Effect of THI on milk coagulation properties of Holstein-Friesian dairy cattle

Abstract

-The objective of this study was to evaluate the effect of temperature-humidity index (THI) on the milk coagulation properties of Holstein-Friesian dairy cattle from northeast part of Italy. A total of 592 individual milk samples from six dairy herds were evaluated. The milk coagulation properties traits analysed were milk rennet coagulation time and curd firmness, as well as the fat, protein, and casein contents, pH, milk aptitude to coagulate (IAC), and the somatic cell count. The THI was determined during the periods of sample collection. The THI results showed that values of up to 75 did not significantly change the IAC values; however, when the THI values were above 75, the IAC decreased significantly. The control of THI can be used to guarantee appropriate milk coagulation properties.

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

“…In fact, lactating cows are most sensitive to thermal stress, due to the metabolic heat load produced from nutrient digestion and milk synthesis, which is proportional to milk yield (Nasr and El-Tarabany, 2017). The relationship between high milk yield and heat tolerance has been studied in Holstein cows by several authors (Aguilar et al, 2010;Bernabucci et al, 2014;Beux et al, 2017;Amamou et al, 2019) and it is well demonstrated that the level of milk yield negatively affects thermal tolerance (Ravagnolo and Misztal, 2002;Wheelock et al, 2010;Bernabucci et al, 2014), but few studies have been conducted in Brown Swiss cows, perhaps due to the perceived higher heat tolerance versus Holstein cows, although those studies were conducted measuring the increase of rectal temperature under heat stress, and not observing productive traits (Correa-Calderon et al, 2004). The effect of heat stress on dairy cows is of growing interest as an attempt to anticipate problems related to global warming (Dikmen and Hansen, 2009).…”

“…Different methods have been applied to describe environmental conditions using THI, such as Estimation of maximum thermo-hygrometric index thresholds affecting milk production in Italian Brown Swiss cattle average THI per hour, average per day, or average per daytime or nighttime part of the day (Cincović et al, 2011;Herbut and Angrecka, 2018). Some studies report that maximum daily THI values were more highly correlated with productive traits relative to other THI indices (Ravagnolo and Misztal, 2002;Bernabucci et al, 2014;Beux et al, 2017). Temperature-humidity index thresholds or classes were suitable for estimating the intensity of thermal discomfort (Endres and Barberg, 2007;Allen et al, 2015), and defining a THI of 72 is the threshold in Holstein cows for the initial limit for heat stress and consequently the first decrease in milk production (Heinicke et al, 2018).…”

“…However, it has been shown that a THI in the range of 62 to 69 can reduce milk yield (Zimbelman et al, 2009;Bernabucci et al, 2014;Lambertz et al, 2014). Most of the existing studies examining the effects of heat stress on behavioral (De Palo et al, 2006;Uzal Seyfi, 2013;Allen et al, 2015;Herbut and Angrecka, 2018;Heinicke et al, 2018Heinicke et al, , 2019, physiological (Dikmen and Hansen, 2009;Amamou et al, 2019;Jeelani et al, 2019), productive (Hammami et al, 2013;Bohlouli et al, 2013;Bernabucci et al, 2014), and milk processing characteristics (Beux et al, 2017) were carried out on Holstein cows, probably because it is the predominant breed of dairy animal globally, whereas less is known about breed differences in thermal tolerance. To date, no studies are available dealing with heat stress effects and THI thresholds in Brown Swiss dairy cows.…”

Evaluation of enzymatic coagulation of milk from a herd of Holstein cows in three periods of the year / Avaliação enzimática da coagulação do leite de um rebanho de vacas Holandesas em três períodos do ano

“…According to Cecchinato et al (2011) in slow-coagulating milks curd formation has less time to stiffen, and it is, therefore, more fragile, resulting in protein and fat losses to the serum at the cutting and press stages, reflecting yield reduction. Besides, the dynamic oscillatory analysis presented at Figure 1 and Table 1 by According to (Beux et al, 2017) the influence of the milk collection in different periods of the year on milk coagulation capacity can be affected by changes in temperature and humidity throughout the year. However, these authors reported that for values of temperature and humidity (THI) below 75, milk does not present significant changes regarding this characteristic.…”

Correlations between Environmental Factors and Milk Production of Holstein Cows

“…Milk yield and milk components can also be indicators of animal comfort, since they are affected by the physiological state of the organism subject to high temperature [13]. Many researchers have taken into account data of meteorological stations located near farms when assessing the impact of weather on animal productivity [14,15]. Such an approach is acceptable when evaluating the effect of heat on animals, not only during grazing but also in uninsulated barns in which the microclimate is similar to the state of the environment [16].…”