Effects of harvest height and time on hay yield and quality of some sweet sorghum and sorghum Sudangrass hybrid varieties

Background

This experiment was conducted in the Research and Application Field of Canakkale Onsekiz Mart University, Faculty of Agriculture, during the 2020 and 2021 summer period. The objective of this experiment was to determine the effects of different harvesting heights on forage yields and crude ash, fat, protein, and carbon and nitrogen content of leaves and stalks of sweet sorghum (SS) and sorghum sudangrass hybrid (SSH) cultivars.

Methods

Nutri Honey and Nutrima varieties of SSH and the M81-E and Topper-76 varieties of SS were used in this study. The experiment was conducted using the randomized complete block design with four replications. The main plots each included two early and late varieties of SS and SSH cultivars, while the subplots were used to test different harvesting heights (30, 60, 90, 120, 150 cm) and physiological parameters of each crop.

Results

The results of this study showed that dry forage yields increased with plant growth, with the amount of forage produced at the end of the growth cycle increasing 172.2% compared to the early growth stages. Carbon (C) content of leaves decreased by 6.5%, nitrogen (N) by 46%, crude protein (CP) by 54%, crude fat (CF) by 34%, while crude ash (CA) content increased by 6% due to the increase in plant height harvest. At the same time, in parallel with the increase in plant height at harvest, the nitrogen content of the stems of the plants decreased by 87%, crude protein by 65%, crude ash by 33% and crude fat by 41%, while the carbon content increased by 4%. As plant height at harvest increased, hay yield increased but nutrient contents of the hay decreased. However, the Nutrima, Nutri Honey and M81-E sorghum cultivars, harvested three times at heights of 90 to 120 cm, are recommended for the highest yield.

Feeding intact proteins, peptides, or free amino acids to monogastric farm animals

For terrestrial farm animals, intact protein sources like soybean meal have been the main ingredients providing the required amino acids (AA) to sustain life. However, in recent years, the availability of hydrolysed protein sources and free AA has led to the use of other forms of AA to feed farm animals. The advent of using these new forms is especially important to reduce the negative environmental impacts of animal production because these new forms allow reducing the dietary crude protein content and provide more digestible materials. However, the form in which dietary AA are provided can have an effect on the dynamics of nutrient availability for protein deposition and tissue growth including the efficiency of nutrient utilization. In this literature review, the use of different forms of AA in animal diets is explored, and their differences in digestion and absorption rates are focused on. These differences affect the postprandial plasma appearance of AA, which can have metabolic consequences, like greater insulin response when free AA or hydrolysates instead of intact proteins are fed, which can have a profound effect on metabolism and growth performance. Nevertheless, the use and application of the different AA forms in animal diets are important to achieve a more sustainable and efficient animal production system in the future, as they allow for a more precise diet formulation and reduced negative environmental impact. It is, therefore, important to differentiate the physiological and metabolic effects of different forms of AA to maximize their nutritional value in animal diets.

Earthworm as an alternative protein source in poultry and fish farming: Current applications and future perspectives

Among the different agricultural activities, the livestock is one of the most impacting on the environment. The feeding of animals is often the main responsible of the adverse environmental impact related to animal productions. Above all for intensive production, the consumption of protein feed is a key aspect for the achievement of sustainable production processes. The actual consumption of soybean meal and fish meal is not sustainable due to the related environmental impact and to the increasing prices. Among the different alternative protein sources, in the last 20 years, the attention of research centres and private companies focused on insects, algae and other invertebrates but, up to now, little consideration was paid to the use of fresh earthworm or earthworm meal as a protein feed for monogastric animals. The use of earthworms as an alternative protein source for fish and poultry feeding is an opportunity for providing environmental services via cleaner technologies. Thanks to earthworms, organic wastes and by-products generated by livestock activities can be valorised and become a resource for animal feeding in a circular perspective. In this context, this manuscript was designed to summarize the productivity, suitability and effectiveness issues connected with the utilization of earthworms as alternative protein feed in poultry production as well as in aquaculture. The studies investigating the earthworm meal use are quite old above all those carried out in Europe; however, some general indications can be drawn: both for broiler and fish, the parameters usually evaluated are body weight gain, growth rate, feed intake and feed conversion rate, the acceptability level of earthworm meal in broiler diet is lower than 15% while in trout diet ranges between 25 and 30%. The inclusion of earthworm meal in diets with an inclusion level lower than the acceptability threshold allows good productive performances without affecting the quality of the final food products.

