Climatic effects on milk production traits and somatic cell score in lactating Holstein-Friesian cows in different housing systems

Abstract

The objective of this study was to compare the effect of the temperature-humidity index (THI) on milk production traits and somatic cell score (SCS) of dairy cows raised in 4 different housing systems: (1) warm loose housing with access to grazing (WG), (2) warm loose housing without access to grazing (WI), (3) cold loose housing with access to grazing (CG), and (4) cold loose housing without access to grazing (CI). For each of the 4 housing systems, 5 farms with a herd size of 70 to 200 lactating cows in Lower Saxony, Germany, were studied. Ambient temperature and relative humidity were recorded hourly in each barn to calculate THI. Milk production data included 21,546 test-day records for milk, fat, and protein yield, and SCS. These data were associated with the average THI of the 3 d preceding the respective measurement, which was divided into 6 classes (<45, ≥45 to <50, ≥50 to <55, ≥55 to <60, ≥60 to <65, and ≥65). Furthermore, bulk milk samples including the fat and protein percentage, and SCS taken 4 to 6 times per month were associated with the average and maximum THI of the 3 d before sampling. Data were recorded from April 2010 to March 2011. In each of the housing systems, monthly THI values above 60, indicating heat stress, were recorded between June and September, with higher values in WI and WG. In all systems, fat-corrected milk, fat, and protein yields of the test-day records decreased in tendency from 60 ≤ THI<65 to THI >65. In WI and CI, values for SCS were greater in the class THI > 65 than in 60 ≤ THI<65, whereas no difference between any of the THI classes was found in WG and CG. The fat and protein percentage of the bulk milk samples decreased with increasing 3-d maximum THI in all 4 systems, whereas the SCS increased with increasing 3-d average THI. In conclusion, negative effects of heat stress conditions under a temperate climate on milk production traits and SCS were found, although a housing system being superior to the other systems in altering heat stress effects was not identified.

Dairy cattle in a temperate climate: the effects of weather on milk yield and composition depend on management

“…Bouraoui et al, 2002;Gantner et al, 2011;Bruegemann et al, 2012;Hammami et al, 2013). Our results also agree with those of Lambertz et al (2014), who reported a more marked decline in total protein yield with increasing THI in cows with access to pasture than those without. The increase in milk protein content with increasing WS when animals were outdoors was probably owing to the action of wind in alleviating heat stress, while an increasing level of radiant heat from sunshine would have contributed to heat stress.…”

“…Although recent studies have used summaries of the 3 days preceding milk sampling to describe weather conditions (e.g. Lambertz et al, 2014), our results suggest HF = high forage; LF = high forage; S = select; C = control. Significant differences between levels are indicated in Table 3.…”

“…Cattle that were rotated between an indoor and outdoor environment responded according to the prevailing environment and produced more milk when they were indoors than outdoors. Similarly, grazing cows produced less fat-corrected milk than animals without access to grazing in another study (Lambertz et al, 2014). We assume that these results are largely a consequence of differences in diet: animals maintained indoors in our study received ad libitum TMR with some forage, while those outdoors ate mainly grass.…”

“…Similar to milk yield, fat content was highest at moderate WSs. Most previous studies also report a decrease in the proportion of fat in milk (Bouraoui et al, 2002;Hammami et al, 2013;Smith et al, 2013) or total milk fat (Lambertz et al, 2014) under conditions of heat stress or increasing temperature, although others found no effect (Knapp and Grummer, 1991;Wheelock et al, 2010). While an increase in the number of sunshine hours was associated with an increase in milk yield in cows outdoors and a decrease in milk yield in cows indoors, the inverse was true for fat content.…”

Access to shade changes behavioral and physiological attributes of dairy cows during the hot season in the subtropics

“…The increase in milk consumption and world interest in increasing animal welfare raises concerns on how to improve milk production and minimize environmental aspects that may cause discomfort to dairy cows (Lambertz et al, 2014). Cattle in tropical and subtropical climates, especially those raised at pasture, can be exposed to high solar radiation, air temperature and relative humidity, as well as rain and wind speeds above their thermal comfort zone.…”