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18 Cards in this Set
- Front
- Back
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What is the aim of an efficient beef suckler herd? |
To calve the herd over a short season (9-12 weeks) at the same time each year and wean one calf/cow. |
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What are 2 main components of a compact calving pattern? |
1) Even batches of calves to rear *Easy management of calves and efficient feeding of calves. 2) Cows at same stage of pregnancy and lactation *Efficient feeding of cows and efficient supervision at calving. *Fewer cow/calf deaths. Easy calvings cause less stress. Cows in correct BCS. Fewer difficult calvings. Calves of optimum birthweight. Good milk supply. -->Healthy calves with a high potential for growth -->Fertile cows for re-breeding |
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How can a compact calving period be achieved? (4) |
1) Have fertile cows, cycling at the start of the breeding period 2) Have a good replacement heifer breeding policy 3) Have fertile bulls run with cows for a restricted breeding period (9-10w) 4) Avoid introducing infectious infertility dz's |
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What is the key to beef cow fertility? |
Nutritional management *Need good BCS and energy plane. |
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What must be considered when calculating winter rations for beef cows? (3) |
1) Maintenance 2) Pregnancy 3) Lactation |
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What steps can be taken to maximize cow fertility? (9) |
1) BCS at calving directly related to post-calving anoestrus period/fertility. 2) Cows BCS 2 or less at calving less likely to conceive during a restricted mating period as may be anoestrus during much of breeding period. 3) Aim for target condition scores at key times of year (different for spring vs autumn). 4) Separate off thin cows and feed extra or wean early. 5) Ensure adequate trace element/vitamin/mineral supplementation. Copper and Selenium may often require supplementation. 6) Avoid sudden changes in level of feeding until 6w post mating period. 7) Minimize periparturient problems-e.g. dystocia. Overconditioned cows are at more risk of periparturient problems. 8) Have control measures to avoid introduction of infectious dz's that may affect fertility, e.g. venereal Campylobacter, Leptospirosis, BVD, IBR. 9) PD cows 6-8w after end of breeding period and plan culling policy. |
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What type of replacements pose the lowest biosecurity risk? |
Homebred replacements *2nd best is to buy yearling/bulling heifers from a source with known dz status. |
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When is the aim for heifers to calve down? |
2-2.5 years old to easy calving bull in good BCS (3) 2-3w ahead of main herd calving period. |
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What steps can be taken to maximize replacement heifer breeding management? (9) |
1) Isolate from main herd for 3-4w and screen purchased replacements for BVD status, vax for Leptospirosis, BVD, and IBR depending on herd health status. 2) Check for freemartins/non breeders and misalliance pregnancies. 3) Ensure adequate nutrition prior to and during mating period. Feed for maintenance and growth (0.7 kg/day). 4) Aim for critical minimum mating weight at first service of around 65% of mature cow weight. 5) Ensure no trace element deficiencies or parasite problems prior to mating. 6) Mate with easy calving bull for 6-7w only. 7) PD and remove non-pregnant heifers for sale. 8) Feed during pregnancy for CS3 at calving, too fat-dystocia, too thin-extended post-partum anoestrus. 9) If possible run first calvers as a separate group until pregnant again. |
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What are the advantages of AI? (5) |
1) Allows use of best bulls with known EBV's for various traits. 2) Reduces costs of keeping stock bulls? 3) Removes risk of venereally transmitted dz's. 4) May tighten calving period as all cows receive first service on day 1 of breeding period. 5) No need for oestrus detection if fixed time AI is used. |
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What are the disadvantages of AI? (3) |
1) Heat detection may be a problem if not using fixed time AI. 2) More labour intensive (handling for AI, etc). 3) Cost. |
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What are the 2 methods for oestrus synchronization for fixed time AI? Describe each. |
1) Progesterone releasing intravaginal devices (PRID or CIDR) *Device inserted for 8-10d with prostaglanding (luteolytic) injection given 1-2d before device removed. AI at 48h and 72h after device removed or once at 56h. 2) Double prostaglandin injection *Cows/heifers injected twice with PG, 11d apart and fixed time AI 72h and 96h following second injection. Best restricted to maiden heifers as results may be poor in cows due to anoestrus at the time of synchrony. |
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Which method of oestrus synchronization for fixed time AI is superior in beef cows? Why? |
Progesterone based synchrony. Induces oestrus and ovulation in cows that may be anoestrus. |
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What steps can be taken to maximize pregnancy with fixed time AI? (5) |
1) Ensure cows/heifers on a good steady plane of nutrition and cyclical before synchrony, and for 6w following AI. 2) Ensure no trace element deficiencies/parasite problems and that infectious dz's controlled. 3) Have good handling system for AI, etc. Minimize stress. 4) Will get higher pregnancy rates if use double AI. 5) Realistic pregnancy rates achieved to synchronized AI: cows 55-65% and heifers 65-75%. |
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What can be done by the farmer to investigate beef herd fertility analysis and benchmarking? |
Keep good records. |
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What is the expected pregnancy rate per service of bulls? |
60%. All cows cycling at start of breeding season can expect 84% in calf in 6w breeding period or 94% in 9w. |
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What 2 components comprise a histogram for beef herd fertility analysis and benchmarking? |
1) From dates bull run with cows work out theoretical date of start of calving period (date bull enters herd + 285d). 2) Use this date as day zero on x-axis. Work out number of cows that calf in each 3w period from day 0 and create histogram (cows calving early are included in 1st 3w period). |
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What are the targets for: 1) Barren cow rate 2) Cows calved in 1st 3w of calving period 3) Calf crop % 4) Pregnancy rate % |
1) less than or equal to 5% 2) less than or equal to 65% 3) less than or equal to 94% 4) less than or equal to 95% |
