Improving reproduction in NZ dairy herds Scott McDougall, Tom Brownlie, Melvin de Boer, Chris Compton Cognosco, Anexa Animal Health, Morrinsville, New Zealand smcdoug@ahc.co.nz
Herd Fertility Is like a cake Herd Management areas - 8 ingredients Calving Pattern Heifer Mgt. Body condition & nutrition Heat Detection Genetics & AB Practices Bull Mgt. Cow Health Dealing with noncyclers
Key areas of fertility management Varies among farms & often multifactorial So whole farms systems approach InCalf used in 10-15% of herds nationally? However for many farms the key issues are Poor heifer growth Poor calving spread Low BCS Peripartum and uterine disease Non cycling cows
So what are approaches? Specific interventions include: Non cycler diagnosis & treatment Endometritis diagnosis & treatment Managing calving patterns Mating length Culling Synchrony Induction
Non cycling cows Not detected in oestrus before mating start date (or day -10) Associated with Younger cows Friesians Late calving Disease around calving Low BCS
Cumulative % pregnant by status before breeding start P<0.001 AA vs. others; Data from McDougall & Compton JDSc 2005
Economic impact ($NZ/400 cows) Actual (%) Difference (%) 6 week 6 week Group $/400 cows InCalf MT InCalf MT AA -20,475 53.4 15.5 10.1-3.6 Cycler 0 63.4 11.8 At NZ national level = $40 million loss/annum
How to deal with ND0/AA cows?
Management of NDO/AA cows Prevention Genetics Breed Dry off decisions Prepartum nutritional management Macro & micro BCS effects Milking frequency Peripartum cow disease management Cure Bull effects Once a day milking Split off Hormonal
Breed/genetics approaches Breed 10% reduction in NDO by switching breeds Major farm systems effects Genetics h 2 of calving to 1 st ovulation (P4) ~ 15-30% In NZ breeding objectives but using PSM-1 st breeding (h 2 = 6%; Grosshans et al 1997) Slow (10 years +) & expensive? Use of clinical phenotypes (scan/palpation?) as proxy for P4 Specific SNP s?
Separate grazing and P4 response Control Split P4+ ODB Split+ P4+ ODB Number of cows 172 177 168 159 Inseminated by 28 days 55% 46% 94%* 87%* Conceived to 1st AB 40% 33% 36% 27%* Pregnant by 28 days 26% 19%* 42%* 31% * P<0.05 vs. control; Clark et al 1999; NZSAP 59:55-57
Treating non cyclers with once a day milking and/or P4+ODB Con OAD P4+ ODB P4+ ODB+ OAD No. cows 110 106 107 94 Submission D21 66% 77% 94% 98% Con rate to 1 st serve 54% 47% 47% 34% Preg 3 wks 38% 42% 53% 45% PSM-con (days) 20 (±2) 18 (±2) 12 (±2) 14 (±2) Empty 12% 14% 5% 12% Milk yield difference (TAD-OAD) = 0.27 kg MS/cow/day Main effect of P4+ODB for Sub D21 + PSM-Con p<0.05 for P4+ODB; Rhodes et al 1998; NZSAP
Bull effects? Beef heifers and cows = +ve effects (Berardinelli et al 2008) No bull Bull P-value No. heifers 67 94 % cycling at PSM-7 31.3 85.1 <0.001 % in oestrus after PG 49.3 52.1 0.86 % bred to timed AI 67.2 62.8 0.67 % con rate at time AI 35.6 57.6 <0.05 % preg rate 51.5 66.3 <0.05
Hormonal treatment of NDO/AA cows Combination of GPG ( Ovsynch ) + progesterone increase pregnancy rates over GPG alone or no treatment This effect is consistent across CL+ and CL-ve NDO cows 1 st service conception rate NSD between control and treated cows Economic
McDougall JDSc 2010
Mean (SE) interval (days) from start of breeding to conception CL status p<0.001; Group p=0.03; group by CL status p>0.1 Columns within CL status with different superscripts differ at p<0.05
Diagnosing and treating cows with uterine or ovarian disease Metritis Endometritis Pyometra Ovarian cysts
Diagnosis Metritis <21 days after calving Systemically ill (hot, off feed, smelly & bloody discharge) Endometritis >20 days calved Usually not systemically ill Purulent material in vagina &/or uterus
Does peripartum disease matter? McDougall 2001 NZ Vet J 49: 60-67
Risk factors for uterine infection Difficult calving Bull calves Caesarean section Heifers Twins Retained placenta Displaced abomasum Vulval angle High milk protein % Inadequate transition BCS Ca Mg BOH, NEFA Albumin GDH, AST
= High PMN% = Low PMN% Burke et al 2011
Diagnosis of uterine infection Metricheck? Vaginoscopy? Cytology? Visual assessment? Palpation? Scanning? Bacteriology? Histopathology?
