The zebu breeds analyzed were all pure in origin (PO), that is, genealogical registered by the Brazilian Association of Zebus Breeders (ABCZ). This study was limited to the Zebu breeds in this herd book breeds as other breeds have been studied elsewhere and by other research groups (for example Costa et al. 2014 for Holstein-Friesian; Costa et al. 2020 for Girolando; Souza et al. 2022 for Locally Adapted breeds in Brazil). The highest concentration of zebu breeds occurred in the Midwest, followed by the Southeast and North, explained by their well known livestock farming aptitude. This was evident with the position of the midpoint of these breeds, being almost all located in the central region of the country, as seen by Teixeira and Hespanhol (2014) and McManus et al. (2016), who observed the same location as the midpoint for all cattle production in Brazil. These last authors, looking at the dynamics of cattle production in Brazil show a tendency towards north western regions which has implications not only for environmental factors, such as pasture type, temperature and humidity but also for the need of political and infrastructure changes, aiming to fostering the livestock sector.
The lower occurrence of zebu cattle breeds in the South region was due to the traditional use of European breeds, as verified by Braga et al. (2015). Regardless of the type of use, the proportion of herds with European breeds increases the further one moves towards the southern states of the country.
In the states of the Northeast, a region known as the drought polygon, a smaller occurrence of zebu cattle herds was observed due to their highly susceptiblity to long periods of high temperatures and absence of precipitation (Lôbo et al. 2011), which directly affects the selection of local livestock, favoring the occurence of other species such as sheep and goats (Hermuche et al. 2013; McManus et al. 2014a). However, a higher occurrence of the Sindhi breeds was observed for this region, indicating a more local occupation (Panetto et al. 2017; Melo et al. 2020). This is because Sindhi animals have shown great rusticity and tolerance to thermal stress, maintaining high productive and reproductive efficiency in the adverse environments (Souza et al. 2007; Furtado et al. 2012; Saraiva et al. 2015; Oliveira et al. 2017).
Geographic distribution maps showed an expected trend, where the Nellore breed is widely distributed throughout the country (Fig. 2), possibly due to its adaptation to different environments (Bianchini et al. 2006). The Indubrasil breed, developed by crossbreeding in Brazil, was highly used in the middle of the last century (Santiago 1975), but interest has decreased in its use (Carneiro et al. 2009). Calculating the midpoint also helps us understand breed distribution and eventual need for conservation measures (McManus et al. 2014b). For example, breeds with low distribution from the midpoint are more vulnerable to climatic or health disasters.
The national distribution of the zebu cattle breeds when analyzed by type of production, beef, dairy and dual-purpose showed that the majority of herds (80%) are less than 1,000 km from the midpoint of the breeds. This proximity between the herds can lead to problems, such as breed loss during possible health epidemics and increased inbreeding due to a possible lack of effective numbers of animals. Therefore increased crossbreeding may arise reducing purebred numbers. According to McManus et al. (2014b), diseases, especially infectious, can be catastrophic for a very localized breed. Also, Mudadu et al. (2016), observed a high degree of kinship in genomic samples from Nellore animals that were reared close to each other. Special attention should be paid to the Polled Sindhi and Polled Indubrasil breeds, which, due to the shorter distance (midpoint <500 Km), may suffer greater impacts when compared to the other better distributed breeds.
Climate is important for raising cattle in Brazil, especially for beef cattle, as 82% of the herd was reared at pasture (Quintiliano and Paranhos da Costa 2008). Precipitation was the only climatic variable influencing the occurrence of Nelore, Polled Nelore, Brahman and Tabapuã beef breeds. These breeds have a wide distribution throughout the country, probably due to the similarities in physical characteristics (skin and coat pigmentation) and adaptation to climatic effects (usually with dark skin and light coat), as verified by Shiota et al. (2013) and Barbosa et al. (2014a,b) who likewise indicated adaptation of beef cattle animals to the climatic effects.
Complementary results were verified when the breeds were analyzed by type (beef, dairy and dual-purpose). Beef breeds usually occurred in areas with greater precipitation, NDVI, temperature, THI and relative humidity, that is, in more humid and hot regions, corroborating with McManus et al. (2016).
