Shelter and shade for grazing sheep: implications for animal welfare and production and for landscape health

Abstract

Shade and shelter may provide protection from cold and heat stress, a source of feed during prolonged or seasonal drought, specific essential nutrients, increased pasture and crop production and improved landscape health. Cold stress contributes to the average of 8% (single) and 24% (twin) of lambs that die within 3 days of birth in Australia and the estimated 0.7% of the Australian flock that die post-shearing during extreme or unseasonal weather. Shelter has resulted in an average reduction in mortality of 17.5% for twin-born lambs and 7% for single-born lambs according to Australian studies and decreases the susceptibility of ewes to metabolic disease and possibly dystocia. Because many of the published studies are from research areas where cold stress is expected, they are not indicative of industry-wide responses, a research priority is to determine the probability of lamb and ewe deaths from cold stress across different sheep production areas. Although shelter may improve lamb survival, ewes do not always choose to lamb in a sheltered location. For this reason, there is a requirement for research into the voluntary use of shelter in commercial-sized paddocks and the role that nutritive value of shelter plays in attracting and holding ewes to shelter, and to their lambs. Heat stress may also result in lamb deaths and influences feed conversion efficiency, appetite, reproduction, wool growth and disease susceptibility. The consequences of heat stress may go unnoticed over a yearly production cycle, although there is some evidence that shade may increase weaning rates and feed intake of grazing sheep. There are ancillary benefits from shade and shelter. Trees may improve crop production through reducing wind damage and evapotranspiration and provide timber. Shrubs provide feed during the summer-autumn feed gap or drought, are useful for the management of land degradation and provide habitat for native fauna. It is clear that shade and shelter in the correct locations provide a range of benefits to livestock and the landscape; nevertheless, adoption appears low. Research that focuses on defining the benefits on a farm or landscape scale is required to support extension programs.

The societal role of meat: the Dublin Declaration with an Australian perspective

“…It also appears likely that such strategies would further enhance the benefits of beef production in maintaining biodiverse habitats. Such management options are consistent with the conclusions of others (Masters et al 2010;Thompson et al 2023) that well managed animal systems can convert large quantities of non-edible biomass to high-quality foods, while providing diversity and respecting ecological principles that offer ecosystem services.…”

“…Australian animal industries have a social and ethical obligation to deliver demonstrable animal welfare improvements as has been clearly demonstrated (Hemsworth 2018;Salvin et al 2020;Rivero and Lee 2022;Verdon 2022;Masters et al 2023). Animal welfare is a key priority for government, industry and research (Barnett and Hemsworth 2009;Hemsworth et al 2015;Colditz and Hine 2016;Kahn et al 2017;Tilbrook and Ralph 2017;Colditz 2022).…”

Herbage and sheep production from simple, diverse, and legume pastures established in an agrivoltaic production system

“…A further reason for lower lamb growth rates in spring 2022 may have been related to cooler and wetter conditions. It is likely that the energy expenditure of lambs in colder weather and frequent rainfall may have increased due to thermoregulation, at the expense of LWG (Masters et al, 2023; Tüfekci & Sejian, 2023). It is highly probable that the seed bank of annual weeds has accumulated over a long period of time, which made it challenging to establish pastures with a desirable forage composition.…”

Perspective: science and the future of livestock industries

“…One seemingly inevitable stressor is extreme weather events. Livestock managers might not be able to control the weather, but they can provide shade and shelter to reduce the impact of cold and heat ( 14 ). Moreover, genetic solutions are feasible because we are beginning to understand the genes that determine and animal’s response to a stressor and can therefore breed animals that are less reactive ( 28 ).…”

“…We now know that an increase in testis temperature reduces blood flow, thus restricting the supply of nutrients, regulatory hormones, and oxygen ( 13 ). Female reproduction is also disrupted by heat stress, as is animal welfare, such that, in Australia, shade is acknowledged by industry as the next frontier in the management of grazing animals [review: ( 14 )]. It is this no surprise that Björkbom ( 15 ) argues logically that animal welfare must be included in policies targeting food sustainability.…”