Feeding dicyandiamide (DCD) to cattle: An effective method to reduce N2O emissions from urine patches in a heavy-textured soil under temperate climatic conditions

Nitrate (NO₃^-) leaching and nitrous oxide (N₂O) emission from urine patches in grazed pastures are key sources of water and air pollution, respectively. Broadcast spraying of the nitrification inhibitor dicyandiamide (DCD) has been shown to reduce these losses, but it is expensive. As an alternative, it had been demonstrated that feeding DCD to cattle (after manual mixing with supplementary feeds) was a practical, effective and cheaper method to deliver high DCD rates within urine patches. This two-year study carried out on simulated urine patches in three application seasons (spring, summer, autumn) explored the efficacy of DCD feeding to cattle to reduce N losses from grazed pasture soil in a heavy-textured soil under temperate climatic conditions. In each application season, DCD fed to cows, then excreted with urine and applied at a rate of 30kgDCDha^-1 (treatment U+DCD³⁰-f) was as effective as powdered DCD mixed with normal urine and applied at the same rate (treatment U+DCD³⁰) at reducing cumulative N₂O-N emissions and the N₂O-N emission factor (EF3, expressed as % of N applied). Increasing DCD loading within urine patches from 10 to 30kgDCDha^-1 improved efficacy by significantly reducing the EF3 from 34% to 64%, which highlights that under local conditions, 10kgDCDha^-1 (the recommended rate for commercial use in New Zealand) was not the optimum DCD rate to curb N₂O emissions. The modelling of EF3 in this study also suggests that N mitigation should be given more attention when soil moisture is going to be high, which can be predicted with short-term weather forecasting. DCD feeding, for instance in autumn when cows are not lactating and the risk of N losses is high, could then be reduced by focusing mainly on those forecasted wet periods.

Do whole-food animal feeding studies have any value in the safety assessment of GM crops?

The use of whole-food (grain meal contained in feed) animal-feeding studies to support the safety assessment of genetically modified crops has been contentious. This may be, in part, a consequence of poorly agreed upon study objectives. Whole-food animal-feeding studies have been postulated to be useful in detecting both expected and unexpected effects on the composition of genetically modified crops. While the justification of animal feeding studies to detect unexpected effects may be inadequately supported, there may be better justification to conduct such studies in specific cases to investigate the consequences of expected compositional effects including expression of transgenic proteins. Such studies may be justified when (1) safety cannot reasonably be predicted from other evidence, (2) reasonable hypothesis for adverse effects are postulated, (3) the compositional component in question cannot be isolated or enriched in an active form for inclusion in animal feeding studies, and (4) reasonable multiples of exposure can be accomplished relative to human diets. The study design for whole-food animal-feeding studies should be hypotheses-driven, and the types of data collected should be consistent with adverse effects that are known to occur from dietary components of biological origin.

Biomass of Spirulina maxima enriched by biosorption process as a new feed supplement for swine

This paper deals with the new mineral feed additives with Cu produced in a biosorption process from a semi-technical scale. The natural biomass of edible microalga Spirulina sp. was enriched with Cu(II) and then used as a mineral supplement in feeding experiments on swine to assess its nutrition properties. A total of 24 piglets divided into two groups (control and experimental) were used to determine the bioavailability of a new generation of mineral feed additives based on Spirulina maxima. The control group was feed using traditional inorganic supplements of microelements, while the experimental group was fed with the feed containing the biomass of S. maxima enriched with Cu by biosorption. The apparent absorption was 30 % (P < 0.05) higher in the experimental group. No effect on the production results (average daily feed intake, average daily gain, feed conversion ratio) was detected. It was found that copper concentration in feces in the experimental group was 60 % (P < 0.05) lower than in the control group. The new preparation-a dietary supplement with microelements produced by biosorption based on biomass of microalgae S. maxima-is a promising alternative to currently used inorganic salts as the source of nutritionally important microelements.