Evaluation of heat stress on Tarentaise and Holstein cow performance in the Mediterranean climate.
This study was undertaken to first quantify the effect of heat stress on milk yield and components of Tarentaise in comparison to Holstein cows. A dataset of 16,143 monthly individual records of production traits was collected for 435 Tarentaise and 543 Holstein cows from 21 farms in Tunisia (2009 to 2014). This dataset was merged with meteorological data from 5 public stations relative to the 21 farms. The temperature-humidity index (THI), calculated as a combination of ambient temperature and relative humidity, was used to characterize heat stress. When the THI increased from an average value of 53.7 in winter to 75.4 in summer, the Holstein and Tarentaise cows decreased their milk production by 0.93 and 0.15 kg/day, respectively. Milk fat, protein, and urea content decreased similarly in both breeds (-2.20 g/kg, -1.40 g/kg, and -14 mg/L, respectively), and the milk somatic cell count increased for Holstein cows (+352,000/mL) while decreased for Tarentaise cows (-160,000/mL). The second aim of this study was to describe the relationship between the variations of the milk yields between the summer and the winter (Δ milk yields) and some barn characteristics during the hot season. A survey carried out on 19 of the 21 previous farms permitted to conclude that the closed buildings led to a higher decrease in milk yield between the summer and winter than the open buildings (-1.13 vs. -0.27 kg/day). A metallic roof had a more negative impact on Δ milk yields than the other roof types (-1.04 vs. -0.15 kg/day).
INRA, UMR1213 Herbivores, F63122, Saint-Genès-Champanelle, France. bellagi.rahma@yahoo.com.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France. bellagi.rahma@yahoo.com.|INAT, Département des ressources animales, halieutiques et technologies agro-alimentaires, 1082, Tunis, Tunisia. bellagi.rahma@yahoo.com.
Rahma
http://orcid.org/0000-0002-1134-9342
R
Bellagi
INRA, UMR1213 Herbivores, F63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
Bruno
B
Martin
INRA, UMR1213 Herbivores, F63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
Chantal
C
Chassaing
INAT, Département des ressources animales, halieutiques et technologies agro-alimentaires, 1082, Tunis, Tunisia.
Taha
T
Najar
INRA, UMR1213 Herbivores, F63122, Saint-Genès-Champanelle, France.|Clermont Université, VetAgro Sup, UMR1213 Herbivores, BP 10448, F-63000, Clermont-Ferrand, France.
Dominique
D
Pomiès
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000503:physiopathology*; D002980:Climate; D005223:Fats / Q000032:analysis; D005260:Female; D018882:Heat Stress Disorders / Q000503:physiopathology* / Q000662:veterinary*; D006799:Housing, Animal; D006813:Humidity; D007774:Lactation; D019083:Mediterranean Region; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis; D013696:Temperature; D014508:Urea / Q000032:analysis
D005223:Fats; D008894:Milk Proteins; D014508:Urea
Barn characteristics; Heat stress; Production traits; Tarentaise cow; Temperature-humidity index