Short-term adaptive capacity of dairy goats to a two-days nutritional challenge

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Gindri, Marcelo | Friggens, Nicolas, N.C. | Puillet, Laurence

Edité par CCSD -

International audience. Adaptive capacity, in the short or long term, in dairy goats, is an important trait for sustainable livestock production, given the increasingly variable environments due to climate change. Good adaptive capacity should favour productive lifespan and in turn long-term efficiency. The objective of this study was to evaluate milk yield (MY) and plasma glucose responses of first lactation goats to a two-day nutritional challenge. The goats were daughters of Alpine bucks divergently selected for longevity (LGV+ and LGV-; 190 days in lifespan difference). They were fed with one of two rearing diets (RD), differing in energy density, from weaning to mid-gestation. The experimental challenge started at 29±2.5 days in milk (DIM). At 33±2.5 DIM, all goats switched from a normal lactation diet into a straw-only diet for two days. Individual MY (kg/d) and plasma glucose (g/l) were recorded daily for 17 days (5 days before challenge, 2 days of challenge, and 10 days after the challenge). The time-series data was split into four-time variables representing the phases pre-challenge, rate of response to challenge, and linear and quadratic rates of recovery from challenge and used in a mixed model considering LGV and RD and the 4 time-variables as fixed effects. Animal was included as a random effect on all 4 of the time-variables. LGV affected only MY rate of recovery from challenge (P≤0.046) while RD did not affect any trait (P≥0.17). LGV- goats presented quicker and sharper recovery from challenge than goats from the longer longevity line. However, this LGV effect on MY linear rate of recovery from challenge was no longer significant when plasma glucose was used as a covariate (P=0.096). These results suggest goats from the LGV- line drive glucose metabolism towards quick MY recovery after a two-day nutritional challenge in early lactation while LGV+ goats drive glucose metabolism towards other functions rather than quick MY recovery. Diet during early life seemed not to affect the goat’s capacity of rebounding MY after short-term nutritional challenge in the following early lactation

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