Sheep & Goats

Extended lactations in Alpine goats farmed in Lombardy: production patterns and modelling.

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Abstract

Extended lactation (EL) is increasingly considered a strategy to improve the sustainability of dairy goat production by reducing reproductive frequency, limiting surplus non-replacement offspring, and extending animals' productive lifespan. However, the EL implementation and its performance under commercial conditions remain poorly documented. This study aimed to characterize variability in lactation length and milk production performance in Camosciata delle Alpi (CAM) and Saanen (SAA) goats reared in Lombardy (Italy), using field data from the CapraGEN project, and to evaluate whether mid-lactation performance is associated with the decision to prolong lactations. A total of 36,167 official milk test-day records from 2,157 goats in eight commercial herds monitored between 2013 and 2025 were analyzed. No pedigree information was available. Lactations were classified according to total days in milk (DIM) as short (200-250 DIM), normal (251-400 DIM), prolonged (401-485 DIM), and extended (≥486 DIM). Only lactations with at least six test-day records and starting after DIM 5 were retained. Daily milk yield was modeled using a Wood function for each goat × parity level, thereby summarizing multiple test-day records into a single production trajectory per lactation. Model outputs were used to estimate cumulative milk yield up to 210 DIM, corresponding to the onset of the reproductive season, which was adopted as an indicator of mid-lactation performance independent of final lactation length. Average daily milk yield ranged approximately from 2.0 to 4.0 kg/day, with substantial variability among herds and breeds, reflecting heterogeneous management and production conditions. In all herds, correlations between cumulative milk yield at 210 DIM and total DIM were positive and significant (r = 0.22-0.51; P < 0.05), indicating that goats with higher mid-lactation performance were more likely to undergo prolonged or extended lactations, although the strength of the correlations varied markedly among herds. Mean cumulative milk yield at 210 DIM was 896 kg and 850 kg for EL, compared with 684 kg and 785 kg for short lactations, respectively, in CAM and SAA goats, reflecting the increasing magnitude of production associated with longer lactations. At the upper end of the observed variability, maximum lactation length reached 2,565 DIM in CAM and 1,049 DIM in SAA goats. These results highlight the wide range of lactation durations achievable under commercial conditions and represent a valuable phenotypic resource for genomic analyses of lactation persistency. The availability of SNP-chip genotypes generated using the Neogen GGP Goat 70K array will allow the estimation of heritability and the implementation of genomic prediction once data collection is completed in the involved herds. Moreover, they provide a field-based overview of ELs and support the use of mid-lactation cumulative yield as a potential phenotype for genetic selection and as an indicator for EL management strategies.

Keywords: 2026

How to Cite:

Bagnato, A., Bernini, F., Ferrari, C. & Strillacci, M., (2026) “Extended lactations in Alpine goats farmed in Lombardy: production patterns and modelling.”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285613. doi: https://doi.org/10.31274/wcgalp.23754

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