at ay other time of the cycle [29]. Whe the Ovsych protocol is iitiated at ay time durig the cycle, the sychroizatio rates achieved after admiisterig a secod GRH dose are reported to vary betwee 71.4 ad 87% [9, 15, 29]. The ijectio of a sigle dose of 10 or 12 days prior to the Ovsych protocol is reported to improve pregacy rates i cows [5, 19]. The ijectio of a sigle dose of 3 days, 10 days, or 12 days prior to timed artificial isemiatio has bee reported ot to produce successful results for pregacy rates [4, 16, 17]. Cartmill et al. [4]

2 EFFECTS OF COSYNCH-56 ROTOCOL ON REGNANCY RATES 91 foud that presychroizatio with 12 days prior to the Ovsych protocol reported ot to ehace pregacy rates i multiparous cows ad cows i their first lactatio. erformig artificial isemiatio simultaeously with the secod GRH ijectio of the Ovsych protocol is kow as the Cosych protocol [12]. This protocol ot oly saves time, but also reduces the umber of procedures required for each cow [26]. I the resych+ovsych protocol used i cows, if the timig of the secod GRH ijectio of the Ovsych protocol ad artificial isemiatio is arraged betwee 48 ad 72 hours, this is referred to as the modified Cosych protocol [20]. Sterry et al. [26] did ot fid ay statistically sigificat differece betwee the pregacy rates achieved i lactatig cows with the use of the Cosych-48 or Cosych-72 protocols after the resych procedure. Some studies have demostrated o statistical differece betwee the pregacy rates achieved with the Ovsych ad Cosych protocols i cows [12, 24]. The aim of the study was to evaluate pregacy rates to TAI after presychroizatio with a sigle dose of te days before Cosych-56 protocol. The aim was to stimulate ovulatio at the most appropriate time so as to achieve high pregacy rates i the herd, by iitiatig the Cosych-56 protocol betwee days 5-12 of the sexual cycle, 10 days after the ijectio. Material ad methods ANIMALS This study was coducted usig crossbred Brow Swiss cows ad heifers grazig free rage pastures betwee April to July, The cows ad heifers were selected radomly. It was determied that the cows i Group I were betwee ±88.47 days postpartum ad the cows i Group II were betwee ±74.53 days postpartum (>0.05). The body coditio score of the aimals was measured as described by Edmoso et al. [6], o a scale of 1 (emaciated) to 5 (obese). The body coditio score (BCS) was 2.28±0.43 i Group I ad 2.40±0.47 i Group II (>0.05). The mea milk yield per cow per lactatio was 3156±1495 litres i Group I ad 3291±1555 litres i Group II (>0.05). It was determied that the cows were milked oce a day aroud 7-8 pm durig the period of lactatio. The average age of the cows was 5.2±1.6 years i Group I ad 5.0±1.7 years i Group II. The average age of the heifers i Group I ad Group II at the oset of the study was determied to be 2.3±0.7 years ad 2.2±0.6 years, respectively. STUDY ROCEDURE Group I (=128) The cows averaged 103 d i milk at the time of the first ijectio. A sigle itramuscular (IM) 2-ml dose of (Estrumate, 250 µg cloprosteol, CEVA-DIF, Istabul, Turkey) was give to the cows (=89) ad heifers (=39), ad 10 days later the Cosych-56 protocol was iitiated. Accordig to this protocol, a 2-ml IM dose of GRH (Ovareli, 50 µg Goadoreli diacetate tetrahydrate, CEVA-DIF, Istabul, Turkey) was admiistered o day 0. Seve days later, the aimals received a IM ijectio of 2 ml of (Estrumate ). Fifty-six hours after admiisterig, artificial isemiatio was performed. Isemiatio was performed by depositig sperm ito the corpus uteri. Immediately after this procedure, a 2-ml IM ijectio of GRH (Ovareli ) was admiistered. Two experieced veteriarias performed all AI. Group II (=120) The cows averaged 113 d i milk at the time of the first ijectio. The cows (=82) ad heifers (=38) i this group were ot give before the Cosych-56 protocol for presychroizatio. The other procedures applied were the same as i the first group. Group I (=128) after 56 h day -10 day 0 day 7 day 10 GRH AI+GRH Group II (=120) after 56 h day -10 day 0 day 7 day 10 Figure 1: Treatmet protocols i cows ad heifers ROGESTERONE ANALYSIS Jugular