Estimation of maximum thermo-hygrometric index thresholds affecting milk production in Italian Brown Swiss cattle

Abstract

It is known that heat stress affects dairy cow performance in multiple ways: physiological, behavioral, reproductive, and productive. The aim of the present study was to determine if a threshold of temperaturehumidity index (THI) exists for multiple milk production traits (milk yield, fat-corrected milk, protein and fat yield and percentage, energy-corrected milk, cheese production, and cheese yield) in Italian Brown Swiss dairy cows from the period 15 d before the day of the Italian Breeders Association test-day sampling. A 10yr data set (2009-2018) containing 202,776 test-day records of 23,296 Brown Swiss cows was matched with the maximum THI. In all parities considered, no THI thresholds were observed for milk yield in Brown Swiss. In contrast, a THI threshold of 75 was identified for fat-corrected milk. No THI threshold was found for fat percentage, but fat yield showed the highest THI thresholds in cows of first and second parity. Protein yield and cheese production were affected by heat stress with average THI threshold of 74. The THI thresholds identified indicate that the Brown Swiss breed has higher thermal tolerance versus literature values reported for Holstein cows. As THI rises, Brown Swiss cows tend to produce the same volume of milk, but with a decreasing quality with regard to components. Further study is necessary to estimate the genetic component of heat tolerance, in Brown Swiss cattle, considering that the correct estimation of THI thresholds represents the first step to identify components that could be included in selection procedures.

Seasonal effect on milk productivity and cases of mastitis in Ukrainian Brown Swiss Cows

“…It is known that periods of summer heat are accompanied by the HS in cows (Maggiolino et al, 2020). Under conditions of metabolic stress associated with the postpartum period (Sordillo & Raphael, 2013), dairy cattle also suffer from oxidative stress accompanied by tissue and cell damage (Sordillo & Aitken, 2009), including that of the udder (Tao et al, 2018).…”

“…As THI increases, the milk yield, fat and protein content reduce in dairy cows (Bernabucci et al, 2015;Amamou et al, 2019). Maggiolino et al (2020) report that an increase in THI per unit above the threshold value for Swiss cows was accompanied by a decrease in milk yield within the range from 0.38 to 1.00 kg/ day per cow. The established THI threshold values for milk yield, milk fat and protein content indicate that Swiss cows have higher heat resistance compared to the literature values for Holstein cows (Heinicke et al, 2018).…”

“…For example, for them the loss was 0.41 kg/day at THI values slightly higher than 69 units (Bouraoui et al, 2002); from 0.43 to 1.27 kg/day at THI values exceeding 70 units (Bernabucci et al, 2014), and even at THI values slightly higher than 55 units -by 0.13 kg/day (Amamou et al, 2019). It is revealing that as THI grows, Swiss cows tend to produce the same amount of milk, but with a deterioration in the quality of the components (Maggiolino et al, 2020).…”

“…Thus, a comprehensive understanding of the factors affecting the welfare of dairy cattle, including climatic and economic ones will allow us to develop adequate strategies to improve housing conditions and maintain animal productivity and product quality with increasing weather variability (Maggiolino et al, 2020).…”

Effect of Heat Waves on Some Italian Brown Swiss Dairy Cows' Production Patterns

“…Consequently, the supposed climate scenario may have some negative consequences from a different point of view: health, welfare, and overall efficiency. Heat stress increases the risk of production losses (Bernabucci et al, 2014;Dahl et al, 2019;Maggiolino et al, 2020), infections (Olde Riekerink et al, 2007), and mortality (Vitali et al, 2015).…”