The he mpor mp tanc e of e Es E trous Detection on Re tion -ins insemination of Lac tating Dair Dair Cows

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1 The Importan nce of Estrous Detection on Re-insemination of Lactating Dairy Cows Ricardo C. Chebel

2 The Need for Time ely Re-Insemination of Lactating Dairy Cows Only ~ 35-45% of cows are pregnant after 1 st AI 21 d heat detection rate is often < 50% 100 open cows 50 re-inseminated within 21 d 25 re-inseminated within 42 d 13 re-inseminated within 63 d 12% of open cows not re-inseminated by 63 d after AI or 47.1% HDR Use of timed AI allows for 100% re-insemination within 3 to 10 d after non-pregnancy diagnosis

3 Are these the Resynchronization Most Common Strategies Used? TAI (AI on estrus) US/PD PD PGF TAI 0±3 32±3 Days after AI 39±3 41±3 42±3 TAI (AI on estrus) PD PGF TAI 0±3 39±3 Days after AI 46±3 48±3 49±3 THU MON MON WED THU MON WED THU

4 Current Resynchron nization Strategies Used Result in Low P/AI Average P/AI of cows resynchronized (published data) CA and WI (2003 to 2006) Wisconsin (2007 and 2009) AZ and CA (2008) = 30.7% = 27.5% = 24.6% P/AI of resynchronized vs. heat det tected cows (DC305 data) 537 lactating cows (80 lb/d) 1,016 lactating cows (90 lb/d) 3,379 lactating cows (82 lb/d) 5,778 lactating cows (70 lb/d) = 27 vs. 37% = 22 vs. 29% = 12 vs. 20% = 28 vs. 38% Unless heat detection accuracy is poor, P/AI of cows inseminated in estrus is expected to be 5 to 10% units better than current resynchronization strategies used

5 Where Resynchroni ization Strategies go Bad? Stage of the estrouss cycle at the start of resynchronization protocols and lack of synchrony at TAI KEYS to success: Control of follicular growth Control of luteal regression

6 Follicle Growth and Initiation of Timed AI 23% 96% 54% 77% Vasconceloss et al. (1999)

7 Initiation of the Ovsy ynch Protocol between Estrous Cycle d 1 and 4 (Metestrus) P Ovulation d 0 PGF 2a d 7 d 9 d 10 PGF 2a TAI Courtesy: WW Thatcher

8 Initiation of the Ovs synch Protocol after Estrous Cycle d 10 (La ate Diestrus/Proestrus) 8 6 P PGF 2a 0 d 0 d 7 d 9 d 10 PGF 2a TAI Courtesy: WW Thatcher

9 Initiation of the Ovsy ynch between Estrous Cycle d 5 and 9 (Early Diestrus) 8 Ovulation 6 4 P 4 2 PGF 2a 0 Ovulation d 0 d 7 PGF d 9 Courtesy: WW Thatcher

10 Effect of Ovulation to the 1 st and Synchrony of the Estrous Cycle on Pregnancy per AI P < 0.01 P < Ovulation + - Synchrony Chebel et al. (2006); Bruno et al. (2009)

11 Timing of Initiation of Resynch According to the Phase of the Estrous Cycle TAI Day of Estrus d d 29 Day 5 Day 6 Day 7 Day 8 Day 9

12 Factors Affecting the Pat ttern of Return to Estrus SYNCHRONY of the ESTROUS CYCLE 85% of cows truly synchronized with TAI protocols 0% of cows truly in estrus when nseminated based on estrus signs ABNORMAL ESTROUS CYCLE LENGTH 15% of cows with short luteal phase afte er first AI INCIDENCE OF EARLY EMBRYONIC LOSS 58% of cows with viable embryos 6 d after AI 40% P/AI 28 d after first AI 31% of cows with embryonic wastage from 6 to 28 d after AI 18% of cows with abnormal return to estrus ~50% of cows have abnormal pattern of return to estrus (< 20 d and > 24 d)

13 Cows Pattern of Return to Es strus of Lactating Dairy Cow ws Proportion re-inseminated 20 to 24 d after AI (DC305 data) 537 lactating cows (80 lb/d) 1,016 lactating cows (90 lb/ /d) 3,379 lactating cows (82 lb/ /d) 4,971 lactating cows (84 lb/ /d) 5,778 lactating cows (70 lb/ /d) = = = = = 57.6% 53% 40.4% 54.5% 52.4% 8,856 lactating cows (81 lb/ /d) = 55% 51.7% Days after AI

14 Timing of Initiation of Resynch According to the Phase of the Estrous Cycle TAI ~ 50% of cows: Day 20 to 24 d after AI of Estrus d d 29 Day 5 Day 6 Day 7 Day 8 Day 9

15 Starting the Resync chronization Protocol based on Interval from Previous AI Not surprising if ~ 50% of the cows start in Metestrus Late Diestrus/Proestrus

16 Timing of In nitiation of Resynchronizatio on Protocol and Ferti ility

17 Timing of Initiation of Resynchronization Pr rotocol and Fertility Start of Resynch No. of farms Number of cows P/AI, % References Overall Chebel et al., a Fricke et al., b b 161* 26.7 Sterry et al., * Silva et al., ~ 80% of cows at Metestrus and Proestrus

