Prevalence and Risk Factors for Postpartum Anovulation in Dairy Cows Robert Walsh November 30, 2006

Outline Resumption of Ovarian Activity –Identification of at Risk cows –Cow-level risk factors –Herd-level risk factors Questions

Outline Resumption of Ovarian Activity

Calving Ovulation DIM Follicle diameter (mm) Resumption of Ovarian Activity All follicles present at birth Follicle development divided into 3 stages Stage SizeDuration Recruitment< 0.13mmbirth - Slow phase0.16 – 3 mm10 – 40 days Fast phase> 4 mm days (Lussier et al. 1987)

Calving Ovulation DIM Follicle diameter (mm) Resumption of Ovarian Activity Atresia or ovulation IGF-1, IGFBP, E 2, …. Deviation Luteinizing Hormone (LH) Emergence Follicle Stimulating Hormone (FSH)

Calving Ovulation DIM Follicle diameter (mm) Resumption of Ovarian Activity 33.8 days (1106 Lactations; Petersson et al. 2005) 27.4 days (>1200 Records; Royal et al. 2004) 28.7 ± 14.6 days (2503 Lactations, Lamming and Darwash 1998) 29 days Control line vs. 43 days Select (Lucy et al. 2001) 43 days First Estrus (1398 Lactations, Thatcher and Wilcox, 1973)

Resumption of Ovarian Activity Reference Location DIMDOV1ALL Lopez et al Wisconsin % Cerri et al. 2004California6525.7% Moreira et al. 2001Florida6323% Opsomer et al Belgium %49% Lamming and Darwash 1998 England 10.9% 38% Shrestha et al Japan24.1%57% Archbald et al. 1990Florida3030% McDougal and Compton 2005NZ20.9% Thatcher and Wilcox 1973 Florida6025.9% (Estrus)

Days In Milk Follicle diameter (mm) (Wiltbank et al. 2002) Anovulation Follicular Growth to Deviation Consecutive waves of follicle growth initiated by FSH Insufficient LH to support deviation Communication failure between ovary and hypothalamus

Days In Milk Follicle diameter (mm) (Wiltbank et al. 2002) Anovulation Follicles Larger than Ovulatory Size LH release supports deviation Elevated E 2 concentration Failure of ovulation The presence of large follicles does not preclude Normal ovarian activity and function

Outline Resumption of Ovarian Activity –Identification of at Risk cows

Objectives Determine prevalence of anovulation Assess consequences of anovulation Identify cow-level risk factors –herd-level risk factors

Observational Protocol Milk Ketotest ™ BCS HH visit BCS, Lameness Milk P 4 Collect Reproduction and Culling Data Record peripartum disease Data presented from 1341 cows Anestrus Both samples <1ng/ml Calving

Descriptive Data Tiestall Freestall Herds Cows Herds Cows Herd Size < 100 cows > 100 cows Milk Frequency 2 Times/day Times/day TAI First Service > 90 % to 50% Rumensin CRC Premix Both

Study Population Enrolled 20 herds (lost 2) –Total calving 2645 –Culled prior to 52 DIM 277 –Total eligible2368 –Two Milk Samples –Met Inclusion criteria1341 (56.7%) Herd specific inclusion ranged 33 – 90% Disease under-reported in cows not sampled No significant difference in parity distribution, first milk projection, days dry between included and excluded cows Excluded cows more likely culled (P < 0.001) 1 Excluded if milk sample protocol violated or use of hormones

Cow Level Prevalence of Anovulation 19.5% (95% CI 17.4 – 21.7%)

VWP d Calving No Estrus Activity Ovarian Activity ?? Impact of Anovulation 1 in 5 cows Herd Repro Management Heat Detection Timed Insemination protocols

Time to First Insemination Herd Repro ProgramFactor AIHR P 95% CI HeatAnovular80 b 0.7 < to 0.8 Detection 1 Cycling 72 a Referent TimedAnovular78 ab to 1.2 AI 2 Cycling76 b Referent Multiparous to 0.9 Retained Placenta0.75 < to Insemination at Observed Estrus in >50% of herd (12 herds 79% of cows) 2 Timed Insemination in > 90% of herd (6 herds, 21% of cows)

Probability of Pregnancy after First Insemination Herd Repro ProgramFactor FSCROR P 95% CI HeatAnovular20.3 b to 0.6 Detection 1 Cycling 30.5 a Referent TimedAnovular29.7 ab to 1.2 AI 2 Cycling35.9 a Referent Multiparous to Insemination at Observed Estrus in >50% of herd (12 herds 79% of cows) 2 Timed Insemination in > 90% of herd (6 herds, 21% of cows)

Time to Pregnancy Time Adjusted HR Adjusted HR = HR*TVC ln(t)

Diagnosis of Anovulation Rectal Palpation 1 (2 palpations 14-days apart) Sensitivity 65.4% Specificity 68.6% Positive Predictive value 31.9% 1 gold standard circulating progesterone

Diagnosis of Anovulation using Pedometry (HDR ~ 60%) Sensitivity 83.0% Specificity 68.0% Positive Predictive value 34.0%

Diagnosis of Anovulation Assumption 100 cows, True Prevalence of 20% 1 Walsh et al. (Unpublished) 2 Sprecher et al. 1989; Theriogenology 3 McDougal and Rhodes, 1999; NZVJ (Apparently Anestrus cows) 4 Core et al. (Unpublished)

Outline Resumption of Ovarian Activity –Identification of at Risk cows –Cow-level risk factors

Univariable Risk Factor Analysis Controlling for fresh season (* P < 0.05; ** P < 0.01; *** P < 0.001)

