Luteolysis and pregnancy outcomes after change in dose delivery of prostaglandin F2α in a 5-day timed artificial insemination program in dairy cows

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1 Knss Agriculturl Experiment ttion Reserch Reports Volume Issue 2 Diry Reserch (94-24) Article 9 24 Luteolysis nd pregnncy outcomes fter chnge in dose delivery of prostglndin F2α in -dy timed rtificil insemintion progrm in diry cows Jeffrey. tevenson tephnie Leenn Pulley cott L. Hill Follow this nd dditionl works t: Prt of the Diry cience Commons Recommended Cittion tevenson, Jeffrey.; Pulley, tephnie Leenn; nd Hill, cott L. (24) "Luteolysis nd pregnncy outcomes fter chnge in dose delivery of prostglndin F2α in -dy timed rtificil insemintion progrm in diry cows," Knss Agriculturl Experiment ttion Reserch Reports: Vol. : Iss This report is rought to you for free nd open ccess y New Pririe Press. It hs een ccepted for inclusion in Knss Agriculturl Experiment ttion Reserch Reports y n uthorized dministrtor of New Pririe Press. Copyright 24 Knss tte University Agriculturl Experiment ttion nd Coopertive Extension ervice. Contents of this puliction my e freely reproduced for eductionl purposes. All other rights reserved. rnd nmes ppering in this puliction re for product identifiction purposes only. No endorsement is intended, nor is criticism implied of similr products not mentioned. K-tte Reserch nd Extension is n equl opportunity provider nd employer.

2 Luteolysis nd pregnncy outcomes fter chnge in dose delivery of prostglndin F2α in -dy timed rtificil insemintion progrm in diry cows Astrct Three experiments were conducted to determine if lrger dose of prostglndin F2α () dministered on dy of -dy Ovsynch timed rtificil insemintion (AI) progrm would induce regression of the corpus luteum to fcilitte AI nd pregnncy outcomes similr to trditionl -dy progrm with two doses of. When pplying -dy progrm, cows tht ovulte in response to the first GnRH injection hve new corpus luteum (CL) tht is 2 dys younger when is dministered in - versus 7-dy progrm. To regress successfully the younger CL, second injection of must e given 24 hours fter the first injection to prevent reduced pregnncy rte fter the timed AI. These experiments demonstrted tht dministering mg ( ml Lutlyse) on dy produced luteolysis s efficiently s 2 mg ( ml Lutlyse) dministered on dys nd when the cut point for progesterone ws ng/ml 72 hours fter the first injection or 4 hours fter the lrger dose. In contrst, when the cut point ws. ng/ml, the lrger dose of ws less effective. Pregnncy outcomes in cows did not differ etween tretment doses except in one herd (Exp. 3). Although pregnncy outcomes were reduced only in one herd with the lrger dose, this difference my e confounded with the erlier injection of the second GnRH injection hours efore timed AI, rther thn filure of luteolysis in response to the lrger dose of. Delying the timing of AI, injection of the second GnRH, or oth my e wrrnted to llow sufficient time for progesterone to decrese to sl concentrtions in response to lrger dose of on dy to prevent reduction in fertility.; Diry Dy, 24, Knss tte University, Mnhttn, K, 24; Diry Reserch, 24 is known s Diry Dy, 24 Keywords Diry Dy, 24; Knss Agriculturl Experiment ttion contriution; no. --; Report of progress (Knss Agriculturl Experiment ttion nd Coopertive Extension ervice); ; Lutel tissue; Luteolysis; Ovultion; Progesterone; Pregnncy rte Cretive Commons License This work is licensed under Cretive Commons Attriution 4. License. This Reserch Report rticle is ville in Knss Agriculturl Experiment ttion Reserch Reports: kesrr/vol/iss2/9

