Diversity of dairy goat lactation curves in France

Abstract

A high level of production at the peak of lactation may be associated with animal health disorders, high feeding costs, and reduced milk supply throughout the year. The objective of this study was to typologize the lactation curves in French dairy goats and analyze the influence of environmental and genetic factors on these curves. The data set consisted of 2,231,720 monthly test-day records of 213,534 French Saanen and Alpine goats recorded between September 2008 and June 2012. First, principal component analysis classified the shape of the lactation curves into 3 principal components: the first component accounted for milk yield level throughout lactation, the second component accounted for lactation persistency, and the third component accounted for milk yield in mid-lactation. Then, from the principal component scores, the lactations were clustered into 5 different groups. Most lactations had a similar shape to the mean curve, except 30% of the lactations that fell into 3 clusters that had a high production level at the peak and then a different persistency according to cluster. Estimated breeding value for milk yield and home region of breeding were the factors most related to lactation production level. Month of kidding, breed, and gestation stage had the biggest effect on persistency. Month of kidding was the factor most strongly linked to mid-lactation production. A herd effect was observed on all 3 principal components.

Effects of month of kidding, parity number, and litter size on milk yield of commercial dairy goats in Australia

“…First-parity goats had the lowest milk yields and third-parity goats had the greatest milk yields (431 vs. 587 L, respectively; P < 0.001), with goats in fourth or greater parity performing intermediately (Table 3). This increase and decrease according to parity number agrees with several published studies in dairy goats (Gipson and Grossman, 1990;Goetsch et al, 2011;Arnal et al, 2018). According to Lérias et al (2014), the greater milk production in multiparous goats can be explained by older goats tending to have a higher proportion of alveoli developed in the previous lactation added to those developed in subsequent lactations, increasing secretory parenchyma and udder volume compared with primiparous goats.…”

“…In the present study, differences in productivity varied as goats advanced into lactation, gradually decreasing between goats in first and third parity and increasing between goats in third and fourth or greater parity. Our results are supported by others who reported increased initial and peak milk yields with increasing parity (until about third or fourth parity), later peak with greater persistence in first-parity goats, and decreased persistence with increasing parity (Gipson and Grossman, 1990;León et al, 2012;Arnal et al, 2018). Figure 2 shows the proportion of goats being removed from the milking herd (dried off or culled) as lactation progresses.…”

“…Furthermore, the herd's average milk yield peaked in February 2017 (summer) and was lowest in June 2016 Figure 1c), a clear indication of substantial effects of photoperiod on goat productivity. Arnal et al (2018) demonstrated that the shape of the goat lactation curve is tied to the duration of the photoperiod and that month of kidding is strongly linked to mid-lactation production. Moreover, multiple studies have reported the influence of month of kidding (season of the year, more specifically) on peak yield, lactation persistence (ability to maintain production at a higher level after peak yield), and CMY of dairy goats (Montaldo et al, 1997;León et al, 2012).…”

Lactation curve model with explicit representation of perturbations as a phenotyping tool for dairy livestock precision farming

“…Several factors (e.g., breed, parity, 406 seasonality and season of kidding) can affect characteristics of the lactation curve. The 407 differences found in this study between primiparous and multiparous goats are consistent with previous studies [23,24] with primiparous goats being less productive, with a lower peak yield 409 and a greater persistency. Despite the lack of a significant effect of parity, our results are 410 consistent with previous studies [24] where primiparous goats had a peak later than 411 multiparous (see Table 1).…”

“…The total milk production for the unperturbed curve was 361 increased by 32.55 % between the first parity and the second parity, 5.20 % between the 362 second parity and the third parity and by 1.01 % between the third parity and the fourth parity. 363These results are consistent with Arnal et al[23]. 364 365 Individual unperturbed PLM-based lactation curves for increasing parity number (fit 366 on 319 lactation data; atypical curves correspond to outlying estimates of the parameter c 367 governing milk persistency).…”