Effect of backfat thickness and oestradiol benzoate on reproductive performance of dorper ewes
Application of oestrus synchronisation had been implemented widely in order to improve farm husbandry. However, information regarding application of intravaginal pessary FGA in sheep especially for Dorper breed reared in Malaysia is lacking. In addition, backfat thickness will be examined to have...
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| 格式: | Thesis |
| 语言: | English |
| 出版: |
2017
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| 主题: | |
| 在线阅读: | http://psasir.upm.edu.my/id/eprint/104543/1/HAZLINDA%20BINTI%20HASIM%20-%20IR.pdf |
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| 总结: | Application of oestrus synchronisation had been implemented widely in order to
improve farm husbandry. However, information regarding application of
intravaginal pessary FGA in sheep especially for Dorper breed reared in
Malaysia is lacking. In addition, backfat thickness will be examined to have a
better picture on the oestrus synchronisation of sheep production. Two
experiments were carried out in this study, the first experiment consisted of 34
Dorper crosses ewes, randomly allocated into three groups where all ewes
received intravaginal pessary FGA with Corn oil (CO; n=11), low doses OB
(LOB; n=11) and high doses OB (HOB; n=12). A day before pessary removal, 1
ml of PG was injected all ewes regardless of their treatment. Natural mating
and oestrus signs observation was conducted using four rams (alternate) after
24 h post pessary removal and OB injection. Results showed 100% of ewes in
LOB and HOB groups had oestrus within 60h observation while only 36.36% of
ewes in CO group. Meanwhile, standing of oestrus in both LOB and HOB
groups shown shorter interval compared to CO group. In second experiment,
two factors that are backfat thickness (BFT) and OB doses was analysed with
factorial design. This experiment consisted of 71 ewes allocated to two BFT
(Thin: Tn=37; Thick: Tk=34) and three doses of OB (Corn oil: CO=25; Low
dose of OB: LOB=24 and High dose of OB: HOB=22). Synchronisation
protocols were same as previous experiment. Results of oestrus observation
showed that there is no interaction between BFT and OB doses, thus main
factors was analysed separately. Group that received LOB and HOB had
earlier onset of oestrus (LOB=24.5±0.2 h; HOB=26.1±2.1 h) and standing of
oestrus (LOB=26.8±1.2; HOB=31.2±2.6 h) compared to CO group (onset of
oestrus=39.4±2.6 h; standing of oestrus=44.6±2.3 h). The mean concentration
of P4 after 24 h of post pessary removal in all groups showed no significant
difference (p>0.05). There was no significantly different (p>0.05) on the
pregnancy rate among the groups. There was an interaction between BFT and
OB doses for the lambing rate. Ewes that received CO and Tk had the highest
(50%) lambing rate compare to other groups. The concentration of leptin
between Tn and Tk showed no significant different (p>0.05) during oestrus
synchronisation. As conclusion, regardless of OB doses able to synchronised
ewes. Further research on BFT is needed to determine best parameter during
oestrus synchronisation. |
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