3 Diry Reserch 24 Luteolysis nd Pregnncy Outcomes fter Chnge in Dose Delivery of Prostglndin F 2α in -dy Timed Artificil Insemintion Progrm in Diry Cows J.. tevenson,. L. Pulley, nd. L. Hill ummry Three experiments were conducted to determine if lrger dose of prostglndin F 2α () dministered on dy of -dy Ovsynch timed rtificil insemintion (AI) progrm would induce regression of the corpus luteum to fcilitte AI nd pregnncy outcomes similr to trditionl -dy progrm with two doses of. When pplying -dy progrm, cows tht ovulte in response to the first GnRH injection hve new corpus luteum (CL) tht is 2 dys younger when is dministered in - versus 7-dy progrm. To regress successfully the younger CL, second injection of must e given 24 hours fter the first injection to prevent reduced pregnncy rte fter the timed AI. These experiments demonstrted tht dministering mg ( ml Lutlyse) on dy produced luteolysis s efficiently s 2 mg ( ml Lutlyse) dministered on dys nd when the cut point for progesterone ws ng/ml 72 hours fter the first injection or 4 hours fter the lrger dose. In contrst, when the cut point ws. ng/ml, the lrger dose of ws less effective. Pregnncy outcomes in cows did not differ etween tretment doses except in one herd (Exp. 3). Although pregnncy outcomes were reduced only in one herd with the lrger dose, this difference my e confounded with the erlier injection of the second GnRH injection hours efore timed AI, rther thn filure of luteolysis in response to the lrger dose of. Delying the timing of AI, injection of the second GnRH, or oth my e wrrnted to llow sufficient time for progesterone to decrese to sl concentrtions in response to lrger dose of on dy to prevent reduction in fertility. Key words: lutel tissue, luteolysis, ovultion, progesterone, pregnncy rte Introduction Most timed AI (TAI) progrms pply comintion of GnRH nd prostglndin F 2α () to control folliculr wve initition, ovultion, nd corpus luteum (CL) regression (luteolysis) in diry herds efore first or repet AI. These progrms generlly consist of injecting GnRH (dy ), stndrd 2-mg dose of on dys nd (-dy progrm) or single dose of on dy 7 (7-dy progrm), GnRH t hours (Ovsynch-) or 72 hours (CO-ynch-72) fter with TAI dministered on dy (-dy progrm) or dy (7-dy progrm). Unless is dministered on dys nd in -dy progrm, luteolysis fils to occur in proportion of cows tht formed new CL fter GnRH dministrtion on dy. A recent report in nonlctting cows modified the -dy progrm y pplying lrger dose (2% of norml) of nlog on dy nd compred tht with stndrd doses of on dys nd. Results indicted tht the lrger dose of on dy (which required less niml hndling) produced luteolytic outcomes nd finl preovultory fol- 22

4 Diry Reserch 24 licle dimeter similr to the stndrd doses of on dys nd. In study consisting of 2 experiments conducted in lctting diry cows, estrous cycles were presynchronized efore -d Ovsynch progrm to test whether single lrge dose (2% of control) of either Estrumte or cloprostenol ( mg) or Lutlyse or dinoprost ( mg) dministered on dy would produce cceptle rtes of luteolysis, pregnncy, or oth compred with two stndrd split doses (. or 2 mg, respectively) dministered on dys nd. In the first experiment, cows were treted with. mg cloprostenol on dys nd (d = GnRH- s in Figure ) compred with mg cloprostenol (doule dose) on dy. More luteolytic filures occurred, nd pregnncy outcomes were reduced y s much s one-third in cows receiving the -mg dose of cloprostenol in the first experiment. In the second experiment of similr design, -mg dose of dinoprost ( ml Lutlyse) dministered on dy resulted in reduced pregnncy outcomes compred with the stndrd 2-mg doses dministered on dys nd. In contrst, incresing the dose of cloprostenol from. to.7 mg (2 to 3 ml) on dy 7 of 7-dy progrm incresed lutel regression in multiprous, ut not in primiprous cows, resulting in improved pregnncy outcomes t 39 dys fter AI. We hypothesized tht dministering mg of to lctting diry cows on dy would produce similr rtes of luteolysis s mesured y decresed CL tissue re nd serum progesterone without compromising pregnncy outcomes. Our ojectives were to: () determine the effect of the stndrd control dose of on dys nd with single lrger (2% of control) dose of on dy in lctting diry cows efore first postprtum AI (Experiment ) on lutel tissue re nd progesterone concentrtions nd efore repet services on progesterone concentrtions (Experiment 2); nd (2) ssess luteolysis (one herd) nd pregnncy outcomes in two seprte herds (Experiment 3). Mterils nd Methods Experiment Estrous cycles were presynchronized (GnRH [2 ml Fctrel, Pfizer Animl Helth, Mdison, NJ] 7 dys efore dministrtion of 2 mg of [ ml Lutlyse, Pfizer Animl Helth]) in lctting Holstein cows ( primiprous nd 43 multiprous). Eleven dys lter, cows were enrolled rndomly within prity in -dy Ovsynch-72 progrm (2 to 7 DIM) nd tretments were dministered s illustrted in Figure (control cows [2-mg dose of on dys nd ; n = 3] nd treted cows [single - mg dose of on dy ; n = 3]). On dy, follicles nd originl CL were mpped nd mesured y trnsrectl ultrsonogrphy (. MHz liner-rry trnsducer, Alok V, Corometrics Medicl ystems, Inc., Wllingford, CT). On dys through 9, ovrin follicles, new GnRH-induced CL, nd originl CL were mesured. The lrgest ovrin follicle on dy ws trced ck to its first ppernce to determine the puttive preovultory follicle dimeter. phericl cvity-free re of lutel structures ws clculted. Luteolysis ws defined to occur when concentrtions of progesterone were ng/ml on dy nd < ng/ ml on dy. lood serum ws ssyed y rdioimmunossy for progesterone in oth experiments. Assy sensitivity ws.9 ±. pg/ml. Inter- nd intr-ssy coefficients of vrition for 4 ssys were. nd 7.9%, respectively. 23

