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Published byMargery May Modified over 9 years ago
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Level II Agricultural Business Operations
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Cow needs to calve to produce milk Need to calve regularly to maintain yield Infertile cows need to be replaced Fact 1: The average cow in Northern Ireland is culled after completing just 3.5 lactations Fact 2:Approximately 30% of cows are culled for infertility
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Gestation Length: Interval from conception to calving Average:280 days Range:270-290 days Oestrous Cycle Length: Interval from one heat to another Average:21 days Range: 18-24 days Calving Index: Average interval between successive calvings for herd Average:420 days (from milk recording) Range:360-500 days+
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Infertility Increased financial loss } semen usage intervention treatments spread of calving cull rates longevity Poor longevity replacement costs Implications of Infertility
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Fertility is influenced by a number of factors: Fertility Has Been Declining... Why? Is infertility due to larger herds and/or poor nutrition of the high-yielding cow? Feeding/Management By breeding for increased milk production, have we bred less fertile cows? Breeding/Genetics
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Calving index prone to error/ misinterpretation i.e. does not include cows culled for infertility HerdCalving index (days ) A370 B390 Which herd has the best fertility... ? Culled not-in-calf (%) 15 5 Assessment of Dairy Cow Fertility
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The True Cost of Infertility Herd A (365 days; 15%) Calving Index Cost5 days @ £3/cow/day x 100 cows = £1,500 Replacement cost15 cows @ £900/cow =£13,500 TOTAL = £15,000 Herd B (390 days; 5%) Calving Index Cost25 days @ £3/cow/day x 100 cows = £7,500 Replacement cost5 cows @ £900/cow =£4,500 TOTAL = £12,000 Herds with lower calving intervals don’t necessarily have a lower infertility cost !
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Calving Pregnancy – 280 days 365 days 85 days Breeding/Conception Pregnancy – 280 days Breeding Conception Calving 405 days 125 days
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AI Bull Greater genetic progress Multiple bulls - match bulls to individual cows Heat detection difficult and time consuming AI technique – does it affect your herd conception rates? How important are fertility and genetics in your herd? System – Are you high or low yielding? Calving pattern – is this important? Genetic progress – is this important? AI or Natural Service... ? Natural Service by Dairy Bull: Saves time in heat detection Conception rates – potentially better Bull fertility – problems? Genetic progress limited Bull may favour some cows Danger – especially indoors
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Standing to be mounted
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Chin-restingHead mounting SniffingLip-curling
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Restlessness/Bellowing CajolingSoliciting Licking other cows Hair loss/dirt marks Not standing to be mounted Secondary Signs of Heat - Less Important Signs
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Factors Affecting Heat Stage of oestrous cycle Number of cows in heat Presence of bull Housing – floor surface, layout, stocking density Stress - noise, change of routine Lameness and disease Nutrition – negative energy balance Weather & ground conditions at grass
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Knowledge of signs of heat Duration of observation ◦ Minimum of 15 minutes/observation Timing of observation ◦ Minimum of three observations/day ◦ Observe when cows aren’t being disturbed ◦ Activity greatest late night/early morning Heat detection aids Cow identification Use of records
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To optimise your heat detection rate requires: Awareness of the secondary signs of heat and their relative importance Factors that affect a cows expression of heat Management factors which affect your observation of heat Improved heat detection has more effect in improving your overall herd fertility than any other factor Heat Detection - Summary
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1.Herd records Paper records, Breeding boards, Computers 2.Teaser bull 3.Mount detectors: Tailpaint, Pressure strips 4.Movement detectors: Pedometers, Neck collars Heat Detection Aids
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Effective use of herd records is one of the most beneficial ways to improve herd fertility Requires clear and unique cow identification Good records allow easy identification of non-cycling cows and repeat breeding cows Records can be used to anticipate heats Simple paper-based herd recording systems are inexpensive and effective Computer software often most effective, but expensive and operators may require training Heat Detection Aids: 1) Herd Records
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Pocket diary Calendar 21-day diary Heat Detection Aids: 1) Herd Records – Paper Records
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Cow ID Date Calved Calving Code (1 = No assistance; 5 = Caesarean) Calf Number Prebreeding Heats – Heat 1, Heat 2 Service Record – Date and Bull of Service 1, Service 2, etc Pregnancy Diagnosis – Date, Result Drying off – Date for drying off, Body Condition Score Due Date Heat Detection Aids: 1) Herd Records – Paper Records
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Heat Detection Aids: 1) Herd Records – Breeding Boards
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Heat Detection Aids: 1) Herd Records – Computer Action List
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Heat Detection Aids: 2) Teaser Bull Bull calf that has been vasectomised (rather than castrated) Can still mount cow successfully but ability to fertilise removed Identifies cows on heat However, he is a bull - can still be dangerous Advisable to have a new calf vasectomised each year
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Cheap and effective, especially at grass Specially formulated paints or bright coloured emulsion paint Different colours can be used 10 cm wide strip on cow tailhead For use on whole herd or on cows not yet pregnant Cows should be checked at each milking Heat Detection Aids: 3) Mount Detectors - Tailpaint
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Heat Detection Aids: 3) Mount Detectors – Pressure Strips Pressure sensitive device glued onto tail head Pressure from mounting animal turns detector from white to red Built-in timing mechanism requires ~3 seconds pressure to activate e.g.Kamar Bovine Beacon
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Step counting sensor (pedometer) worn on leg or movement sensor on neck collar Both devices measure activity of each cow Assists detection of oestrus and health ailments Available as stand alone system or as part of modern milking parlour system e.g.Heat Time, DairyMaster, GEA, DeLaval, Fullwood Heat Detection Aids: 4) Movement Detectors
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Heat detection aids facilitate better heat detection Good record keeping: allows anticipation of heats Sophisticated technological aids are being developed but simpler and cheaper aids may be just as effective Heat detection aids should not be a replacement for time spent on heat detection ! Heat Detection Aids - Summary
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Voluntary Waiting Period: - Period after calving during which cows are not normally served - Typically 42 days but can be higher in higher yielding herds or lower in spring calving herds Conception Rate: -Proportion of services that lead to conception or subsequent calving (calving rate)
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Factors Affecting Conception Rate - AI related factors Flask management Sire choice Bull fertility (AI or natural) Semen handling AI technique
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Factors Affecting Conception Rate - Management Factors Cow handling facilities Timing of AI (from onset of heat) Accuracy of heat detection Nutrition Interval from calving Disease status (BVD, Lepto, etc) Lameness
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Practical Ways to Improve Fertility Herd Health Status: -Test for BVD, Lepto and Salmonella and vaccinate if necessary Sire Selection: -Select bulls with a positive fertility score When to Breed: -Don’t serve cows while they are still losing weight Number of Matings: -Inseminate cows twice to dairy AI -Subsequent services should be to a beef breed
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Good fertility management is essential Extended calving intervals are estimated to cost around £3/cow/day Aim to improve fertility through better: a)Heat detection – good herd records essential; use heat detection aids if necessary b)Conception rates – good AI technique and herd management Observe, record and monitor performance
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