By Tatenda Dezah- Animal Nutritionist

The general perception of Climate Change to the modern day livestock farmer is alteration of geo-climatic patterns characterised by extreme weather events like unprecedented warming, changes in rainfall cycles and very low temperatures.

Climate Change is a principal threat to the sustainability of our planet.

The livestock sector is the most affected by climate variability and change due to its dependency on climatic parameters like rainfall and temperature.

As if it is not enough, climate is still changing and its impact expected to worsen the vulnerability of livestock systems, reinforcing existing risks on livestock and livestock production systems.

It is predicted that incessant Climate Change will exacerbate current stressors such as drought conditions, flooding events, pest and diseases incidences, animal heat-stress and deterioration and change in composition of grazing pastures which severely affect livestock production directly or indirectly.

Heat and Temperature Variations

Drought conditions are brought about by lengthy dry spells followed by erratic rains which cause flash floods.

Increased pest and disease incidences are induced by the favourable conditions presented by Climate Change for the proliferation of pathogens.

Animal heat-stress and the deterioration of grazing pastures are caused by the drought conditions mentioned above.

Semi-arid agro-ecological zones in Zimbabwe, and Africa at large, are more prone to the adverse effects of Climate Change because of pronounced dry periods and coupled with declining water availability.

Apart from Climate Change related diseases, extreme temperatures cause livestock to acclimate, a phenomenon  whereby animals forcibly adapt to the weather, which results in alteration of physiological functions including productive and reproductive efficiency as well as reduced feed intake owing to heat increment during  feeding.

Reduced feed intake means a reduction energy intake hence negative energy balance leading to retarded growth, reduced milk, egg and meat production compromising food and income security for livestock-based livelihoods.

Furthermore, heat stress reduces the immune responses in cattle, chickens and pigs.

Exposure to elevated ambient temperatures impoverishes semen quality decreasing fertility even in poultry, horse, donkey and rabbit males.

Females exposed to similar conditions experience poor ovarian follicle development and ovulation as well as reduction in embryo recovery.

Although the vulnerability of heat stress varies according to species, age, nutritional status and genetic potential, the overall effects are detrimental. 

Feeding the Livestock

Livestock systems in developing countries are extremely dynamic, driven by increasing populations and incomes creating growth in demand for livestock products, and this is projected to continue well into the future, although at a diminishing rate.

A consequence of this is the intensification of land use for the production of livestock feed.

With the adverse effects of Climate Change attacking crop production, the availability and price of livestock feed-grain is compromised due to the increased human-animal competition of cereals and oil seeds.

Moreover, the forage quality and quantity will be reduced resulting in diminishing productivity of the animals.

It’s a vicious cycle!

In addition to the direct impacts of a changing climate on the many aspects of livestock and livestock production systems, there are several indirect impacts that can be expected to impact livestock farmers in developing countries.

Climate Change and Human Health

One of the most significant of these is the impact on human health. As with livestock diseases, the changes shaped by Climate Change on infectious disease burdens may be sophisticated.

Impacts of Climate Change on malaria distribution, for instance, are likely to be largest in Africa and Asia, although Climate Change is not likely to affect malaria transmission in the least developed countries where the climate is already highly favourable for transmission.

In addition, Climate Change will have further influence on heat related mortalities and on the incidence of climate sensitive infectious diseases, and these may be significant.

Although Climate Change effects may have few direct impacts on other important diseases such as HIV/AIDS, climate variability impacts on food production and nutrition can affect susceptibility to HIV/AIDS as well as to other diseases.

HIV/AIDS is a major development issue facing sub-Saharan Africa: the epidemic deepens poverty, reverses human development achievements, worsens gender inequalities, erodes the ability of governments to maintain essential services, reduces labour productivity and supply and retards economic growth.

The HIV/AIDS issues concerning land use relate to reduced accessibility to labour, less capital to invest in agriculture, and less productive households, as well as issues related to land rights and land administration.

Water Resources

While the response of livestock to known increases in temperature is predictable, in terms of increased demand for water, attempts to quantify the impacts of Climate Change on water resources in the land-based livestock systems in developing countries are fraught with uncertainties.

This is more so particularly in situations where groundwater accounts for a substantial portion of the supply of water to livestock, which is the case in many grazing systems.

The coming decades will see increasing demand and competition for water in many places, and policies that can address allocation and efficiency issues will increasingly be needed.

There is also need to empower livestock farmers on various ways of sustainable livestock farming, combating the impact of Climate Change on livestock production thus increasing the possibility of meeting the livestock and livestock products demand.

ACCCKF: Feedback:

 Tatenda Dezah is a Zimbabwe based animal nutritionist. He can be contacted on