blood samples were take from all aimals i both groups ad collected ito EDTA-coated tubes before admiisterig 10 days before the Cosych-56 protocol, o the day the Cosych-56 protocol bega (day 0), ad before admiisterig o day 7 of the Cosych-56 protocol. lasma was extracted from these samples with refrigerated cetrifugatio at 3000 rpm ad stored i a deep freezer at C to measure progesteroe levels. rogesteroe measuremet was coducted usig the radioimmuoassay (RIA) method with commercial kits (Immuotech, Frace), ad i accordace with the maufacturer s istructios. The itraassay ad iterassay coefficiets of variatio of the kits that were used were 6.5% ad 7.2%, respectively. STATISTICAL ANALYSIS GRH AI+GRH Statistical aalyses were performed usig SAS (Versio 9.2, SAS Istitute, Ic., Cary, NC). Microsoft Excel (Microsoft Corp., Redmod, WA) was used for the statistical aalysis of the idividual characteristics of the aimals. The T-test was used to determie the statistical results for the BCS of the cows ad heifers i the two groups, as well as for milk productio. The pregacy rates were aalysed usig the chi-square test. A value of <0.05 was cosidered statistically sigificat.

3 92 KACAR (C.) AND COLLABORATORS Results rates achieved i the cows ad heifers followig the first isemiatio are preseted i Table I. Evaluatio of both cows ad heifers demostrated that o statistically sigificat differece existed betwee the total pregacy rates achieved i GI ad GII (<0.05, 34.4% ad 28.3%, respectively). While the pregacy rates of the cows ad heifers i GI did ot differ sigificatly (31.5% ad 41.0%, respectively, >0.05), the differece betwee the pregacy rates achieved i the cows ad heifers i GII o iitial isemiatio was statistically sigificat (<0.05; 34.1% ad 15.7%). The pregacy rate of the heifers i GI was also sigificatly higher tha it was i GII (<0.01; 41.0% ad 15.7%). The total pregacy rates of the cows ad heifers icluded i GI ad GII, accordig to the plasma progesteroe level measured at the time of the first GRH ijectio of the Cosych 56 protocol (Day 0) beig lower or higher tha 1g/ml, are show i Table II. It was ascertaied that the pregacy rate of the aimals icluded i GI, which had a plasma progesteroe level 1g/ml, was higher tha that of those icluded i GII. The differece observed betwee the two groups was foud to be statistically sigificat (=0.04). The pregacy rates of the aimals with serum progesteroe levels <1g/ml did ot differ sigificatly. The cows ad heifers icluded i the two groups were compared for their pregacy rates determied accordig to the plasma progesteroe level at the time of the first GRH ijectio of the Cosych 56 protocol (Day 0) beig 1g/ ml (H) or <1g/ml (L). I the cows ad heifers with plasma progesteroe levels higher tha 1g/ml, a ijectio prior to the Cosych protocol was determied to have icreased pregacy rates sigificatly i both cows (=0.03) ad heifers (=0.008). No differece was determied betwee the pregacy rates of the cows ad heifers with plasma progesteroe levels lower tha 1 g/ml (Table III). Discussio The coicidece of the first GRH ijectio of the Ovsych protocol with the first three days of the follicular Treatmet protocol Cows Heifers Total a:b: p<0.01; A:B: p<0.05 GI 31.5 (28/89) 41.0 a (16/39) 34.4 (44/128) GII 34.1 A (28/82) 15.7 b,b (6/38) 28.3 (34/120) Table I: rates o first isemiatio i cows ad heifers usig the treatmet protocol 4 (H) Groups Cows+Heifers % GI 54 GII a (23/54) 25.0 b (17/68) a:b: p= (L) Groups Cows+Heifers % GI 74 GII (21/74) 32.7 (17/52) 0.6 Table II: rates detected i both groups (cows ad heifers) for plasma progesteroe levels 1g/ml (H) ad <1g/ml (L) at the time of the first GRH ijectio of the Cosych 56 protocol (Day 0)

