Effect of heat stress amelioration through open-ridge ventilated thatched roof housing on production and reproduction performance of crossbred Jersey cows

Our plain-English summary of Effect of heat stress amelioration through open-ridge ventilated thatched roof housing on production and reproduction performance of crossbred Jersey cows, by D.K. Mandal, A. Mandal, C. Bhakat, et al (Tropical Animal Health and Production, 2021).

The study

• Authors: D.K. Mandal, A. Mandal, C. Bhakat, T.K. Dutta
• Journal: Tropical Animal Health and Production
• Published: 2021;53(1):144
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The present study was conducted to assess the impacts of loose house roofing designs and materials on modulation of micro-climate of the cow shed and its influences on production and reproduction performance of lactating crossbred Jersey cows. The control group (T0) was kept in a traditional single-slope asbestos roof shed and treatment group (T1) at a specially designed open-ridge ventilated, double-slope thatch roof shed. Lactation stage, average daily milk yield, and average parity at the beginning of the experiment were kept similar between T0 and T1 cows. The specifically designed T1 shed had significantly (P < 0.05) lower temperature, humidity, and thermal humidity index as compared to the traditional shed (T0). The T1 shed was cooler and more comfortable than T0. Housing significantly (P < 0.05) influenced cardinal physiological parameters of resident cows. Body temperature, pulse rate, respiration rate, and discomfort index were significantly (P < 0.05) higher in T0 as compared to those in T1 cows. Improved housing significantly (P < 0.01) influenced milk yield, composition, quality, and udder health of cows. Daily milk yield depending on parity, monthly milk yield, milk fat, SNF, and protein were significantly (P < 0.01) higher in T1 than those in T0 cows. The milk somatic cell count, modified California mastitis test score, electrical conductivity, and pH of milk samples of T0 cows were significantly (P < 0.0) higher than those of T1. Effect of housing type, parity, and interaction of housing × parity did not cause any significant (P > 0.05) differences in reproductive traits such as service period, break period, calving interval, pregnancy rate, and other cow fertility parameters. Post-partum body condition score and body weight loss did not differ significantly (P > 0.05) between the two groups; however, more loss occurred in T0 than T1. The estimated net profit from housing of cows (N = 20) in a comfortable shed was 2200 kg milk per annum, i.e., 110 kg/cow/annum. The study concluded that a central open-ridge ventilated, double-slope thatched roof design created a favorable micro-environment and it significantly affected cows' comfort index; thermo-comfortable housing significantly reduced the heat stress-oriented drop in milk yield and decline in milk composition, and improved udder health and other milk production traits; however, its impact was non-significant on reproduction and fertility traits in Jersey crossbred cows.

In plain English

This study did not examine the health effects of asbestos. It was a dairy-cow housing experiment in India in which the comparison shed had an asbestos roof. From 2017 to 2019, at a research station in Kalyani, West Bengal, 80 Jersey crossbred cows were divided into two comparable groups of 40. One group lived in a traditional single-slope asbestos-roof shed fitted with ceiling fans. The other lived in a double-slope thatched (paddy straw) roof shed with central open-ridge ventilation and no fans. The thatched shed was cooler, for example 1.1 to 1.84 °C cooler in the mornings. Cows in the asbestos-roof shed had significantly higher rectal temperature, pulse and breathing rates. Cows in the thatched shed gave more milk, about 520 g per day more, and had better udder-health test results. Fertility measures did not differ significantly between the groups. The authors concluded that the thatched design improved cow comfort, milk production and udder health, but not reproduction.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Comparative housing experiment in dairy cows, run as three separate trials whose data were pooled; control group (T0) in a traditional asbestos-roof shed, treatment group (T1) in a thatched-roof shed
• Who was studied: 80 healthy Jersey crossbred cows (40 control, 40 treatment) at ICAR-National Dairy Research Institute, Eastern Regional Station, Kalyani, West Bengal, India, 2017 to 2019
• Exposure: Type of housing: a traditional single-slope asbestos-roof shed with four ceiling fans (control, T0) versus a double-slope paddy-straw thatched roof shed with central open-ridge ventilation and no fans (treatment, T1). Asbestos fibers and their health effects were not studied.
• Main results:
  • Morning temperature inside the thatched shed (T1) was lower than in the asbestos-roof shed (T0) by 1.1 to 1.84 °C across months; afternoon temperature was lower by 1.13 to 2.61 °C
  • Rectal temperature, pulse rate and respiration rate were significantly higher (p less than 0.05) in cows in the asbestos-roof shed (T0) than in the thatched shed (T1), both morning and afternoon
  • Cows in the thatched shed (T1) produced more milk than cows in the asbestos-roof shed (T0): 520 g per day more (total daily yield 7.99 versus 7.47 kg in Table 3)
  • In milk from cows in the thatched shed (T1), somatic cell count, mastitis test score, electrical conductivity and pH were 3, 17, 11 and 3% lower than in milk from cows in the asbestos-roof shed (T0)
  • Housing type, parity and their interaction caused no significant differences (P greater than 0.05) in reproductive measures such as service period, break period and calving interval
  • Overall conception rate was the same in both groups (text gives 67.50%; Table 8 prints 67.25, 27 of 40 cows in each group)
  • Post-partum body weight and body condition score changes did not differ significantly between groups, although cows in the asbestos-roof shed (T0) lost more
  • The authors estimated a net gain of 2200 kg of milk per year for a 20-cow thatched shed, or 110 kg per cow per year
• The authors' conclusion: The authors concluded that the open-ridge ventilated thatched roof design created a more comfortable environment than the traditional asbestos-roof shed and improved milk yield, milk composition and udder health, but had no significant effect on reproduction and fertility.
• Limitations the authors state:
  • The authors state that no experiment was done to estimate negative energy balance in the two groups
  • The authors state that estimating the net economic benefit needs more data and further studies
  • The authors suggest that older (multiparous) cows may have been familiar with asbestos-roof sheds, having been raised in them since birth

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