This month’s feature collection showcases three Board Invited Reviews exploring the biology of lactation from three different perspectives. These include the impact of circadian rhythms on production efficiency, the impact of early heat stress on future cow performance, and a holistic look at how extending lactation length impacts the dairy cow’s whole production cycle and management.
Like all mammals, cows show seasonal and daily physiological and behavior variations. Metabolic and reproductive status interact, affect these variations, and are manifested in the daily and seasonal rhythms of milk yield and composition. Our featured infographic highlights a review that examines the current understanding of the circadian clocks that underlie these daily and seasonal variations. This paper discusses how the knowledge of these interactions may help to develop management practices that maximize the production efficiency of dairy cows (Casey and Plaut, 2022).
Also featured this month is a review of how in utero heat stress impacts the development of the dairy heifer’s mammary glands. In utero heat stress results in smaller mammary glands and fat pads on a per body weight basis. The authors discuss the potential impact on the future productive capacity of mature cows (Dado-Senn et al., 2022).
The third featured review takes a close look at the impact of extending the lactation length of the dairy cow on the management of health and fertility. This review takes a comprehensive view of what is known about extended lactation and its consequences on milk production, life cycle, and management of the cow. In addition, the authors examine the economic and environmental impact of these decisions on the farm (van Knegsel et al., 2022).
Literature Cited
- Casey, T., and Plaut K.. . 2022. Circadian clocks and their integration with metabolic and reproductive systems: Our current understanding and its application to the management of dairy cows. J. Anim. Sci. 100:skac233. doi: 10.1093/jas/skac233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dado-Senn, B., Field S., Davidson B., Dahl G., and Laporta J.. . 2022. In utero h yperthermia in late-gestation derails dairy calf early-life mammary development. J. Anim. Sci. 100:skac186. doi: 10.1093/jas/skac186. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Knegsel, A., Burgers E., Junnan M., Goselink R., and Kok A.. . 2022. Extending lactation length: Consequences for cow, calf and farmer. J. Anim. Sci. 100:skac220. doi: 10.1093/jas/skac220. [DOI] [PMC free article] [PubMed] [Google Scholar]