4 EFFECTS OF COSYNCH-56 ROTOCOL ON REGNANCY RATES 93 wave causes the domiat follicles, existig at the time of the ijectio, to lose their domiace ad a ew follicular wave to start. The domiat follicle formed after the ew wave does ot reach a size adequate for ovulatio at the time of the secod GRH ijectio [22]. It has bee reported that the iitiatio of the Ovsych protocol betwee days 5 to 12 of the cycle, icreases the ovulatory respose at the time of the first GRH ijectio [2, 29] as well as the pregacy rate per isemiatio [29]. While some research suggest that presychroizatio with prior to the Ovsych protocol icreases the pregacy rates achieved [7, 10, 18], some other research have idicated o sigificat differece to occur i pregacy rates with presychroizatio [12, 16, 17, 24]. Eve though the sychroizatio rate achieved is higher i cows tha i heifers whe the resych protocol is applied prior to the Ovsych protocol, the pregacy rates of the cows were foud to be sigificatly lower tha that of the heifers. I heifers were sigificatly higher with progesteroe levels higher tha 1g/ml prior to ijectio [14]. I the preset study, it was observed that while the admiistratio of prior to the Cosych protocol did ot icrease the pregacy rate of the cows, it sigificatly icreased the pregacy rate of the heifers (<0.01). It is clear that heifers respod better to the effect of high levels of progesteroe o the uterus ad ovaries, depedig o better uterie health, variatios i follicular developmet ad the relatioship betwee the corpus luteum ad uterie axis [1, 3, 13, 14, 27]. Researchers attribute the low pregacy rates achieved with the Cosych-56 protocol without previous admiistratio of to the corpus luteum (CL), formed as a result of the iductio of small follicles after GRH ijectios i heifers, havig a short lifespa ad reducig fertility [28]. Gordo et al. [14] determied that pregacy rates i heifers with a progesteroe level higher tha 1 g/ ml prior to the ijectio were sigificatly higher. These researchers also foud that pregacy rates i cows ad heifers with progesteroe levels greater tha 1 g/ml durig the first GRH ijectio of the Ovsych protocol were sigificatly higher tha those of cows ad heifers with progesteroe levels less tha 1 g/ml. Similarly, i the preset study, it was determied that the admiistratio of prior to the Cosych protocol i cows (=0.03) ad heifers (=0.008) with plasma progesteroe levels higher tha 1 g/ml at the time of the first GRH ijectio of the Cosych protocol sigificatly icreased pregacy rates. O the other had, o sigificat differece was observed i the pregacy rate of aimals with plasma progesteroe levels lower tha 1g/ml followig the applicatio of this procedure. This suggests that the admiistratio of prior to the Cosych-56 protocol iduces a better respose i aimals (cows ad heifers) with a periodical CL. The reaso for the pregacy rates of the cows ad heifers i GI beig high could be either the domiat follicle cotaiig a fertile oocyte with a existig CL that produces progesteroe or the domiat follicle cotiuig to grow util it matures ad ovulatio occurs, as reported by Smith ad Steveso [25]. Furthermore, studies have reported that high progesteroe cocetratios prior to isemiatio have a positive effect o the developmet of ovulatory follicles [14, 18]. High levels of fertility have also bee demostrated i aimals affected by high cocetratios of progesteroe prior to the ijectio [8]. Similarly, the preset study demostrated that the admiistratio of a sigle dose of to aimals with high plasma progesteroe levels before the iitiatio of the Cosych protocol icreased pregacy rates. I coclusio, it was determied that the admiistratio of a sigle dose of prior to the Cosych protocol did ot icrease pregacy rates i cows, but sigificatly icreased pregacy rates i heifers. It was cocluded that pregacy rates could be raised i heifers ad cows if procedures are coducted whe there is a active corpus luteum with high levels of progesteroe. Ackowledgemets This study was supported by the Scietific Research roject Coordiator s Office at Kafkas Uiversity (roject o: 2010-VF-09). 4 (H) GI 4 (H) GII Cows a (16/41) b (16/54) a:b:p=0.03 Heifers c (7/13) d (1/14) c:d:p= (L) GI 4 (L) GII Cows (12/47) (12/29) 0.1 Heifers (9/27) (5/23) 0.3 Table III: rates of cows ad heifers i both groups accordig to the plasma progesteroe levels at the time of the first GRH ijectio of the Cosych 56 protocol (Day 0) beig 1g/ml (H) or <1g/ml (L).

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