Metabolic Advantages of Feeding Bulls Moringa Leaves, Twigs, and Branches as a Primary Concentrate Ingredient – texasagpress

Introduction

The environmental impact of beef cattle production is a pressing concern, particularly in tropical developing countries where low-quality crop residues and byproducts are commonly used as feed. The anaerobic fermentation of these feedstuffs in the rumen of Zebu beef cattle results in significant dietary nutrient loss, primarily in the form of methane (CH₄) emissions. Research indicates that this loss can range from 4.8% to 13.7% of dietary gross energy (GE) (Kaewpila and Sommart, 2016). Additionally, the management of manure, which undergoes microbial decomposition, can lead to the emission of nitrous oxide (N₂O) through nitrification and denitrification processes. The livestock sector contributes approximately 18% of anthropogenic greenhouse gas emissions annually, exacerbating global warming (Gerber et al., 2013). In Bangladesh alone, livestock greenhouse gas emissions are estimated at around 70,000 Gg/year of carbon dioxide equivalent (Das et al., 2020).

Mitigating these emissions requires improving dietary efficiency in cattle. Enhancing nutrient utilization, particularly of energy and protein, can minimize unproductive waste and subsequent greenhouse gas emissions. Studies have shown that diets with more digestible ingredients can reduce the conversion of dietary GE to CH₄ (Kurihara et al., 1999; Liu et al., 2017). Dietary strategies have been effective in reducing enteric CH₄ emissions in ruminants, with some reports indicating reductions of up to 40% through dietary manipulation (Benchaar et al., 2001). Furthermore, improving feed quality can lead to less manure nitrogen, thereby reducing emissions of CH₄, N₂O, and ammonia (NH₃).

One promising approach to reducing dietary energy loss as CH₄ involves supplementing cattle diets with fats, organic acids, plant secondary metabolites, essential oils, and probiotics (Johnson and Johnson, 1995; Castillo et al., 2004; Beauchemin et al., 2008; Tamminga et al., 2007; Su and Chen, 2020). Among these, Moringa oleifera has emerged as a particularly effective supplement due to its rich content of secondary metabolites that can enhance nutrient metabolism and reduce rumen CH₄ production (Premi and Sharma, 2017; Su and Chen, 2020). Studies have shown that incorporating moringa into dairy cattle diets can alter the composition and diversity of fecal methanogens, leading to reduced enteric CH₄ emissions (Dong et al., 2019).

In addition to its potential for reducing greenhouse gas emissions, moringa has been associated with improved nutrient digestibility and animal performance. Replacing conventional feed ingredients with moringa has shown promising results in enhancing the quality of meat and milk (Qwele et al., 2013). Moreover, the bioactive compounds in moringa may promote reproductive health in livestock, as evidenced by increased litter size and improved semen quality in bulls (Zeng et al., 2019; Syarifuddin et al., 2017).

This study aims to investigate the efficiency of dietary nutrient utilization and the impact of moringa leaves, twigs, and branches on the semen quality of bulls when used as a major ingredient in their concentrate diet.

Materials and Methods

Study Location and Ethical Statement

The study was conducted at the Cattle Research Farm of the Bangladesh Livestock Research Institute (BLRI) in Savar, Dhaka, Bangladesh. The trial took place from September to November 2019, during which the average air temperature was 28(±3)°C with a humidity of 73(±6)%. The care and management of the experimental bulls adhered to the guidelines established by Curtis and Nimz (1988) and were approved by the Annual Research Evaluation Committee of BLRI (2019).

Production of Moringa Mash

Moringa mash was produced by collecting leaves, twigs, and branches (2–3 cm) from a designated plot at the BLRI Cattle Research Farm. The biomass was mechanically chopped, sun-dried for 24–32 hours, and ground into a fine powder using an electric grinder. The resulting moringa mash was stored in plastic drums until it was used to formulate different concentrate mixtures.

Ensiling of Maize

Maize (Zea mays) was harvested at 85 days of cultivation, chopped into 2–3 cm pieces, and ensiled in a pit without any additives. The silage was provided to the trial bulls as a basal feedstuff during the feeding trial.

