@conference {4189,
	title = {BRIEF COMMUNICATION: Effect of heat load on milk yield in grazing dairy cows},
	booktitle = {Hamilton},
	volume = {85},
	year = {2025},
	pages = {45-48},
	address = {Hamilton},
	abstract = {<p>Summer heat load in dairy cows is recognised as a potential stressor to animal comfort, however, the effects of heat load on production remains to be fully elucidated. The economic case for farmers to invest in improved heat mitigation could be strengthened if the cost of head load on milk yield is better understood. We explored the interactive effects of weather variables on milk production in two commercial dairy farms that were equipped with a weather station and milking machinery able to measure daily yields at cow level. The study was conducted in the Waikato, over the 2024-25 summer period and included data from 1,304 Holstein-Friesian and Holstein-Friesian-Jersey crossbred cows. Generalised Linear Mixed Models were used to determine the effect of weather on milk yield. Results indicated declines in milk yield were associated with higher temperatures, and this effect was greater under high humidity or high solar radiation conditions.</p>
},
	keywords = {dairy cow, Heat stress, milk yield, weather},
	author = {C. Reed and G. Chambers and J.P. Edwards and J. Jago and K.J. Verhoek}
}
@conference {4180,
	title = {BRIEF COMMUNICATION: Whole-herd extended lactations in a pasture-based system: year one of a farmlet study},
	booktitle = {Hamilton},
	volume = {85},
	year = {2025},
	pages = {9-12},
	address = {Hamilton},
	abstract = {<p>Extended lactations (EL) can potentially improve labour efficiency, reduce numbers of non-replacement calves, and reduce cow attrition. A 2023-24 farmlet study compared an EL system whereby half of the cows calved each spring with approximately 24-month calving intervals versus a Control system where all cows calved each spring with approximately 12-month intervals. The EL system produced more milksolids (MS) than Control (1,231 versus 1,182 kg/ha, respectively) from more days in milk (average of 308 across the two herds versus 251 days per cow, respectively) while consuming more supplementary feed (818 versus 621 kg DM/cow, respectively). Cows in EL produced on average 370 kg MS/cow over 304 days of lactation during the season, from a total of 855 kg MS/cow produced over a 600-day lactation. This study has shown the potential viability of this EL system and the data can be used to evaluate impacts on profitability and the environment.</p>
},
	keywords = {dairy cattle, extended lactation, New Zealand},
	author = {L.J. Farrell and J.P. Edwards and C.B. Glassey and Y. Lopez-Moreno and E Rauhala and C.R. Burke}
}
