Factors affecting the response of pregnant and lactating ewes to vitamin E supplementation
Abbi, A. (2020) Factors affecting the response of pregnant and lactating ewes to vitamin E supplementation. Doctoral thesis, Harper Adams University.
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Abstract
A series of experiments were carried out to investigate the effect of body tissue reserves and source of vitamin E on the response of pregnant and lactating ewes to supra-nutritional levels of vitamin E. In experiment one, at day 77 of pregnancy 48 twin-pregnant ewes (Suffolk x Mule) with a live weight (LW, 82.89 kg) and condition score (C, 3.32) were allocated to one of two groups, and fed to achieve a mean C of either < 2.5 (LC) or > 3.0 (HC) prior to housing. At day 103 (week -6) ewes were individually allocated to one of two concentrates containing either a low vitamin E (LV) (74 mg/day) or high vitamin E (HV) (513 mg/day) level and offered straw ad-libitum. The results indicated that there was no significant interaction between nutritional restriction and vitamin E supplementation. High condition score ewe had a higher C at week -6 and lost more C pre-partum. Ewe C had no effect onpost-partumC loss, but LC ewe had a higher LW loss. They also had a higher litter weight. Level of vitamin E had no impact on ewe or lamb performance, but ewes fed HV had higher plasma and colostrum α-tocopherol concentration. In experiment two, at day 103 of pregnancy (week -6), 44 twin bearing Suffolk x Mule ewes with a mean live weight (LW) of 77 kg and body condition score(C) of 2.9 were allocated by parity, LW and C to either a grass silage (GS) or straw (S) based diet supplemented with either a low (L, 240 mg/day) or high (H, 750 mg/day) vitamin E concentrate to provide 4 treatments; GSLV, GSHV, SLV and SHV. Forages were offered ad-libitum. The results show that pre-partum, ewes offered GS had a higher LW gain and tended to have a lower C loss than those offered S. In addition, they had a higher placental weight. However, the forage source had no effect on litter weight. Post-partum, lambs from ewes offered S were heavier at week +8. Ewes offered high vitamin E (HV) had a higher placental weight, cotyledon weight, litter weight and were heavier at week +8 than those offered low vitamin E (LV).In experiment three, 12 castrate lambs (LW, 25 kg) were housed in raised floor pens (1.5 x 2.0 m) in a sheep metabolism room and allocated to either a grass silage (GS) or straw (S) based diet supplemented with either a low (LV, 5.3 mg/kg LW) or high (HV, 10.0 mg/kg LW) vitamin E concentrate to provide 4 treatments; GSL, GSH, SL and SH. The experiment was run over two periods with three lambs being allocated to each treatment in each period, giving six replicates per treatment. The results showed that lambs' offered grass silage as a natural source of vitamin E had higher blood plasma α-tocopherol concentration than those offered α-tocopherol acetate from concentrates. In addition, high vitamin E supplementation reduced diet DM and fibre digestibility resulting in a reduction in the digestible energy (DE) and metabolisable energy ME content of the diet.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Divisions: | Animal Production, Welfare and Veterinary Sciences (to 31.07.20) |
| Depositing User: | Ms Kath Osborn |
| Date Deposited: | 05 Mar 2021 10:23 |
| Last Modified: | 05 Mar 2021 10:23 |
| URI: | https://hau.repository.guildhe.ac.uk/id/eprint/17654 |
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