Energy requirements and energy supply of dairy cows during early lactation in pasture-based systems
2024
Walsh, S. | Delaby, Luc | Mckay, Z.C. | Egan, M. | Teagasc - The Agriculture and Food Development Authority (Teagasc) | University College Dublin [Dublin] (UCD) | Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage [Rennes] (PEGASE) ; Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Rennes Angers ; Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
International audience
显示更多 [+] 显示较少 [-]英语. The objective of the current study was to measure energy requirements and intake profiles for grazing dairy cows in early lactation. Cows were offered a daily herbage allowance to achieve a post-grazing sward height of 4 cm with 3 kg concentrate/cow/day. They were offered silage supplementation when necessary during periods of high rainfall which reduced intake due to difficult grazing conditions. Individual energy (UFL; unité fourragère lait) requirements were calculated based on energy required for milk production, maintenance and growth (< 40 months); UFL supply was calculated based on measured dry matter intake and the UFL content of the feeds. Week of lactation and parity had a significant effect on UFL requirement, primiparous (parity 1) animals had the lowest UFL requirement (15.9 UFL cow–1 day–1), followed by second (parity 2) and third parity (parity 3) animals (17.8 and 19.0 UFL cow–1 day–1, respectively). The UFL supply followed the same trend with parity 1, 2 and 3 animals consuming 12.0, 15.4 and 16.4 UFL cow–1 day–1, respectively. This difference in energy intake and demand resulted in cows being in a state of negative energy balance and led to bodyweight loss of 1.05 kg/cow/day over the first 12 weeks of lactation.
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