The profitability of dairy farming primarily depends on the productivity of the cow herd, which, in turn, depends on conditions of nutrition. Productivity of cattle in Lithuanian farms has been growing through recent years and the average milk productivity from one cow was 4484 kg, and in specialized farms and corporations–5632 kg of milk. The positive impact was the result of genetic characteristics, improved nutrition and keeping conditions of the cattle, and the experience of dairy farmers. While productivity is growing, the nutritional needs also change depending on the animal’s age, physiological state, and lactation period.

In addition, most nutritional substances in the ration have to be in the proper proportion; as a result, balancing rations for cows of high productivity is not an easy task. The rations made of local production forage and grains often lack energy and nutritional components, causing the cow to compensate from its body reserves, resulting in decreased milk productivity and physical condition. Proper body condition of cows in all lactation stages increases milk yield. The physical condition affects the number of stored energy reserves and differing reserves in different lactation periods. 

To evaluate a dairy cow’s body condition, it is important to know its stage of productivity and to estimate the condition standard limits for the particular period. It has been established that the stage of body condition at the calving period is a crucial index, for predicting milk productivity during the next lactation. Cows scoring less than 3.0 at calving produce less milk; others concur that milk productivity is smaller than attenuated cows. 

To achieve higher milk productivity, changes in body condition should be controlled. If the body condition at calving matches the standards, and in the first weeks after calving the rations are properly balanced, it would be possible to avoid a decrease in milk production. Periodic evaluation and analysis of a cow’s body condition increase understanding of the changes in energy balance in the animal organism, allows pre-diagnosis of health disorders, forecasts milk productivity, and helps ascertain errors in feeding.  

Arthrospira (Spirulina) platensis is also used as an additive for other livestock. In rabbit growth, trials of diet efficiency with the inclusion of Arthrospira (Spirulina)  platensis show that the final weight, weight gain, and feed efficiency did not differ significantly among the dietary treatments, but an Arthrospira (Spirulina)  platensis inclusion level of 10% gave the highest feed intake. Various supplements, additives, pre-mixes, etc. are used for the balance/compensation of rations.  Currently, significant attention is being paid to natural and safe additives, which increase cow productivity, and do not harm animal and human health. The cyanobacterium Arthrospira (Spirulina) platensis has even been used by humans because of its nutritional and possible medicinal effects.  

Scientists from around the world have been looking for ways to use the biomass of oceans and fresh water for many years; one possibility is creating new, safe food and forage supplements and additives. For this reason, examining low organisms such as blue-green algae as a nutritional source for animals is receiving considerable attention.  

Algae are single-celled and multi-cellular organisms, mainly lower-order water plants,  growing in the seas, lakes, rivers, ponds, and swamps, and are also found on humid soil,  banks, and wet stones. To date, more than 25 000 species of algae have been counted.  Algae are significant in protecting oceans and other water sources from damaging substances and compounds. have stated that algae and other water plants produce about 80% of all organic substances as a result of photosynthesis;  earth plants produce only the remaining 20%. 

Therefore, from 1 hectare of the sea, it is possible to get about 10 tons of algae dry mass. Through the evolutionary process, algae have adapted to concentrate many chemical elements that serve as raw material, with easily absorbed elements that make them useful for food, forage, and the pharmacy industry. Some sea algae (i.e. sea cabbage), with iodine removed, are used for animal feed.  

In fresh waters, green algae and blue algae – cyanobacteria – predominate, but can also be grown in artificial, enclosed ecological systems. Green algae Chlorella Vulgaris, widely used in the pharmacy industry, is common in alkaline reaction water ponds in South America, Asia, and Africa which offer enough warmth and light. Although Arthrospira (Spirulina) platensis is one of the oldest algae,  its appearance dating back approximately 3.5 billion years, it has recently become of interest to nutritionists. Its cells’ differentiation is low but, with its unique chemical composition, can be a preferred raw material for the pharmacy, food, and feed industries. Arthrospira (Spirulina) platensis organic materials consist of proteins – 60-70%, carbohydrates – 10-20%, fat – 5%, and fiber – 2%. 

According to the literature, the dry biomass of Arthrospira (Spirulina) platensis has more protein than barley, wheat, and Chlorella Vulgaris. Compared with proteins of other raw materials, the proteins of Arthrospira (Spirulina) platensis have more valuable amino acids as well as biologically active substances such as vitamins, minerals, poly-saccharids, which are able to form compounds with metals, etc. Among biologically active compounds, isoprenoids are especially important, positively influencing the activity of various enzymes, as well as the synthesis of nucleic acids and photosynthesis. 

Antioxidant characteristics of cyanobacteria are based on contained phytohormones and enzymes. The blue pigment phycocyanin of cyanobacteria stimulates neural and immune systems. Because of their biologically active substances, unique chemical composition,  valuable proteins, correct proportion of amino acids, and amount of vitamins and minerals, the biomass of Arthrospira (Spirulina), and platensis can be successfully used in animal nutrition. 

According to data from the experiment carried out at the Lithuanian Veterinary Academy, cow’s milk productivity increased an average of  7.6 % after receiving a feed additive of Arthrospira (Spirulina) platensis. It can be grown in special photosynthetic blocks, in certain nutritional media.  The cyanobacteria Arthrospira (Spirulina) platensis is approximately 100 times larger than the green algae Chlorella Vulgaris. Accordingly, Arthrospira (Spirulina) platensis is more productive, is more easily grown, and does not need to be centrifuged like  Chlorella Vulgaris. 

Lithuanians have recently started to grow cyanobacteria Arthrospira (Spirulina)  platensis artificially for preparation in additives for animal fodder. The main raw material for producing the additive is a biomass of cyanobacteria  Arthrospira (Spirulina) platensis. Cyanobacteria are grown in bio-photoreactors and their biomass is recorded in a technological process using fructose and molasses as media. 

The final product, named ‘Spirulina platensis’, designed for combined fodder enrichment with valuable nutritive elements, is produced after inserting 5% of the biomass of cyanobacteria Arthrospira (Spirulina) platensis raw material into the residue of linseed or sunflower. Information about its use as an additive is still insufficient in  Lithuania and neighboring countries. 

The aim of the research is to estimate and evaluate the influence of fodder additive ‘Spirulina platensis’ (cyanobacteria Arthrospira (Spirulina) platensis) on the body condition of cows, fodder intake, milk productivity, and biochemical indices.