Which Of The Following Is A Sign Of Heat Stress In Animals?

How to detect early on signs of heat stress in ruminants

Apr xvi, 2021

Long before milk production or growth rates are affected, heat stress can be detected and recognized by changes in creature behavior. Detecting the signs of heat stress as early as possible is essential to preserving its total production and health potential by adjusting the heard management. Here are some tips.

Watch the weather

Table 1: THI table (from Burgos & Collier)

The temperature-humidity index (THI) is a common indicator of heat stress risk (tabular array i). That'south because the temperature is important but also the air relative humidity level, which exacerbates the effect of heat.

The THI in the befouled could exist higher than the THI based on meteorological data. On the other hand, solar radiation could increase the actual estrus stress in grazing animals. By placing a thermo-hygrometer — or a new generation of sensors that continuously monitor THI within the barn, — shut to the animals, producers tin monitor and anticipate rut stress risks.

The negative impact of oestrus stress is linked to the THI level and to the duration of exposure, both in terms of the number of hours/24-hour interval and the number of sequent days of stress.

• For dairy cows: the estrus stress threshold is as low equally 68 (Burgos and Collier, 2011). This means that, for example, at 50% humidity, cattle begin to experience the negative furnishings of heat stress at 22°C.
• For beef cattle: the estrus stress threshold is estimated at 72. This means that at 50% humidity, cattle are exposed to heat stress at 25°C.
• For pre-weaned calves: a rut stress threshold has been set at 78 (Kovacs et al., 2020)
• The thermal neutral zone for sheep is betwixt 12-32°C and for goats is between 12-24°C. The actual threshold for estrus stress in dairy sheep and goats, based on THI, is more or less comparable to dairy cattle but can vary depending on breed, housing, and production organization.

Animal observation is key to detect early signs of heat stress

The first signs of moderate heat stress include:

• Shallow breathing
• Increased respiration rate
• Profuse sweating
• Reduced feed intake
• Reduced lying time: to increase heat dispersion, the brute will spend less fourth dimension lying quietly (and ruminating). Inquiry has shown a significant drop in lying time under the oestrus stress threshold.
• Decreased rumination activity: there is a correlation between rumination time and rumen function, hence the lowered product performance. In dairy cows, it has been shown that for each 10-point increment in the THI, daily rumination could be reduced by i hour and dairy production past two.7 kg/day (vi lbs.) (Haan, 2016). We estimated that a good target is to have 50-60% of dairy cows lying in their stalls ruminating at the aforementioned fourth dimension. Nether heat stress weather condition, rumination is suboptimal in l% of farms (Lallemand Animal Diet internal data, REI audits¹).
• Erratic feeding behavior: as digestion produces estrus, the animals will tend to eat less at the coolest hours of the solar day to reduce heat production.

Look out for signs of reduced rumen part

The post-obit signs tin indicate poor rumen office: decreased lying and rumination time, loss of saliva through panting, a reduction in repast frequency, and larger meal size, also known every bit "slug feeding." The experts at Lallemand can besides help producers measure rumen function on their operation¹ past assessing signs such as:

• Manure color and consistency are effective means to appraise rumen function. The presence of undigested grain or cotton seeds, for example, are signs of sub-optimal rumen part, where precious (and expensive) nutrients are non beingness fully digested by the beast.
• Locomotion. Lameness tin can be a sign of poor rumen function and Sub Acute Ruminal Acidosis (SARA) events. Estrus stress can exacerbate poor rumen fermentation and office and negatively touch on brute behavior resulting in even worse locomotion scores and a higher incidence of lameness.

In small-scale ruminants, oestrus stress has a large bear upon on rumen health too.

Consequences on animal performances and wellness

Tabular array 2: Estimated associated milk loss according to the length of exposure to heat stress.

The reduced rumen function and lower feed intake atomic number 82 to a reduced energy supply, which impacts performance in all ruminant types:

• For dairy cows: milk yield and milk components are reduced. Milk loss is linked to both oestrus stress levels and duration of exposure: only iv hours exposure/day to depression heat stress levels already leads to a milk production decrease by 1.i kg/day (table 2).
• For dairy sheep and goats, the decrease in milk production depends on the breed, production level, and lactation phase. A reduction in milk production of 15% is possible (Cannas, 2007, Salama, 2014). In addition, the decrease in feed intake is frequently partially compensated by the mobilization of body tissue.
• For beef cattle: average daily gain drops with increased exposure to heat stress.

It has likewise been shown that heat-stressed animals experience increased oxidative stress combined with a lower antioxidant status. This could besides have a negative effect on fauna health, immune defenses, reproductive performance besides as meat quality.

Importance of prevention

In determination, it is crucial to discover the starting time signs of heat stress equally early on as possible, by monitoring both the surroundings and the animals. During a risky time, it is important to gear up the animals and support proper rumen part and rumen pH to help maintain the performance level. During hot atmospheric condition, information technology is essential to ensure a sufficient intake of cobweb in the nutrition and stabilize the rumen with the rumen-specific yeast Saccharomyces cerevisiae CNCM I-1077 (Levucell SC)— which was demonstrated to improve both food digestion and rumen efficiency (Fustini et al., 2013; Perdomo et al., 2020). Supplementation with this live yeast should be likewise connected in the period later on the heat stress event to support the recovery because the rumen buffer capacity is not yet sufficient directly after a heat stress event.

Nigh Lallemand Rumen Efficiency Investigation (REI) audit: The REI audit is a holistic approach based on the cess of a set of measurable indicators at the farm level. At that place are ix indicators in total, selected by integrating bibliography reviews, practical dairy farms surveys, and international good views, and validated in the field. These indicators are linked to dairy performance data, animal observations, manure observation, and environmental conditions (THI). This integrated method is an interesting determination-making tool every bit information technology enables the subcontract team and nutritionist to get a snapshot of a dairy herd status at different fourth dimension points and to evaluate the bear on of diet or herd management changes.

REFERENCES:

Burgos Zimbelman R. and. Collier R.J. Tri-Country Dairy Nutrition Conference, April nineteen and 20, 2011

Fustini Thousand., A. Palmonari, H. Durand, A. Formigoni and E. Grilli. 2013. Effect of Saccharomyces cerevisiae CNCM I-1077 (LEVUCELL SC) on rumen pH and milk production during heat stress. J. Anim. Sci. 91 (S2)/J. Dairy Sci. 96 (S1)

Kovács L, Kézér FL et al. Short communication: Upper disquisitional temperature-humidity index for dairy calves based on physiological stress variables. J Dairy Sci. 2020 Mar;103(3):2707-2710

Peana, I., Fois, G., & Cannas, A. (2007). Effects of rut stress and diet on milk product and feed and energy intake of Sarda ewes. Italian Periodical of Animal Scientific discipline, 6(sup1), 577-579.

Salama, A. A. K., Caja, Thou., Hamzaoui, Due south., Badaoui, B., Castro-Costa, A., Façanha, D. A. East., … & Bozzi, R. (2014). Different levels of response to heat stress in dairy goats. Small Ruminant Research, 121(1), 73-79.

Source: https://lallemandanimalnutrition.com/en/europe/whats-new/how-to-detect-early-signs-of-heat-stress-in-ruminants/

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