Areas with pastures in good conditions and the human development index influenced the occurrence of Nelore, Polled Brahman and Sindhi breeds. Polled Brahman and Sindhi breeds tend to be used on farms with access to production technologies, but surrounded by different regions regarding socio-economic development, Brahman being in regions with the highest HDI and Sindhi with the lowest. High HDI reflects in better human development conditions, usually attributed to richer regions, which in turn can lead to access to better forms of livestock breeding, due to access to better education conditions, per capita income, and life expectancy by cattle farmers, creating a favorable situation. Studies show that intellectual capital can improve innovation capabilities (Xiaobo and Sivalogathasan 2013) and increase added value to livestock products (Soesilowati et al. 2017) while Peñalba and Elazegui (2013) also showed that the ability of a farmer to adapt to change was affected by HDI. Costa et al. (2013) found that most farmers in a state in southern Brazil only had primary school education, and that most of these farmers did not keep records and carried out inadequate management practices.
The beef zebu cattle breeds occurred in both cultivated pasture areas with good (CPGC) and degraded (DCP) conditions, possibly due to these breeds are spread over a large part of the Brazilian territory, being reared in various environments and consequently in different pasture quality situations. There are approximately 190Mha of pasture sustaining 209 million cattle in Brazil (Jank et al. 2013). Of this about 74Mha are native species, 99Mha Brachiaria spp and 17Mha of other cultivars (ANUALPEC 2008). 8Mha is renovated each year and about 4MHa are occupied by integrated crop-livestock systems. This means that a significant number of cattle are reared on suboptimal pastures as seen by Costa et al. (2013) with dairy cows in southern Brazil. Oliveira et al. (2015) also showed that implementation of hygiene regulations on farms was limited by lack of understanding of the importance of these measures by cattle farmer, as well as lack of adequate infrastructure such as electrification and roads. Distribution studies such as the present one can thereby help to identify where increased public policies (fiscal incentive, access to finance, among others), infrastructure, and specify training are necessary to improve the production.
However, beef type also occurred in areas of rivers and streams with forest protection (RSFP), and establishments without family farming (NEFA), probably due to the high number of animals of this type in data worked, favored by the aptitude of the market, as seen also by McManus et al. (2014b) in a study with sheep breeds distribuiction in Brazil. Also, these beef breeds had a high distribution in the Brazilian territory influenced by the commercialization made by the Breeders' Associations of Brazil, which may also have favored beef Zebu breeds.
In areas with cultivated cutting forages (CCF), areas with rotational grazing system (RGS), and areas with integrated crop-livestock forest systems (ICLFS), there was a higher occurrence of dual-purpose and dairy breeds, characteristics of more fertile soils. This was also seen by McManus et al. (2014a) and McManus et al. (2016) who observed an increase in breeds with dairy aptitude in more productive regions. In addition, dairy production can be more favored in areas with greater elevation in relation to sea level, maybe due to better climatic conditions. Forest protection for rivers and streams was important for climate regulation, heat absorption and humidity regulation (Silvano et al. 2005). Nevertheless, in recent years, there has been a reduction in this protection (Taniwaki et al. 2017), especially due to corn plantations for silage, sugarcane plantations, citrus, silviculture, urbanization, and pasture creation which have been shown to be linked to dairy cattle production (Costa et al. 2014). Most farms do not have shade protection or adequate water supply for cattle (Costa et al. 2013), which directly affects performance.
A trend towards dairy breed occurrence was observed in establishments with family agriculture (EFA), showing a historical tendency, where small to medium-sized properties managed by families usually explore dairy breeds. This was also seen by Guilhoto et al. (2006) and Wilkinson (2013), as well as agricultural research data (IBGE 2012), where more than 80% of the farms fall into this category.
The present study looked at breed occurance relative to environmental and socio-economic factors. As one factor changes, so may others and the relationships between them (Costa et al. 2013). Barcellos et al. (2011) suggested intensification as the means for the cattle industry to reduce pressure on forest margins and free-up land for soybean or sugarcane production. Sparovek et al. (2009) showed that this expansion resulted in a significant reduction of pastures and number of cattle and higher economic growth compared to neighboring areas. Maranhão et al. (2019) showed soybean production replacing beef cattle production in the savanna region of Brazil. The latter migrated to the Amazon region which may explain some of the results seen here, with beef cattle seen in regions with higher temperatures and lower rainfall. Nevertheless, there are large regions of overlap with these productions as well as other crops due to the need for alternative sources of feeding, especially for dairy and dual-purpose cattle.
 “Family Agriculture” is considered as defined in the Item II of Article 4 of the Land Act, Law No. 4504 of November 30, 2004: “a farm that is directly and personally operated by the farmer and his family, to absorb their entire workforce, providing them with subsistence as well as social and economic progress, with a maximum area fixed by region and type of operation, and occasionally worked with the help of others.”