18 Study being conducted in 5 sites (500 cows/treatment) Effect of Timi ing of Start of Resynchroniza ation on P/AI P > x2 design: resynch start at 32 or 39 d after AI/ +CIDR or CIDR Percentag ge 20 R32 R39 Minnesota data analyzed: 10 Resynch start date effect on P/AI: R32 = 209 vs. R39 = Preg. 32d Preg. 66d Preg. loss Bilby et al., unpublished

19 How to Assure protocols Start that Timed AI at the Correct Stage of the Estrous Cycle?

20 Presynchronization Protocols to Increase P/AI after Timed AI Two injections of PGF 14 d apart and d before the start of the timed AI protocol Sequential injections of PGF and (G6G and Double Ovsynch) PGF only used in cows not inseminated and/or not pregnant Injection of at random stages of the estrous cycle and 6 to 10 d before the start of the timed AI Ovulation to at random stage of the EC is ~ 30-40%

21 Recent Res search on Resynchronizatio on of Lactating Dairy Cows

22 RES n=286 TAI 0 Presynchronizin ng the Resynch Prog gram PD 32 Ovsynch 31.1% 25.6% Days after TAI TAI PR 31 d 66 d PGF+RES n=312 > 65% in heat 2 to 6 d after PGF TAI TAI 0 PD 32 PGF d Day after the 2nd PGF2a 46 Days after TAI Ovsynch % 35.2% Silva et al. (2007)

23 Presynchronizatio on with or CIDR Treatment Two commercial dairies, one in CA (free stall) and one in AZ (dry lot) Cows eligible to be enrolled one week before pregnancy diagnosis (32 ± 3 DSLH) Blood samples and ultrasound at and PGF (n = 130/treatment) nt (Study Design) Pregnancy exams at 39 ± 3 d after AI in CA and AZ Dewey et al., 2009

24 Resynchroniza ation Protocols Presynchronization with or use of CIDR Enrollment AI PGF +TAI Control n = OP AI PGF +TAI GGPG n = OP AI PGF +TAI CIDR n = ewey et al., 2009 OP 38 ED/AI CIDR 45 48

25 Effect of Resynchroniza ation Protocol on Ovarian Responses and Pr regnancy per TAI P < 0.01 P < 0.01 P < 0.02 Multiple CL at 1 Ovulation to 1 Pregnancy per TAI

26 Effect of Resynchronizati ion Protocol on Pattern of Re-insemination of Lactating Dairy Cows 35 Proportion in estrus, % Contro GGPG CIDR 0 OP 0 AI 31 Enrollment PGF Overall AI in estrus +TAI

27 Effect of Resynchroniz zation Protocol on P/AI of ALL Cows Enrolle ed in the Study (CA) Interval of Re-AI Control GGPG CIDR P - value TAI 27.6 (246) 35.2 (233) 34.6 (211) 0.15 Enrollment to first to PGF Cows starting in Metestrus Cows starting in Proestrus Overall 30.1 (359) 35.3 (295) 32.8 (293) 0.37 Mendonça et al., 2009

28 Economics of Re esynchronization Proto ocols Abstract accepted 2009 ADSA

29 Economic Return Ove er Straight Forward Resynchr ronization Items simulated: heat detection rate, cost of replacement heifer, value of cull cow, and cost of day open Distribution for total economic gain per cow / GGPG/C24 Mean= Distribution for total economic gain per cow / CIDR/D24 Mean= % 90% 5% % 90% 5%

30 Early Resynchroniza ation with or without Presynchron nizing PGF +TAI EarlyGGPG n = 635 PGF +TAI EarlyResynch n = 637 PGF +TAI LateGGPG n = 736 PGF +TAI LateResynch n = 840 Days after AI ED/AI hebel and Bilby unpublished

31 Insemination Rate Acc cording to Treatment Percentage e not re-ai, % EarlyGGPG EarlyResynch LateGGPG LateResynch Days after Previous AI 31 38

32 Effect of Resynchroni ization on Percentage of Cows Submitted to TAI and on P/AI P < 0.01 P = 0.96 P < 0.01 P = 0.13 Cows receiving TAI Pregnancy per AI

33 Take Home Messages! Starting resynchronization 26 or 333 or 39 d after previous AI should not affect P/AI Starting resynchronization d after previous AI is likely to reduce P/AI Presynchronization with PGF 12 d before the start of the resynchronization increased P/AI but extended the re-ai interval in 12 d May be a good option for herds with EXCELLENT heat detection efficiency Presynchronization with improved P/AI when resynchronization started at 39 d after previous AI given on d 17 suppresses 55% of estrus and given on d 24 or 31 suppresses ~ 30% of estrus CIDR during the resynchronization increased P/AI CIDR treatment from 32 to 39 d after AI reduced estrus in 10%

34 Take Home Messages! New resynchronization strategies improve P/AI in 7 to 9% units Re-inseminating cows in estrus usually results in P/AI 5 to 10% units greater than resynchronization We may implement new resynchronization protocols but we should NOT recommend 100% TAI, unless heat detection accuracy is terrible or there are no means to do heat detection

35 THANK YOU! Ricardo C. Chebel Department of Veterinary Population Medicine College of Veterinary Medicine University of Minnesota