Sow Reproduction and Seasonal Infertility Darlington Pig Discussion Group 13 th March 2014 Richard Bull
Richard Bull Taurus Concepts Ltd
Sow Reproduction
Endogenous Hormones Gland Hormone Function Hypothalamus Anterior Pituitary Gonadotropin Releasing Hormone (GnRH) Follicle-stimulatiing hormone FSH and LH release Follicle growth Ovaries Luteinising hormone Oestogens Progesterone Inhibin Relaxin Selection of follicles Release of oestrogen from ovaries Ovulation Formation & maintenance of corpus luteum (CL) Oestrus behaviour Maintenance of gestation (neg feedback to hypothalamus) Inhibition of FSH release Expansion of pelvis Dilation of cervix Uterus PGF2α Regression of CL Parturition
Reproductive Cycle Farrowing to farrowing Gestation = 115 days Lactation = 26 days Weaning to 1 st Service = 7 days Total = 148 days Annually = 2.47 cycles/year Any extra days are empty days
The Oestrous Cycle Average of 21 days ovulation to ovulation Variable 18 24 days Start day 1 at ovulation Two Phases Luteal Phase Follicular Phase
Luteal Phase 14 days in length Eggs released from ovary (LH dependant) Formation of corpus luteum (CL) (LH dependant) Progesterone inhibits GnRH If not pregnant Uterus releases PGF2a by day 14-16 Regression of CL (luteolysis) to corpus albicans Ceases to produce progesterone - GnRH production re-starts from hypothalamus Stimulates FSH and LH release from pituitary gland Follicular phase commences
Follicular Phase Starts day 15 GnRH production absence of progesterone FSH & LH Recruitment, growth and selection of ovarian follicles All follicles grow independent of FSH to a given size <1mm dia Follicles recruited for growth at start of follicular phase and grow to 3-4mm dia. This is FSH dependant Selection of follicles for maturation. Growth to 7mm-9mm dia. This is LH and FSH dependant Increase in LH pulses Oestrogen production Onset of heat Surge in LH at day 21 gives rise to ovulation
Hypothalamic-Pituitary-Ovary Axis LH Surge PGF2α Uterus
Sow Oestrous Cycle
Ovulation Ovulation is spontaneous Occurs at 30 to 40 hours post onset of oestrus behaviour Average ovulation time is 6 9 hours 10 to 30 ovocytes are released from the ovary Corpus luteum is established
Gestation The cycle is stopped during pregnancy Production of progesterone by corpora lutea maintains negative feedback on GnRH At farrowing a new cycle starts.. No more progesterone Corpora lutea destroyed by action of PGF2α
Inhibition during lactation Lactation Piglets Stimuli Milk Production Hypothalamus GnRH Inhibition Prolactin & oxytocin Stimulation Lack of Energy Pituitary gland Ovulation FSH & LH Inhibition Inhibition of metabolic mediators (Insulin, IGF-1) LH Days Farrowing Weaning Inhibition of follicles <6mm Growth of pre-ovulatory follicles
Uterine involution Process of the uterus returning to normal non pregnant state. Pregnancy = 115 days Uterus at the end weighs 12 times normal Length 4 metres 3 weeks to recover fecundity Maximum decrease of uterine weight occurs in first 8 days post partum From 3kg to 1kg Recovery of endometrium 14 21 days post partum Up to 28 days for complete recovery
Seasonal Infertility
What is Seasonal Infertility? A reduction in the sows ability to either demonstrate oestrus behaviour or produce a successful litter from a matings during the summer months.
Seasonal Infertility Why The pig is naturally not polyoestrous Domestication has imposed this requirement Evidence suggests the pig to be a short day breeder Photoperiod or day length Temperature Is this more related to nutrition? Remember the other factors - Melatonin Nature is taking over!
The light and dark regulation of the biological clock (suprachiasmatic nucleus), pineal melatonin production, and seasonal reproduction in photoperiodic mammals. Reiter R J et al. Biol Reprod 2009;81:445-456 2009 by Society for the Study of Reproduction
What Happens? Increase in weaning to service interval Reduced farrowing rate % Reduced numbers born Increased regular and irregular returns Increased numbers of anoestrous gilts
Production Data 2009-2012 Inc. 2009-2012 Averages Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Totals Number of serves 55620 54731 58446 55713 58388 56546 57244 59749 56674 59776 57932 52619 683438 Return Serves % 12.60 12.025 11.175 11.2 10.7 11.45 12.075 12.15 13.325 13.275 11.4 11.475 11.90 Farrow % 81.325 81.7 81.6 82.2 81.3 80.35 78.825 78.15 80.025 82.35 84.2 84.05 81.34 Farrowing 45190 42789 45972 45972 45972 44308 46532 45499 44393 45304 41928 42153 536012 Live born/lit 11.725 11.775 11.825 11.875 11.85 11.925 11.975 11.95 11.875 11.75 11.8 11.75 11.84 Mummified/Lit 0.35 0.35 0.35 0.375 0.4 0.375 0.375 0.375 0.4 0.425 0.375 0.375 0.38 Born dead/lit 0.8 0.775 0.725 0.725 0.725 0.7 0.725 0.7 0.7 0.7 0.725 0.775 0.73 Total Weanings 41747 41128 46078 46078 46078 44192 45040 45285 46009 42865 42238 44162 530900 Pigs weaned/lit 10.175 10.275 10.325 