5 Diry Reserch 24 Pregnncy ws dignosed y trnsrectl ultrsonogrphy on dy 32 fter TAI. A positive pregnncy outcome required presence of nechoic uterine fluid nd CL 2 mm in dimeter or nechoic uterine fluid nd presence of n emryo with hertet. Experiment 2 Cows dignosed not pregnnt to previous AI were treted with GnRH on dy nd ssigned rndomly to the sme two tretments s descried in Exp. (Figure ). lood ws collected on dys,,, nd. Only dt from 3 cows hving serum progesterone ng/ml on dy were nlyzed. Concentrtions of progesterone nd occurrence of luteolysis were nlyzed s in Exp.. Experiment 3 Weekly clusters of lctting diry cows were enrolled in two tretments (Figure 2) during n entire clendr yer s prt of -dy timed AI Resynch-Ovsynch progrm (GnRH dys efore [dy ; GnRH-] nd [p.m. on dy 7; GnRH-2] or 72 hours [dy ; GnRH-2] fter with timed AI on dy ). Enrollment occurred on the sme dy (dy ) s negtive pregnncy dignosis (3 to 3 dys fter lst AI in herd or dys 34 to 4 in herd 2). Control cows received 2-mg dose of ( ml Lutlyse) on dys nd (2 2), nd treted cows received one single -mg dose of on dy ( ; ml Lutlyse). Cows in herd were locked y prity nd ssigned rndomly to tretments: 2 2 (n = 42) or (n = 4). In herd 2, even-tgged cows received the 2 2 (n = 422) tretment, nd odd-tgged cows received (n = 4) tretment. ody condition scores were ssessed ( = thin nd = oese) either weekly in herd or monthly in herd 2. In herd, ovries were scnned y trnsrectl ultrsonogrphy to determine the numer of CL nd numer of ovrin follicles mm in dimeter on dy. usequent to tretment nd timed AI, pregnncy ws dignosed y trnsrectl ultrsonogrphy 3 to 3 dys fter AI. In herd 2, pregnncy ws determined y plption per rectum of the uterus nd its contents on dys 34 to 4 fter AI. In oth herds, second pregnncy confirmtion ws conducted etween nd 7 dys post-ai. In herd, lood ws collected on dys,,, nd. lood serum ws ssyed for progesterone y rdioimmunossy. Assy sensitivity ws.3 ±. pg/ml. Inter- nd intr-ssy coefficients of vrition for ssys were.2 nd 4.%, respectively. Results nd Discussion Experiment On dy, of cows hd t lest CL nd hd 2 or more CL, wheres cows ( cows per tretment) hd no CL. On dy, 34 of cows hd lest new CL, nd cows hd 2 or more new CL. Therefore, the ovultion response to GnRH on dy ws 3 of (.%). Numers of cows with, 2, or 3 totl CL (originl plus new CL) on dy were s follows: CL: 2 vs. 3; 2 CL: 3 vs. 4; nd 3 or more CL: vs. 3 for control nd -mg cows, respectively. Originl lutel tissue re ws similr on dy ut differed etween tretments on dy (P =.) nd dy 7 (P =.9) nd tended (P =.) to e less on dy for the 24

