The effect of low and high barn temperatures on behaviour and performance of Holstein dairy cows

The experiment was carried out at the University Training Farm in Žabčice (the Czech Republic; location 49°0’51.081”N, 16°36’14.848”E, 179 m.a.s.l) over the period of one year (1st July to 30th June). The assessment of temperature impact was based on data from 16 hottest days (H) and 16 coldest days (L). The experimental group consisted of 70 cows in various stage of lactation (30d–210d) and parity (1–8). The cows were housed in a section (one quarter) of a free-stall barn with 77 stalls in three rows. Row A was located peripherally, close to the side wall, row B was in the middle and row C was situated centrally, close to the feed table. The cows were observed weekly on the same day at 9.00 a.m. The microclimate characteristics were recorded daily: temperature in hot (H) resp. cold (L) period was in average 27.1°C resp. – 1.47 °C, and relative humidity 54.4 % resp. 77.3 %, and THI 75 resp. 33.Behaviour was described by a number of cows standing or lying down, number of cows lying down on their left or right side and row preference (A, B, C) in the resting area. Cow Comfort Index (CCI – a number of cows lying down at given time) was calculated. A total of 1587 observations were analysed. A number of cows lying down (922) was significantly higher than that of standing cows (665). Milk production was significantly higher in hot (H) period (by 1.0–1.7 kg). There was an interaction in milk production between period and standing. In H period the standing cows produced more milk, in L period vice versa. The cows with non-significant tendency towards left-side laterality produced more milk (by 1.2 kg). No interaction was found between period and laterality for milk production. All the observed parameters significantly differed between rows A, B and C. Row A was the most preferred, the cows preferring it were young (low number of lactation) with greatest milk production. The cows in row C had the lowest milk production and were in late lactation. The interaction was found between period and row affected number of lactation (P < 0.01) and number of cows (P < 0.05). In H period the row A was preferred by older cows (high number of lactation), while in L period it was preferred by younger cows. The cows in H period used row C less while in L period they preferred it.