10.475 10.5 10.55 10.55 10.525 10.5 10.45 10.4 10.375 10.43 %Pre-w mortality 12.85 12.5 12.15 11.7 11.375 11.225 11.675 11.775 11.925 11.9 11.825 12.025 11.91 Animals removed 9552 9664 10685 10685 10685 9870 10026 10271 10358 10545 10593 8002 120936 Removed Dead 602 547 667 667 667 638 692 536 626 645 549 545 615.08 Average Age @ Culling 4.55 4.55 4.475 4.625 4.5 4.533333 4.45 4.3 4.4 4.375 4.425 4.325 4.46 Preg. days/lit 115.625 115.675 115.675 115.675 115.7 115.625 115.675 115.65 115.625 115.625 115.625 115.65 115.65 Suckl. days/lit 26 26.05 26.15 26.325 26.275 26.125 26.175 26.3 26.45 26.525 26.425 26.425 26.27 Non-prod. days/lit 17.125 16.475 16.325 15.975 15.975 16.175 16.975 17.725 17.975 16.825 14.925 13.5 16.33 Lit/Sow/Year 2.3 2.3075 2.31 2.31 2.31 2.31 2.3 2.285 2.2825 2.2975 2.325 2.3475 2.31 Pigs weaned/sow/yr 23.3325 23.7075 23.8225 24.165 24.305 24.355 24.265 24.115 23.9975 23.98 24.1775 24.3725 24.05 Source: adapted from Agrosoft
Farrowing Rate % 2009-2012 inclusive Farrowing Rate % 85 84 83 82 81 80 79 78 77 76 Farrowing Rate % 75 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Source: adapted from Agrosoft
Average Return Serve % 2009-2012 inclusive 13.5 13 12.5 Return % 12 11.5 ` Return Serves % 11 10.5 10 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Source: adapted from Agrosoft
Average Farrowings 2009-2012 inclusive Farrowings 47000 46000 45000 44000 43000 42000 41000 40000 Farrowings Poly. (Farrowings) 39000 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months Source: adapted from Agrosoft
Average Born Alive 2009-2012 inclusive 12 11.95 11.9 No Born Alive 11.85 11.8 11.75 Live born/lit 11.7 11.65 11.6 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months Source: adapted from Agrosoft
Average Clean Pig Slaughterings 2009-2012 inclusive 680 660 Slaughterings (000 head) 640 620 600 580 Average 560 540 1 2 3 4 5 6 7 8 9 10 11 12 13 4 Week Periods (Start Jan) Source: BPEX
DAPP EU Spec 2009-2012 165 160 155 Price (p/kg dead_ 150 145 140 2009 2010 2011 2012 Average 135 130 125 1 2 3 4 5 6 7 8 9 10 11 12 13 4 Week Period (Start Jan) Source: BPEX
What are the causes Multi-factorial Remain debatable Different at different times of the year? Early season reductions less noticeable Temperature related Feed Intake Semen quality (Natural & AI) Light intensity Overriding cause would appear to be photoperiod or day length Speed of day length change
Rate of Day Length Change
Spring Equinox 85 84 83 Farrowing Rate % 2009-2012 inclusive Autumn Equinox Farrowing Rate % 82 81 80 79 78 77 76 Farrowing Rate % 75 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Source: adapted from Agrosoft
Seasonal Infertility - Causes Day Length Light Intensity Temperature Nutrition Stress
Factors influencing fertility Season Photoperiod Temperature Boar contact Length of lactation Feed Litter size Suckling Milk production Genotype & Parity HPO Axis Nutritional balance, Insulin, IGF-1 Ovarian follicles Oestrus and ovulation
Are all Parities affected? Yes However Parity 2 more so Gilts and most productive parities less affected Parity 6 onwards overall fertility starts to fall including and season affects them more
Farrowing Rate % 2009-2012 inclusive Farrowing Rate % 88 86 84 82 80 78 76 74 72 70 Parity 1 Parity 2 Parity 3 Parity 4 Parity 5 68 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Source: adapted from Agrosoft
What does it cost? Depends on how significant it is. By limiting the effects the producer will Increase PPSY Achieve consistent and regular pig flow Optimise pig price Increase income Producers must recognise the effect and act to limit the production shortfalls. Model performance
Performance Data by Month Maximum Minimum Average Farrowing Index 2.35 2.28 2.31 Farrowing Rate % 84.20 78.15 81.34 Total Born/Litter 13.08 12.88 12.95 Born Alive/Litter 11.98 11.73 11.84 Pre-weaning Mortality % 12.85 11.23 11.91 Weaning Age 26.53 26.00 26.27 Source: adapted from Agrosoft
Five Year Returnss
What can be done! Interrogate records Identify problem areas Increase gilts available for service during critical times Reduce culling at critical times Increase service targets at critical times All of above can cause difficulties on farm
What can be done! Ensure high lactation intakes in weeks prior to and through the predicted poor fertility period. Particularly young sows Feed high quality lactation diets Increase feed intake between weaning and service Feed a diet high in starch and sugars between weaning and service Provide shade in outdoor paddocks Under veterinary supervision consider gonadotrophin intervention Most important area if influence!!
What can be done! Consider using 16 hours lighting in the service area?
Min 16 hours light 360 lux in service area % herds p = 0.17
What can be done! Each farm is different with different challenges
Take home messages ACT NOW PLAN AHEAD
Thank you for your attention