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farm reproduction
Term | Definition |
---|---|
gestation length for cow | 283 days |
gestation length for sheep | 149 days |
gestation length for pig | 115 days (3 months, 3 weeks, 3 days) |
oestrous cycle for cow | 21 days |
oestrous cycle for sheep | 17 days |
oestrous cycle for pig | 21 days |
oestrous / heat for cow | 18-24 hours |
oestrous / heat for sheep | 36 hours |
oestrous / heat for pig | 2-3 days |
give 2 advantages of A.I | - can select the correct bull for each female - can improve the genetics of the herd - reduces spread of disease -bull can be dangerous |
give 2 advantages of a stock bull | - can detect heat - less labour intensive |
give 2 disadvantages of A.I | - labour intensive (getting animals in etc) -easy to miss a heat if not using heat detection aids -can be expensive - technician call out |
give 2 disadvantages of stock bull | - dangerous -expensive to keep -replace every two years to prevent inbreeding |
explain the AM / PM rule | if heat is observed in the morning serve in the evening and vice versa |
name one heat detection aid and explain how it works | tail paint / pressure pad / pedometer/ raddle harness |
explain the term polyoestrus | animals that have oestrous cycles throughout the year |
seasonally polyoestrous | animals that have a number of oestrous cycles but only at certain times of the year |
give an examples of an animal we have studied that is seasonally polyoestrous | sheep |
what triggers sheep to come into oestrous? | low levels of day light --> increase levels of melatonin --> triggers hypothalamus to release FSH |
in terms of sheep explain the term flushing | post weaning ewes are put on a low plane of nutrition (high stocking density) 3-4 weeks before ram is introduced put on high plane of nutrition (low stocking density) |
what are the advantages of flushing | - more eggs released - higher conception rates - better implantation - more regular oestrous |
name 2 ways to synchronise breeding of ewes | ram effect / sponging / breeding out of season |
list the steps involved in breeding out of seasons | 1. insert progesterone sponges 2. after 12-14 days remove sponges 3. 12-36 hours later all come into heat |
what is the difference between sponging and breeding out of season? | with breeding out of season have to inject with PMSG |
What is steaming up? | in final 6-8 weeks of pregnancy of ewe gradually increasde concentrates to 500g for singles and 700g for doubles and triples / day = prevent twin lamb disease. |
name the first milk produced by a cow/ewe/sow | colostrum |
what are the 3 positive effects of colostrun | warming effect / laxative effect / immunity & antibodies |
how can we prevent mortality at calving / lambing time | 1. observe 2 isolate 3 assist if in difficulty (have equipment ready) 4 call vet if necessary |
name three things a farmer should do / check after the birth of young | check airways / remove mucous ensure mother licks ensure offspring suckles dip navel with iodine |