Term
When is adequate nutrition needed in ewes? |
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Definition
during the last six weeks of pregnancy when 75% of foetal growth occurs, to ensure appropriate lamb birth weight
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Term
| foetal development during pregnancy in relation to dietary energy supply. |
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Definition
First trimester – implantation
Second trimester- placental development
Third trimester- foetal growth and development
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Term
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Definition
- has not improved over the past 40 years
factors include: including farm management, level of flock supervision and infectious diseases contribute to such losses, lamb birthweight together with ewe body condition score and colostrum accumulation at lambing remain fundamental to ensuring a good start for the lamb during the critical first 36 hours of life.
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Term
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Definition
Dietary energy supply around the time of implantation is likely to be adequate because autumn grass is still available after flushing ewes.
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Term
| Second trimester: placental development |
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Definition
Furthermore, weather and/or grazing conditions need to be severe for 10 to 14 days to seriously impair placental development. However, reduced lamb birthweight can occur when placental development has been limited by competition in the uterus for caruncles resulting in a reduced number of placentomes per foetus. This situation is not uncommonly encountered in multiple litters where the birth of twins with disproportionate weights e.g. 5.5 kg versus 3.5 kg probably indicates that three embryos implanted and underwent early foetal development but one foetus failed to develop further and was resorbed. The limited number of caruncles available to the remaining foetus in the ipsilateral horn resulted in poor growth and much reduced birthweight compared to the co-twin which developed without competition in the contralateral horn.
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Term
| Third trimester: foetal growth and development |
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Definition
- the direct influence of dam energy under nutrition during late gestation on reduced lamb birthweight and inadequate accumulation of colostrum in the udder.
- found significant higher lamb perinatal mortality in the progeny of underfed ewes with the effects greater in triplet than twin lambs, singletons were largely unaffected by dam nutritional status.
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Term
| how can you determine dietary energy supply relative to metabolic demands |
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Definition
during late gestation
- measuring ewes serum 3-OH butyrate concentration
- increased 3-OH butyrate values reflect inefficient fatty acid utilisation caused by high glucose demand from developing foetuses which are not matched by glucogenic amino acid supply.
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Term
| Farm visit as part of veterinary flock health plan |
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Definition
- ewes due to lamb should be body conditioned scored and blood sampled four to five weeks before the start of lambing time thereby allowing to implement dietary changes.
- random sample of 15-20 should be sample
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Term
| Farm visit as part of veterinary flock health plan |
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Definition
- ewes due to lamb should be body conditioned scored and blood sampled four to five weeks before the start of lambing time thereby allowing to implement dietary changes.
- random sample of 15-20 should be sample
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Term
| Results and interpretation of blood samples |
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Definition
3-OH butyrate- in relation to foetal numbers
- once the mean 3-OH butyrate concentration has been determined, flock should then be re-visited and blood samples collected two weeks later to check on progress and further monitor any changes in ewe body condition scores
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Term
| evaluation of protein status |
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Definition
blood samples: blood urea nitrogen- indicates short term protein intake, and albumin which reflects longer term protein status.
- recent feeding can increase BUN concentration. and blood samples should be collected either before concentrate feeding or at least four hours later to avoid post-prandial increases
- Low BUN concentrations usually indicate a shortage of rumen degradable protein. Serum albumin concentrations fall during the last month of gestation as immunoglobulins are manufactured and accumulate in the udder thus serum albumin concentrations in the region of 26 to 30 g/l are ‘normal’ during the last month of gestation. Low serum albumin concentrations in a high percentage of ewes may also indicate chronic fasciolosis.
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Term
| follow up visit during lambing time |
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Definition
- measurement and recording of lamb birthweight and ewe condition scores is essential to determine how succesful the flock nutrition has been during late gestation.
PM of dead lambs
- pay attention to triplets
- provide written notes and records |
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Term
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Definition
- ewes vaccinated against clostridial diseases four weeks before lambing
- vaccinate flock as two separate groups with the later lambing ewes vaccinated one week to 10 days later than those ewes lambing during the first week.
- make sure fleece is dry during subcutaneous injection cause can lead to absccess formation.
- By ensuring ewes are in good condition at vaccination time, and receiving an appropriate level of supplementation as determined by the blood samples collected, you will guarantee plentiful accumulation of protective antibodies in the colostrum at lambing time.
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