Selection and Management of Bulls

Twenty-one bulls aged 25–32 months were selected from a large Red Chittagong Cattle (RCC) herd at BLRI. The bulls were individually housed in concrete stalls with continuous access to clean drinking water. They were initially fed maize silage supplemented with a conventional concentrate mixture for a 15-day adjustment period. After this period, the bulls were divided into three groups based on live weight and fed experimental diets for 65 days.

Feeding Management of Bulls

The bulls were weighed biweekly before morning feeding to adjust their daily concentrate mixture allowances. The control group received a conventional concentrate mixture, while the other groups received concentrate mixtures containing either 25% or 50% moringa mash. All concentrate mixtures were iso-nitrogenous and produced weekly.

Metabolism Trial

On the 51st day of the feeding trial, four bulls from each group were transferred to metabolic crates to study nutrient digestibility and metabolism. Feces and urine samples were collected and analyzed for energy content and nitrogen balance.

Chemical Analysis of Samples

The dry matter (DM), ash, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of the feed samples were determined using standard methods (AOAC, 2006; Van Soest et al., 1991). The GE content of feeds and feces was measured using a bomb calorimeter.

Calculations

The GE intake, digestible energy (DE) intake, and urinary energy (UE) excretion were calculated based on the collected data. The methane emission factor was also calculated using established equations.

Semen Quality of Bulls

After the feeding trial, semen was collected from bulls to evaluate volume and quality. The semen was analyzed using Computer Assisted Semen Analyzer (CASA) technology.

Statistical Analysis

Data were analyzed using IBM SPSS statistical software, with significant differences determined using Duncan’s multiple range test.

Results

Nutrient Intake and Live Weight Changes in Bulls

The dietary DM intake of bulls remained consistent across all groups, with no significant differences observed. The intake of organic matter, crude protein, and fiber components was also similar among groups. However, the intake of ADF and GE decreased with increasing levels of moringa mash.

Digestibility of Nutrients

The addition of moringa did not significantly affect the digestibility of DM and nutrients. However, there was a tendency for greater DE with increased moringa levels in the diet.

Metabolism of Nutrients

The metabolism trial indicated that the addition of moringa did not significantly impact energy and nitrogen metabolism. Nevertheless, a trend toward increased nitrogen balance was observed with higher levels of moringa in the diet.

Semen Quality of Bulls

The inclusion of moringa in the diets significantly improved the progressive motility of bull sperm, while also tending to reduce the incidence of abnormal sperm.

Discussion

The findings of this study suggest that incorporating moringa into the diets of bulls can enhance nutrient utilization without negatively impacting intake or weight gain. The improved semen quality associated with moringa supplementation highlights its potential benefits for reproductive performance in bulls.

The reduction in methane emissions and urinary nitrogen loss with increased moringa levels indicates that this dietary strategy could contribute to more sustainable beef production practices. The results align with previous studies that have demonstrated the positive effects of moringa on animal performance and environmental impact.

Conclusion

In conclusion, replacing conventional concentrate ingredients with moringa mash in beef cattle diets can enhance nutrient utilization and reduce greenhouse gas emissions. The study demonstrates that incorporating moringa at levels of up to 50% in concentrate mixtures can maintain live weight gain while improving reproductive performance. This dietary strategy not only benefits animal health but also contributes to reducing the environmental footprint of beef production.

Data Availability Statement

The original contributions presented in this study are included in the article, and further inquiries can be directed to the corresponding authors.

Ethics Statement

The animal study was reviewed and approved by the Annual Research Evaluation Committee of Bangladesh Livestock Research Institute, 2019.

Author Contributions

ND and NS conceived and designed the study, conducted trial and laboratory work, interpreted the data, and drafted the manuscript. MK and GD were involved in semen evaluation, data analysis, and manuscript drafting. MI prepared and analyzed feeding trial samples.

Funding

This work was funded by the Bangladesh Livestock Research Institute, Dhaka 1341, Bangladesh.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s Note

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References

The references cited in this article provide a comprehensive background on the topics discussed, including the effects of dietary strategies on methane emissions, nutrient utilization, and the benefits of moringa in livestock diets.