6 Diry Reserch 24 control. In contrst, no differences were detected etween tretments for GnRH-induced lutel tissue re. Concentrtions of progesterone differed (P =.) only on dy etween tretments (Figure 3; upper pnel). Luteolysis occurred in ll 3 controls ut filed to occur in 2 of 3 (.7%) -mg cows in which no CL were present on dy, ut or 3 new GnRHinduced CL were present on dy in the 2 cows with luteolytic filure. Pregnncy outcomes were 2 of 3 (4%) for control cows nd of 3 (%) for - mg cows. One control cow ws culled efore pregnncy ws determined. Experiment 2 Concentrtions of progesterone differed etween tretments only on dy (Figure 3; lower pnel). Luteolysis occurred in ll 29, -mg cows ut filed to occur in 2 of 34 (.9%) controls. Pregnncy outcomes t dy 32 fter TAI were 7 of 33 (2%) for control cows nd 3 of 29 (4%) for -mg cows. One control cow ws culled efore pregnncy dignosis. Experiment 3 Progesterone. Concentrtions of progesterone differed (P <.) etween tretments on dy nd. More (P <.) thn 2 2 cows hd concentrtions of progesterone ng/ml on dy, ut similr proportions of cows in ech tretment hd low (< ng/ml) concentrtions y dy (Figure 4). Progesterone lso differed mong cycle sttuses on dy nd, ut not etween tretments, which hd not yet een dministered. oth nestrous nd new-cl cows in oth tretments hd low concentrtions on dy nd differed (P <.) from those of erly- nd lte-cycle cows, which differed (P <.) from one nother. On dy, concentrtions of progesterone were ner seline in lte-cycle cows, suggesting erly spontneous luteolysis efore tretment on dys or, wheres concentrtions in new CL cows incresed (P <.) y 7.4 to.3 times from dy to, indicting ovultion occurred fter GnRH- on dy. Concentrtions of progesterone in erly-cycle cows were elevted on oth dys nd (Figure 4). Reltive differences mong cycle sttuses for cows in oth tretments on dy were consistent with wht ws oserved on dy, except on dy, new-cl nd erly-cycle cows no longer differed from one nother. y dy, concentrtions of progesterone did not differ mong cycle sttuses for cows in either tretment. Luteolysis. Cows treted with mg on dy were more (P =.3) likely to hve incomplete luteolysis when the cut point on dy ws <. ng/ml. In contrst, when the cut point ws < ng/ml, no difference ws detected etween tretments (Tle ). Luteolysis in cows most likely to fil to respond to (erly-cycle nd new-cl cows) did not differ etween erly-cycle nd new-cl cows (. vs. 3.%) for the <. ng/ ml cut point or for the < ng/ml cut point (97.4 vs. %), respectively. Cycle sttus within tretment reflected the overll tretment effects for luteolysis. Although tretment differences were not detected for erly-cycle cows etween tretments, luteolysis in the 2 2 vs. cows reflected the overll tretment differences 2

7 Diry Reserch 24 in Tle t the <. ng/ml cut point (94. vs. 7.2%; P =.49) nd t the < ng/ml cut point (7. vs. 79.3%; P =.9), respectively. Defined luteolysis ws not ffected y either C or numer of follicles > mm ssessed on dy. In response to tretment on dy, concentrtions of progesterone on dy decresed in 2 2 cows in response to the first of two 2-mg injections nd differed (P =.) from those in the -mg tretment for erly-cycle nd new-cl cows only, wheres no tretment differences were detected in lte-cycle nd nestrous cows (Figure 4). Although concentrtions of progesterone hd decresed further y dy, difference (P =.) etween tretments existed only for erly-cycle cows, indicting tht erly-cycle cows lso my hve hd dditionl new lutel tissue in the form of new CL tht ws resistnt to the luteolytic effects of. Pregnncy Outcomes. Pregnncy per AI t the first nd second dignosis period ws reduced in nestrous nd lte-cycle cows compred with erly-cycle nd new-cl cows in oth tretments for cows in herd. Pregnncy per AI (3 to 3 dys post-ai) for cows in herd with luteolysis defined t the cut point of <. ng/ml did not differ etween 2 2 vs. tretments (4.% [n = ] vs. 37.% [n = ]) or t the cut point of < ng/ml (4.3% [n = ] vs. 4.% [n = ]), respectively. Neither prity (P >.) nor C hd ny effect (P >.3) on pregnncy per AI in herd. Pregnncy outcomes t 3 to 4 dy differed (P <.) mong herds, ut the cows tended (P =.7) to hve lesser fertility only in herd 2 (Tle 2). This tretment difference in herd 2 ws confirmed (P =.3) t the lter pregnncy dignosis in herd 2 (Tle 2). We conclude tht one lrge dose ( mg ) dministered on dy is luteolytic (regressed the CL) using cut point of ng/ml, which is consistent with erlier reports in non-lctting nd lctting cows (Exp. nd 2), ut not so when more conservtive cut point of. ng/ml ws pplied (Exp. 3). Although progesterone my eventully decrese to sufficient concentrtions (complete functionl luteolysis) with time, it my not chieve sufficiently sl concentrtions in some cows to prevent reduced pregnncy outcomes, prticulrly those defined s erly-cycle, hving new CL on dy, or oth. Although pregnncy outcomes were reduced only in herd 2 with tretment compred with herd, this difference my e confounded with the erlier injection of GnRH-2 hours efore timed AI in herd 2 rther thn filure of luteolysis to the lrger dose of. Delying the timing of AI, injection of GnRH-2, or oth, my e wrrnted to llow sufficient time for progesterone to decrese to sl concentrtions in response to lrger dose of on dy to prevent reduction in conception. 2

