Inflammatory status in Holstein and Montbéliarde cows during the periparturient period and sequential feed restriction challenges.

In dairy cows, the period immediately preceding calving is responsible for shifts in hormonal and nutritional status characterised by mobilization of body fat, proteins, and bone minerals to support the onset of lactation. After calf birth, the dairy cow often experiences negative energy balance despite a gradual increase in dry matter intake (DMI). Calving itself can alter the innate immune system, and early lactation cows must balance the nutrient use between metabolic and inflammatory responses to sustain milk production. It remains unclear whether systemic inflammation contributes to or results from reduced feed intake, negative energy balance and fat mobilization during this period. Therefore, to enable improved understanding, the objectives of the study were to investigate the effects of feed efficiency in two breeds on the inflammatory status during the pre-calving period, during mid-lactation, and by introducing a sequential nutritional challenge of four successive four-day feed restriction (FR) periods.

Fourteen Holstein and 14 Montbéliarde multi-lactation cows were selected from 40 animals based on extreme residual feed intake (RFI) during the first 10 weeks of lactation and classified as RFI+ (0.42 to 2.34 kg DMI/day) [less efficient] or RFI− (−2.38 to −0.44 kg DMI/day) [more efficient]. The cows were studied from week −3 to +22 of lactation. Starting at 86 ± 9 days in milk, the cows underwent four periods of 4-day FR to meet 50% of individual net energy requirements (FR1, FR2, FR3, FR4) followed by a 10, 3, 3, and a 10-day recovery periods of ad libitum intake, respectively. Blood samples were collected from the coccygeal vessels before the morning feeding on week −3, +2, +12, and +22 of lactation and on day 0 and 4 of each FR. Plasma was analyzed using the Milliplex Bovine Cytokine/Chemokine Panel method.

For both breeds, tumour necrosis factor α (TNFα), IL-1α, IL-10, monocyte chemo-attractant protein-1 (MCP-1) and IL-6 were significantly lower on week +2 than week −3 and remained steady through lactation, but IL-8 increased at week +2 compared with week −3. Concentrations of TNFα, IL-10, MCP-1 and IL-8 were higher in Holsteins than in Montbéliardes. The concentration in macrophage inflammatory protein −1β (MIP-1β) was higher in RFI+ than in RFI−. The significant feed restriction effects on the innate immune system were small and not systematic across FR1 to FR4. The sequential nutritional challenge induced relatively small changes in cytokine and chemokine concentrations, indicating that the negative energy balance did not affect the immune system, despite consistent metabolic responses. Breed, feed efficiency and repeated feed restrictions had also limited effects on the system.

Conclusions: The results did not support the underlying hypotheses of the objectives as most indicative measurements apparently did not have an appreciable effect on the immune system.