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Climate Control and Production in Small Ruminants
A comprehensive analysis of thermal impact and engineering solutions for the sheep and goats sector in Spain.
The Climate Challenge in the Iberian Peninsula
Spain is positioned as one of the most vulnerable regions to climate change in the European Union. With a recorded thermal increase of approximately 0.5 °C per decade [Ref. 23], the livestock sector faces unprecedented environmental pressure. For small ruminants, thermal stress is not only an animal welfare issue but a critical factor that reorganizes their basal metabolism and drastically reduces dry matter intake [Ref. 12, Ref. 15].
High-production breeds, such as the Assaf in sheep or the Murciano-Granadina in goats, are especially sensitive due to the high metabolic heat generation associated with lactation [Ref. 4]. The implementation of environmental control systems has become a necessity to ensure the profitability of modern farms [Ref. 33].
Critical Risks
- ● Temperature: Exceeding 25-28°C nullifies the thermoneutral zone [Ref. 3].
- ● Humidity: Hinders heat dissipation by evaporation [Ref. 5].
- ● Air Quality: Accumulation of NH3 and pulmonary risk [Ref. 25].
The Temperature and Humidity Index (THI)
The THI is the standard metric for assessing thermal risk. Values above 72 trigger physiological defense responses in small ruminants [Ref. 15]. Thom’s formula allows for precise calculation of this index:
Where T is Temp (°C) and HR is Relative Humidity in decimal [Ref. 5].
Milk Production
Reduction of 5% to 15% in daily volume and drop in solids (fat and protein) [Ref. 5, Ref. 41].
Reproduction
Early embryonic mortality increases by 20% under severe heat stress [Ref. 15, Ref. 31].
-18.5%
Conception Success
Animal Health
Higher frequency of pneumonia and risk of respiratory alkalosis [Ref. 25, Ref. 43].
- Increase in somatic cells.
- Higher incidence of clinical mastitis.
Adiabatic Cooling Systems
Environmental engineering allows temperature drops of 6°C to 10°C through water evaporation. This process is highly efficient in the dry climates predominant in the interior of Spain [Ref. 12, Ref. 13].
Capture of warm outside air using forced fans.
Air passage through wet cellulose panels (evaporation).
Injection of climatized air into the resting area.
Design Parameters [Ref. 12]
Air Speed
Renewal
Space/Animal
Feeder/Animal
Diet Adaptation
To minimize the increase in heat from ruminal fermentation, it is recommended to shift the supply of the total mixed ration (TMR) to the cooler hours of the day. 70% of the intake should occur during nighttime hours [Ref. 5, Ref. 15].
- Bypass Fats: Increase caloric density with low metabolic heat [Ref. 5].
- Effective Fiber: Adjustment of NDF to stimulate saliva and prevent acidosis [Ref. 43].
- Fresh Water: Constant availability at less than 20°C [Ref. 32].
Economy and Profitability (ROI)
Climate control is an investment that can be amortized through the stability of annual production [Ref. 33].
CAP Aid
The PEPAC 2023-2027 subsidizes up to 40% of these technological investments [Ref. 34].
Annex: Bibliographic References
[Ref. 3] Hafez, E. S. E. (2013). Reproduction in Farm Animals.
[Ref. 4] Llonch, P., et al. (2018). Review of heating systems in small ruminant farms.
[Ref. 5] Silanikove, N. (2000). Effects of heat stress on small ruminant production.
[Ref. 12] Almería, S. (2020). Manual of Good Practices: Animal Welfare. MAPA.
[Ref. 13] Bucklin, R. A., et al. (2012). Methods to Relieve Heat Stress in Ruminants.
[Ref. 15] Sevi, A., et al. (2009). Management strategies for heat stress in sheep.
[Ref. 23] AEMET. (2023). Report on the state of the climate in Spain 2022.
[Ref. 24] INTEROVIC. (2024). Animal Welfare Seal AWIS.
[Ref. 25] Mitchell, D. (2022). Respiratory physiology in heat-stressed livestock.
[Ref. 31] Ramon, M., et al. (2016). Heat stress impact on fertility in Spanish breeds.
[Ref. 32] Chaucheyras-Durand, F., et al. (2008). Mode of action of live yeasts in the rumen.
[Ref. 33] Wolfenson, D., et al. (2018). Economic analysis of cooling systems.
[Ref. 34] PEPAC. (2024). Strategic Plan of the CAP 2023-2027.
[Ref. 41] Salama, A. A. K., et al. (2014). Effects of heat stress on milk fatty acid profile.
