Elsevier

Livestock Science

Volume 251, September 2021, 104633
Livestock Science

Productive performance and economic viability of beef cattle subjected to different castration methods in the Western Amazon

https://doi.org/10.1016/j.livsci.2021.104633Get rights and content

Highlights

  • Immunocastrated animals have similar weight gain compared to intact animals.

  • No negative influence of immunocastration was observed on the growth rate of animals.

  • Immunocastration reduced, on average, 60% serum testosterone concentration.

  • Higher profitability in the slaughter of immunocastrated animals was obtained compared to surgically castrated animals.

  • Immunocastration is effective and allows for the deposition of desirable subcutaneous fat.

Abstract

This study aimed to assess the productive performance and economic viability of intact, surgically castrated, and immunocastrated cattle. The experiment was completely randomized with 102 animals divided into three treatments: intact (control group), surgically castrated (group I), and immunocastrated (group II). Animal production indices, circulating testosterone levels, carcass yield and finishing, and profit generated by each method after slaughter were determined. Control group and immunocastrated animals showed a higher (p<0.05) total weight gain (TWG) than surgically castrated animals, with means of 181.85, 170.34, and 148.88 kg, respectively. Average daily weight gain (ADG) in immunocastrated was higher (p<0.05) than that obtained by surgically castrated, not differing (p<0.05) from intact animals, with means of 0.534, 0.466, and 0.570 kg/animal, respectively. The assessment of the degree of finishing showed that surgically castrated animals had an adequate fat deposition (three to six millimeters) and maturity. On the other hand, immunocastrated animals presented 50.0% of carcasses with tolerable classification, 36.11% desirable, and 13.89% undesirable. Control animals had a higher testosterone concentration than the other groups (p<0.05), with a mean of 128.56 ng/dL. Immunocastrated animals had a 60.91% reduction in testosterone concentration compared to control animals. However, these were significantly higher (p<0.05) than surgically castrated animals, which had a mean concentration of 12.34 ng/dL, representing a reduction of 90.4% in comparison with control animals. Therefore, immunocastration reduced the damages caused by surgical castration and qualitatively improved the carcass of Nellore animals, thus joining animal welfare and production. However, intact animals showed higher profitability.

Introduction

The Brazilian cattle herd accounts for approximately 213 million head of animals, with a distribution of over 162.53 million hectares of pasture, with 19% of this area being arable (BBEF, 2020). As a result, Brazil is considered worldwide as one of the greatest powers in the segment of beef production and commercialization (BBEF, 2020). Furthermore, cattle farming in the Legal Amazon region, a term instituted by the Brazilian government (Law 1,806 of January 6, 1953) to represent an area that corresponds to 58.9% of the territory, has been relevant to a national level, as the activity is present in the countless agricultural establishments of the region (Santos et al., 2017).

The heterogeneity in the Brazilian livestock systems is the main attribute that favors the dissemination of cattle activity since there are very different profiles of production systems. This agglomerated complex can be divided into two distinct groups. On the one hand, groups that adopt technologies and are efficient in management and commercialization, and, on the other hand, groups that are less technified, with precarious management of the enterprise (Carvalho and Zen, 2017). Thus, the concern with the environmental issue, reduction of expenses with food, and higher profitability, especially in the most precarious systems, has motivated the search for sustainable management technologies that allow an increase in productivity and optimization of productive systems in cattle farming (Gléria et al., 2017).

In addition, the performance of more demanding and conscientious consumers relative to health problems related to eating fatty meats has led to a predilection for better-finished carcasses, with low-fat levels, not compromising the cooling and quality of meat in refrigerators (Moletta et al., 2014).

In this sense, there is a preference of slaughterhouses for animals with more uniform carcasses, with an adequate degree of finishing and, consequently, better quality, thus preserving the burning of meat during cooling. In tropical pastures, these carcasses, usually with low use of adequate nutritional programs, are easily found in castrated animals due to the interruption of the effect of testosterone in the bloodstream (Restle et al., 1994).

On the other hand, intact cattle subjected to inappropriate nutritional management results in the discount of their carcasses, as they have no adequate fat finishing (three to six millimeters) (BRASIL, 1989) at the same time interval of castrated animals (Vaz et al., 2013).

In general, intact animals have carcasses with a better conformation and a higher proportion of muscles, and better feed conversion and meat production than castrated animals (Vaz et al., 2013, Restle et al., 2000). However, aggressiveness and higher libido are among the problems faced when opting for raising intact males to produce meat (Andreo et al., 2013, Domingues et al., 2019).

In this context, new alternatives, such as immunocastration, have emerged to preserve the qualities of intact males and meet the requirements for more uniform carcasses in the consumer market. This technique is based on the use of a vaccine that induces the formation of antibodies against the gonadotropin-releasing factor (GnRH), reducing the production of testicular steroids (Zamaratskaia et al., 2007, Zanella et al., 2009).

Therefore, this study aimed to assess the zootechnical performance and economic viability of Nellore (Bos taurus indicus) steers submitted or not to traditional castration and immunocastration under environmental conditions of the Western Amazon to prove the real effectiveness of this method relative to the use or not of surgical castration.

Section snippets

Bioethics

The research was approved by the Ethics Committee on Animal Research (CEUA) of the Federal University of Acre (UFAC) under the No. 10/2017, following the guidelines of the National Council for the Control of Animal Experimentation (CONCEA, Law 11794 of October 8, 2008) and other subsequent normative resolutions.

Location

The experiment was carried out on a private property located in the municipality of Senador Guiomard, state of Acre, in the North of Brazil. The regional climate is tropical, with a

Results

A mean total dry matter availability of 6,918 kg/ha (±1,721.4 SD) was observed during the study, with a mean height of 25.6 cm.

Regarding the nutritional parameters of the forage (Table 2), the mean CP contents were higher than the minimum values recommended in the literature.

Furthermore, higher performance was observed in the group of intact animals in the period corresponding to the ADG1 analysis. Moreover, the effects of vaccine application in the stage referring to ADG2 were not observed in

Discussion

In general, the total dry matter availability (TDMA) is a limiting factor in assessments of productive performance, especially in tropical regions, because it interferes with animal production depending on the situation by acting directly on the dry matter intake levels (Santos et al., 2004). However, the TDMA values of the present study were above the critical value of 2,000 kg/ha, and availability lower than this value leads the animal to not reach its maximum intake, and production becomes

Conflict of interest

The authors declare that there is no conflict of interest.

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