Dairy heifers intake capacity: are estimated values still correct? - AgroParisTech Accéder directement au contenu
Communication Dans Un Congrès Année : 2023

Dairy heifers intake capacity: are estimated values still correct?

Résumé

On-farm heifers feeding practices often challenge on-going recommendations, some advisors hypothesizing that equations developed in early 80’s to predict heifers intake capacity (IC) are no longer suitable for current animals. Three complementary approaches were performed to test this hypothesis. First, a survey on 21 advisors in 2020 indicated that 16 of them considered that algorithms they were using adequately predicted heifers IC. These algorithms were based on information regarding body weight and ration composition, but advisors indicated that most farmers do not weigh heifers or analyse feed. In a second approach, feed intake from 58 groups of heifers, from 4 experimental farms, was analysed. The groups size averaged 15 heifers (±7), weighing 400 (±84) kg and aging 15 (±3.5) months. The main forages used were corn silage, hay and wrapped haylage. Differences between predicted dry matter intake (DMI) and measured DMI was in average -0.3 kg, difference being less than 1 kg DMI/day in 2/3 of the cases. Finally, in a third trial, individual DMI were measured during autumns 2019 and 2020, on respectively 47 and 42 heifers of Holstein (n=54) and Normande (n=35) breeds, aged 17 months on average. They were fed ad libitum with grass silage in 2019 and hay in 2020. IC was evaluated thanks to the determination of fill value of forage, through the DMI of the heifers or from an alternative method using DMI measured on adult sheep fed ad libitum. IC was also determined thanks to the equation IC= aBWb. The ‘a’ coefficient was adjusted in both approaches by setting the coefficient ‘b’ to 0.9, as previously recommended. In the first approach (heifers intake), ‘a’ value was similar to previous published results (0.03915, vs 0.03729 and 0.03749 for silage and hay, respectively). Similar results were observed in the second approach with the sheep intake and the forages fill value estimations. It was concluded that the intake prediction equation used since the 80’s remains valid. The lack of heifers weighing and/or of knowledge of forages values probably resulted in wrong initial hypothesis.
Fichier non déposé

Dates et versions

hal-04284274 , version 1 (14-11-2023)

Identifiants

  • HAL Id : hal-04284274 , version 1

Citer

J. Jurquet, Yannick Le Cozler, D. Tremblais, Frédéric Launay, Luc Delaby. Dairy heifers intake capacity: are estimated values still correct?. 74. Annual meeting of the european federation of animal science (EAAP), EAAP, Aug 2023, Lyon, France. pp.637. ⟨hal-04284274⟩
31 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More