The Slick Holstein as an alternative to cope with heat stress in tropical dairy operations

Keywords: Dairy Cattle, Climate Change, Slick Gene, Holstein


Heat stress is a significant challenge to dairy production in most parts of the world. Puerto Rican Criollo cattle carry the Slick (SL) gene that results in short lustrous hair, conferring them with superior heat tolerance that makes them a valuable genetic resource in dairy breeding programs aiming at achieving resiliency upon the uncertainty of climate change.  The SL gene has been part of the Puerto Rican dairy cattle genetic pool long enough that we have registered SL Holsteins with ancestry percentages greater than 93%.  We documented milk production throughout the lactation cycle and calving intervals (CI) of SL registered Holstein cows in El Remanso Dairy Farm, in Camuy, Puerto Rico (18.4839° N, 66.8450° W).  Official production and reproductive data from the Dairy Records Management System ( was obtained and used to compare the production of 17 SL hair registered Holstein cows with 68 wild-type (WT) Holsteins.  Milk production was analyzed using Proc GLIMMIX of SAS (SAS University Edition, 2018) and a Tukey test was conducted to analyze milk production during the hot period using a model that included genotype (SL and WT), stage of lactation, and lactation number (1, 2 or ≥ 3) as fixed effects.  Tukey test analysis were also performed comparing the CI between 4-12 SL and 4-12 WT Holsteins with data from 2013-2016 (number of cows varied by year).  Average milk production for SL and WT Holsteins was 16.59 ± 0.94 and 14.83 ± 0.41 kg/day (p=0.746).  SL Holsteins showed a shorter CI than their WT contemporaries with an average of 14.42±0.13 versus 16.06±0.08 (p=0.001).  Under the hot and humid conditions of Puerto Rico, SL Holstein dairy cows perform reproductively better than WT Holsteins. Therefore, the SL gene may be an appropriate adaptive strategy to support an efficient dairy industry within a warmer global climate.


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How to Cite
Ortiz-Uriarte, Bianca, Natalia Rosa-Padilla, Rafael López-López, Jaime Curbelo-Rodríguez, Verónica Negrón-Pérez, and Guillermo Ortiz-Colón. 2020. “The Slick Holstein As an Alternative to Cope With Heat Stress in Tropical Dairy Operations”. Latin American Archives of Animal Production 28 (3-4), 145-53.