Florida researchers began a generational study in 2007 that is still years in the making. It all began with the investigation of the impact of heat stress on dry cows to measure changes that might occur to the calf incubating inside the hot dam, like a crock pot.

In addition to seeing negative production impacts on mama, the researchers began to measure numerous changes in the damaged calf coming out of the heat stressed dry cow. This month’s edition, we’ll be interviewing Dr. Jimena Laporta, of the University of Wisconsin, to better understand the physiological changes of the calf that results in lost production for her entire life. She and her team measured changes in mammary and adrenal gland development.

Several separate papers have been peer reviewed over the 17 years of research. Many are linked at the bottom of the show notes for additional reference.

Listen in to understand how heat stressed dry cows can destroy your favorite cow families’ production records.

This month features two released paper titled: (1) Carry-over effects of maternal late-gestation heat stress on granddaughter’s growth and mammary gland development (ck out histology – Fig 1&2) (2) Programming effects of intrauterine hyperthermia on adrenal gland development

Topics of discussion

1:58 Introduction of Dr. Jimena Laporta 4:17 Describe the experimental design 6:19 Description of the generations impacted through in utero heat stress 7:29 The biological link between the grand dam and the grand daughter (F2) 9:16 Eight years of research to collect multigenerational data 10:39 F1 management in WI beginning at 8 weeks 12:00 F1 mammary implications following heat stress while developing in utero 13:32 F2 calves – changes as a result of dam’s exposure to heat stress while developing in utero 15:01 Early mammary growth 15:32 What is causing these differences in F2 17:35 Lumen space and estrogen receptors 19:06 Summary of 3 generations of damage 20:34 Should I build a lactating barn or dry cow barn? 22:39 The Adrenal Gland 27:38 Adrenal effect on inflammation 28:56 What do you want Boots on the ground dairyman to know

Background Information: Temperature Humidity Index (THI) 2020 Dairy Science Digest Podcast interview 2020: Late-gestation heat stress impairs daughter and granddaughter lifetime performance (economic impact) 2016: In utero heat stress decreases calf survival and performance through the first lactation

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