Repeatability of traits for characterizing feed intake patterns in dairy goats: a basis for phenotyping in the precision farming context

Abstract

In ruminants, feeding behaviour variables are parameters involved in feed efficiency that show variation among individuals. This study aimed to evaluate during the first two production cycles in ruminants the repeatability of feed intake pattern, which is an important aspect of feeding behaviour. Thirty-five dairy goats from Alpine or Saanen breeds were housed in individual pens at four periods (end of first gestation, middle of first and second lactations and middle of second gestation which is also the end of first lactation) and fed a total mixed ration (TMR) ad libitum. Individual cumulative dry matter intake (DMI) was automatically measured every 2 min during the last 4 days of each period. Feed intake pattern was characterized by several measures related to the quantity of feed eaten or to the rate of intake during the 15 h following the afternoon feed delivery. Two main methods were used: modelling cumulative DMI evolution by an exponential model or by a segmentation-clustering method. The goat ability to sort against dietary fibre was also evaluated. There was a very good repeatability of the aggregate measures between days within a period for a given goat estimated by the day effect within breed and goat, tested on the residual variance (P > 0.95). The correlations between periods were the highest between the second and either the third or fourth periods. With increasing age, goats sorted more against the fibrous part of the TMR and increased their initial rate of intake. Alpine goats ate more slowly than Saanen goats but ate during a longer duration. Principal component analysis (PCA) was performed on all the aggregate measures of feed intake patterns. The factor score plots generated by the PCA highlighted the opposition between the different measures of feed intake patterns and the sorting behaviour. The projection of the animals on the scoring plots showed a breed effect and that there was a continuum for the feed intake pattern of goats. In conclusion, this study showed that the feed intake pattern was highly repeatable for an animal in a given period and between periods. This means that phenotyping goats in a younger age might be of interest, either to select them on feeding behaviour and choose preferentially the slow eaters or to adapt the quantity offered and restrict feed delivery to the fast eaters in order to increase feed efficiency and welfare by limiting the occurrence of acidosis, for example.

Inter- and intra-individual variability of feeding behaviour in group housed dairy goats

“…A previous study in individually housed goats (Giger-Reverdin et al, 2019) has shown a good repeatability of individual feeding behaviour between the end of their first gestation and the middle of their second gestation. Our study also showed a good repeatability between goats tested in mid-and late lactation.…”

“…Using this method, we were able to determine six variables of feeding behaviour (Table 1). In accordance with previous work (Giger-Reverdin et al, 2019), special emphasis was given to the first meal after feed delivery.…”

“…This peak activity can influence differently individual animal behaviour (Grant and Albright, 2001;DeVries et al, 2003a), and the addition of fresh feed stimulates feeding behaviour, which may make the first meal more suitable for detecting individual differences. Giger-Reverdin et al (2019) found that the proportion of feed consumed during the 90 or 180 min following feed distribution was the most relevant criteria for characterizing feeding behaviour. In our study, the size of the first meal reflected the daily feed intake of the individual goats.…”

“…As Saanen goats were heavier than Alpine goats, we expected a difference in daily feed intake between the breeds, whichall other things being equalwould have led to changes in the meal pattern. Indeed, Giger-Reverdin et al (2019) reported that Saanen goats ate faster, for less time and with fewer feeding periods than Alpine goats. However, they also found that Saanen goats ate less dry matter daily than Alpine goats, although Saanen goats are heavier, and hypothesized that Saanen have less stable rumen conditions and poorer digestion than Alpine animals.…”

A novel modelling approach to quantify the response of dairy goats to a high-concentrate diet

“…The index described here allows ranking of ruminants for their capacity to buffer the effect of a highly fermentable diet, and subsequently refining strategies to select for animals more resistant to SARA. Finally, in livestock precision farming, this index helps to adapt feed composition to an animal’s rumen capacity and thereby efficiently valorise food composition 12 .…”