Agriculture Reference
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tissue mass (on day 35) was unaltered (Athorn
et al.
, 2012a). No difference in IGF-1
concentrations were reported between these diets. Evidently, more work is required with
models that manipulate insulin, IGF-1, fats in the diet, and other potential modulators
of luteal function such as PGE2 (Figure 2.2).
2.4.5
Role of nutrition in risk management during early gestation
The effects discussed above of low feed levels during established luteal function on embryo
survival and maintenance of pregnancy have implications for situations where there is an
increased risk of pregnancy failure, such as in group-housing with competition for feed or
Days from mating
0
5
10
15
20
25
30
35
LH independent
LH dependent
Luteal capacity
developing
Uterine P4 supply
mainly systemic
Luteal capacity established
Uterine P4 supplied from both systemic and local transfer
High feed level increases luteal output through insulin,
IGF and from about day 12, also by LH
High feed level
reduces systemic
P4 and P4 supply
to uterus until
day 5-7
Ovarian-uterine transfer of P4 probably overcomes
systemic reduction in P4
Speci
c nutrients may promote blastocyst development?
E.g. leucine, glutamine
Implantation and vascularisation supported by speci
c
nutrients, e.g. arginine
Figure 2.2. Conceptual diagram illustrating the dynamics in luteal mass (cross sectional area of corpora lutea,
closed symbols) and systemic progesterone (open symbols) in the embryonic stage of pregnancy, explaining
how different aspects of nutrition (feed level and specific nutrients) can impact differently at different stages
of the embryonic period.