Score 1 Score 4 Score 2 Score 3 Score 5 McDougall et al 2007 ARS
Frequency of score McDougall et al 2007 ARS
Median interval (d) to conception * * * * McDougall et al 2007 ARS
% of cows with uterine infections by days calved Sheldon & Dobson Theriogenology 2004
vs. PGF2 Antibiotics
Intrauterine antibiotic treatment of cows with a history of RFM no. cases CIDR'ed (%) Sub D28 (%) Con S1 (%) Preg D28 (%) Preg D56 (%) Days to conceive MT (%) Con 132 15.2 87.9 40.9 45.5 78.4 33 9.1 Met 136 16.9 94.9 50.0 57.4 86.7 20 7.4 McDougall NZVJ 2001 Diff P 1.8 7.0 9.1 11.9 ** 8.3 ** -13 * -1.7
Effect of antibiotic treatment of endometritis (metricheck +ve) cows (Runciman et al 2009) RR(6 wk) = 1.50 (95%CI = 1.10-2.06; RR(21wk) = 1.15 (95%CI =0.98-1.36)
Effect of PG at days 35 and 49 after calving on reproductive performance No effect of PG in High or Low risk of uterine disease, No effect of P4 status (Dubuc et al 2011 JDS)
Manipulating calving patterns Calving pattern important determinant of % NDO, conception rate, 6-week in-calf rate, MT rate Pattern can be manipulated by Synchronisation and/or early mating of the heifers Synchrony of cows Use of short gestation bulls Shortening the duration of the breeding period Strategic culling of late calvers Induction of parturition
Heifer synchrony Calve heifers ahead of herds: more days before start of breeding (fewer NDO heifers) AIso shorten generation interval
Conception rate to first Service (AB) First service Treatment Group conception rate (%) Double-PG 119/248 ab (48) GPG + P4 180/383 a (47) Cosynch + P4 213/374 b (57)
Pregnancy rate to first Service (AB) (i.e. # preg/all synchronised) Treatment Group In-calf to AB (%) Double-PG 119/380 a (31) GPG + P4 180/383 b (47) Cosynch + P4 213/374 c (57)
Pregnancy rates
Treatment Group Double-PG Difference in days in milk 0 GPG + P4 3.9 Cosynch 6.4
Cow synchrony: why wait PG systems Red tail paint PG Greens Blue tail paint PG Yellows Green tail paint Treat noncyclers -35-21 -14-9 Yellow tail paint -7-2 0 (PSM) +5
Progesterone-based whole-herd synchrony systems with AI on detection Control: AI on detection PG AI (on detection) -3-2 0 GnRH (1) 8 days Synchronized: 7 days (2) -10-9 Days from start of breeding Xu and Burton, 2000 JDS 83:471-6
Synchrony results (%) of cows 8D P4 7D P4 Con Synch Con No. 512 515 Sub d6 33 93 504 32 509 92 Con S1 63 57 63 65 Preg AI* 82 86 80 85 MT 5 4 5 5 Days to con 22 14 21 14 * 5-7 weeks; Xu and Burton, 2000 JDS 83:471-6 Synch P * * *
Induction of parturition Cows due to calve late in calving periods can be induced to calve earlier Use analogue of the normal signal for calving (corticosteriods) Managed under a memorandum of understanding between Vets Processors Farmer organisations (DairyNZ, Fed Farmers)
Specific cow & herd requirements Stated industry goal is to reduce use of induction Targets set (maximum % of cows within a herd): 15% 8% 4%? in 2010/11 in 2011/12 in 2012/13 in 2013/14
Technically induction works i.e. calving date advanced by 6 to 8 weeks for the majority of cows More days in milk, longer interval to start of breeding = fewer NDO cows Potential issues Immunosupressant: increased risk of disease? Calves non-viable: euthanasia issues
NZ breeding programmes Examine Not detected in oestrus cows BCS Tailpaint BCS, nutrition & trace elements Apply tailpaint all cows Examine cows with GnRH PG peripartum disease Pick-up bulls P4 checked Calving (80 d) -85-35 STAI Pregnancy diagnosis (manual or US) AI (28-42 d) -10-2 -1 Planned start of calving: PSC BCS Review performance Modify as required 0=PSM* *Planned start of mating Bull (50-80 d ) 77-84 ~35-56 days after bull removal
Conclusions Reproductive performance in NZ is declining Introduction of InCalf may help: focus on prevention & systems approach Usually multifactorial approach required Common issues include poor calving spread, non cycling cows, peripartum disease, low BCS
Not detected in oestrus cows are a significant cost to industry Multiple approaches to prevention / treatment Hormonal treatment remain most consistent/effective Ovsynch + P4 most effective and costeffective
Preventative strategies remain unproven Nutritional strategies for pasture fed cattle unclear Postpartum anovulatory interval has higher heritability than other reproductive measures Possible basis for selection Cost of phenotype? Use of proxies such as submission rate, CL status at vet exam?
Peripartum disease increases risk of uterine infection/inflammation which in turn depresses fertility The metricheck device has improved ability to detected infected cows Intrauterine antibiotics are the most effective current treatment Induction is being phased out
Thank you Questions?