8 Diry Reserch 24 Tle. Luteolysis t 2 different cut points for cows treted with 2 2 or mg of F 2α in herd (Exp. 3) 9% confidence Tretment 2 Luteolysis (%) Odds rtio intervl P-vlue <. ng/ml x Referent x < ng/ml x 2. Referent x 9.3 < Progesterone ng/ml on dy nd either <. or < ng/ml 72 hours lter on dy. 2 Cows received either 2 mg F 2 () on dys nd or mg on dy s prt of -dy Resynch- Ovsynch progrm (d = GnRH-). Tle 2. Pregnncy per AI in oth herds t 3 to 4 nd to 7 dys post-ai (Exp. 3) Tretment tge of pregnncy, dys 2 2 P-vlue 3 to 4 % (n) Herd 37.2 (39) 33.3 (34).7 Herd (422) 9. (4).7 to 7 Herd 3.3 (39) 2.2 (34). Herd (422).9 (4).3 Cows received either 2 mg F 2 () on dys nd or mg on dy s prt of -dy Resynch- Ovsynch progrm (d = GnRH-). 27

9 Diry Reserch 24 GnRH- 2 mg 2 mg GnRH-2 + TAI GnRH dys dys dy 2 dys 7 dys GnRH- mg GnRH-2 + TAI dys dys 2 dys Figure. cheme of tretments nd mesurements for Experiments nd 2. In Experiment, estrous cycles were presynchronized y injecting μg GnRH nd 2 mg of eginning etween 2 nd 7 dys in milk. Cows were ssigned rndomly to receive either 2-mg doses of on dys nd or -mg dose of on dy. Ovrin structures were mesured y trnsrectl ultrsonogrphy () nd mpped on dy nd dys through 9. oth originl CL on dy nd GnRH-induced CL identified on dy were mesured nd monitored for dimeter nd lutel re (CL cvity re ws deducted from totl lutel re). lood smples () were collected efore ech ovrin scn. 7 9 GnRH- 2 mg 2 mg TAI dys dy 2 dys GnRH- mg TAI dys dy 2 dys Figure 2. Experiment 3 tretment schemes in two herds. In herd, cows were ssigned rndomly to receive either 2 mg F 2 () on dys nd or -mg dose of on dy. lood smples were collected on dys,,, nd to mesure progesterone. In herd 2, even-tgged cows received 2 mg on dys nd, nd odd-tgged cows received mg on dy. The second GnRH (GnRH-2) injection ws dministered on the fternoon of dy 7, nd timed AI (TAI) occurred on the morning of dy in herd 2, ut TAI occurred in herd when GnRH-2 ws dministered on dy (72 hours fter the first 2-mg tretment). 2

10 Diry Reserch 24 7 Exp. P =. 2 mg on dy nd (n = 3) mg on dy (n = 3) Progesterone, ng/ml Exp. 2 P =. 2 mg on dy nd (n = 34) mg on dy (n = 29) Progesterone, ng/ml Dys from GnRH injection on dy Figure 3. Concentrtions of progesterone in control (2-mg doses of on dys nd ) nd treted cows ( mg of only on dy ) for cows in Exp. (upper pnel) nd Exp. 2 (lower pnel). Concentrtions differed (P =.) etween tretments only on dy in oth experiments. 29

11 Diry Reserch 24 Progesterone, ng/ml x 2 mg c d c Anestrus (n = 2) Erly cycle CL (n = 2) Lte cycle CL (n = 34) New CL (n = ) Progesterone, ng/ml x mg c d c P =.7 P =. P =.34 P =. P =.34 P =. P =.4 P =. Dys from onset of -dy progrm Figure 4. Concentrtions of progesterone on dys,,, nd for cows treted with either 2 mg F 2α () on dys nd (2 2) or mg on dy ( ) in Exp. 3. Cows were clssified y concentrtions of progesterone on dy nd : () nestrus (< ng/ml on oth dys); (2) erly cycle ( ng/ml on oth dys); (3) lte cycle ( ng/ml on dy nd < ng/ml on dy ; nd (4) new CL (< ng/ml on dy nd ng/ml on dy )., Mens within tretment differed (P <.) mong cycle sttuses. 3