Talukder, Saranika, Cheng, Long, Eckard, Richard, Munidasa, Sineka, Barnes, Lachlan, Morton, John, and Cullen, Brendan R. (2025) Exploring the impact of replacement rates on carbon footprint in south-east Australian dairy herds. Animal Production Science, 65. AN24247.

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Abstract

Context: Greater replacement rates in dairy herds lead to increased costs for rearing and/or purchasing replacement heifers and greater herd greenhouse gas (GHG) emissions.

Aims: This study aimed to estimate current GHG emissions and potential improvements in net farm emissions (NFE) and emission intensity (EI) by reducing replacement rates (percentage of calvings in the herd in the year that were by first calving heifers) using a series of eight case study farms.

Methods: The research was conducted by modelling eight Australian case study farms (five from northern Victoria/southern New South Wales and three from the Gippsland region) using farm-specific data. Data included herd structure, milk production, feed quality and quantity, and energy, fuel, and fertiliser usage. GHG emissions were estimated using the Dairy GHG Accounting Framework tool (ver. 14.5), calculating NFE and EI in megagram of carbon dioxide equivalents (Mg CO2e) and kilograms of carbon dioxide equivalent per kilogram of milk solids (kg CO2e/kg MS). The study modelled reducing the replacement rate by 5, 10, and 15 percentage points.

Key results: The average (±s.d.) EI per kilogram of MS for the eight case study farms was 15.8 ± 3.5 kg CO2e/kg MS. A 15-percentage point reduction in replacement rate was estimated as leading to reductions in EI per kilogram of MS ranging from 0.9 to 1.7 kg CO2e/kg MS across the case-study farms. However, NFEs were estimated as increasing with reductions in replacement rate for five of the eight case study farms.

Conclusions: Reducing the replacement rate can reduce EI (measured in kg CO2e/kg MS) but increase NFEs.

Implications: The findings underscore the importance of considering both environmental factors, such as GHG emissions, and economic aspects, such as net farm income, when evaluating and implementing strategies for sustainable dairy farming.

Item ID:	86194
Item Type:	Article (Research - C1)
ISSN:	1836-5787
Copyright Information:	© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)
Date Deposited:	22 Jul 2025 03:41
FoR Codes:	30 AGRICULTURAL, VETERINARY AND FOOD SCIENCES > 3003 Animal production > 300302 Animal management @ 100%
SEO Codes:	10 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 1001 Environmentally sustainable animal production > 100101 Management of gaseous waste from animal production (excl. greenhouse gases) @ 100%
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