Final Risk Factor Model (* P < 0.05; ** P < 0.01; *** P < 0.001)

Prevalence of anovulation by Parity Parity is an inconsistent risk factor for anovulation

Lameness 238 Animals, 11% DOV Lameness (Median day of diagnosis = 15 DIM) –42% Moderately Lame –17% Lame Relative to animals never classified as lame controlling for calving season, lactation, ketotsis*and Milk Production (305ME)* –Moderate Lameness 2.14 odds of DOV (95%CI = 0.7, 6.14) –Lame 3.5 increased odds of DOV (95% CI = 1.0, 12.7) Calving Lameness Score (1-5) Milk P4 Garbarino et al. 2004

Lameness and Reproductive Performance 65 Cases, 130 Controls Controlling for parity, calving season, and milk yeild (305ME) –Non-lame cows 4.22 times more likely to conceive at first service (95% CI 1.59, 11.2) –Lame cows 2.63 times more likely to have an occurrence of an ovarian cyst Using Survival analysis –Lame cows HR 0.43 (95% CI 0.28, 0.66) Melendez et al. 2003

Body condition Loss Lopez-Gatius et al. Theriogenology cows from 11 studies Relative to BCS <2.5 at parturition + 6 DOPN >3.5 at parturition – 6 DOPN Relative to BCS change <0.5 units between parturition and first AI Loss > DOPN Not significant in all studies Ruegg et al Domecq et al. 1999

Milk Production StudyMilk Measure Delayed Ovulation Opsomer et al d & 305d FCMns Shrestha et al d FCMns Santos et al. 2004Proj 305 ME 0.21(0.05 to 0.98) high vs. Med Time to Pregnancy Gröhn and Rajala-Schultz d MilkHR0.92 (highest vs. lowest)

Outline Resumption of Ovarian Activity –Identification of at Risk cows –Cow-level risk factors

Cow Level Prevalence of Subclinical Ketosis Week % (95% CI 23.5 to 28.9 %)

Energy Balance and DOV 54 Multiparous HF cows calculated energy balance ItemERLRNR Number25 (46%)14 (26%)15 (28%) 4% FCM (kg/d) DMI(kg/d) Day to Ovulation Days Open Calving Progesterone Profile ER LR NR Staples et al. 1990

Estimating Energy Status Significant correlation between ketone body concentration and CLA (Reist et al. 2000) Milk Acetone week 3-6 not associated with FSCR (Plym-Forshell, 1991) Increased DOPN, Increased culling risk (Cook et al. 2000) 1400  mol/ml  HBA cutpoint used for disease status

Impact of subclinical ketosis on the probability of pregnancy at first service and time to pregnancy Objectives Is SCK early in lactation associated with the probability of pregnancy at first insemination? Which week postpartum has the most impact? Does the duration of SCK impact probability of pregnancy at first insemination or time to pregnancy ?

Impact of subclinical ketosis on the probability of pregnancy at first service and time to pregnancy Serum Sample Store samples and analyze for  HBA BCS Observe for estrus and breed PD Calving BCS  25 Herds ( cows)  1010 cows  Exclusion criteria  806 records for analysis  Rumensin CRC study (Duffield et al. 1999)

Distribution of serum BHBA 16% week 1 ( 132/806 cows ) 19% Week 2 ( 152/806 cows )

Mean Serum BHBA Sorted by Pregnancy Diagnosis to First Insemination

Investigation of Cutpoints

Impact of Subclinical Ketosis in the Second Week Postpartum on the Probability of Pregnancy at First Insemination Probability of Pregnancy Week 2 serum BHBA concentration (mmol/L)

Effect of Prolonged Elevation of Serum BHBA on the Probability of Pregnancy at First Insemination Number of Weeks Above BHBA Cutpoint Probability of Pregnancy (%) OR = 0.83 P = 0.2 OR = 0.47 P = 0.003

Impact of duration of subclinical ketosis on time to pregnancy Survival Function (Proportion Not Pregnant) Days in Milk Not Ketotic Ketotic week 1 or week 2 Ketotic both week 1 and 2 Time Adjusted HR Adjusted HR = HR*TVC ln(t) Median time to Pregnancy

Cow-level Summary Diagnosis is problematic Calving history / periparturient disease Subclinical ketosis

Dry Period Length >77days vs. <63 days 2.9 times more likely to experience DOV (Opsomer et al. 2000) DD associated with increase risk of longer DOPN (Moss et al. 2002) (Gümen et al. 2005)

Milking Frequency 3X vs 2X majority of studies show no difference (Weiss et al. 2004; Barnes et al. 1990; Amos et al. 1985*) 3X vs 2X associated with 6d increase DOPN (Smith et al. 2002) 3X vs. 6X for 3 weeks increased DOPN (Bar- Peled et al. 1995)

Herd-Season Anovulation Prevalence 34 herd-seasons from 18 herds (Fall vs. Other) Linear regression of herd-level prevalence Relative to Tie-Stall barns the prevalence of anestrus ↓ 7.2% in 3-Row Freestalls (P = 0.1) ↓ 11.0 % in 2-Row Freestalls (P = 0.007) ↑ 2.1% for every 10% ↑in herd-season prevalence of SCK

Herd-Season Anovulation Prevalence Things to Consider –Stocking density –Number of ration or group changes –Dry period length

Questions ?

Acknowledgement Advisors Drs. Leblanc, Leslie, Duffield, Kelton and Walton Veterinarians Almonte, Bay of Quinte Veterinary Services, Embrun, Ferguson, Grenville-Dundas, Kirkton, Linwood, Listowel, Navan, New Hamburg, Tavistock AABP Research Assistantship