Effects of Hydroponic Fodder Feeding on Milk Yield and Composition of Dairy Cow: Review

The aim of this paper was to review the effects of hydroponic fodder feeding on milk yield and composition of the dairy cow. Hydroponic fodder is an effective solution for fodder scarcity and is very promising for sustainable livestock production in different regions of the world. Hydroponics fodder production involves growing of plants without soil for a short duration (5-10 day). In hydroponic fodder production system, it can be possible to grow 5-10kg of green fodder from 1kg seeds. The nutritional increase in crude protein, fibre, ether extract, vitamins and minerals were constantly observed in hydroponic fodder. However, there was a loss of 10-25% dry matter content depending on grain type and duration. The hydroponics fodder feeding improves milk yield and composition of a dairy cow through increased intake and digestibility of nutrients. However, more information is needed to confirm the benefit of hydroponic fodder feeding as part of ration for dairy cow. Keywords: hydroponic fodder, nutrient composition, dairy cow, milk yield, milk composition DOI : 10.7176/JNSR/9-8-01 Publication date : April 30 th 2019

2012). Hydroponic fodder is an effective solution for fodder scarcity and is very promising for sustainable livestock production in different regions. It is essentially the germination of a seed and sprouted into a high quality, highly nutritious, disease-free animal food in a hygienic environment free of chemicals like insecticides, herbicides, fungicides and artificial growth promoters (Jensen and Malter, 1995;Al-Hashmi, 2008). This process takes place in a very versatile and intensive hydroponic growing unit where only supplying cereal grain with necessary water, nutrients and sunlight to produce a grass and root combination that is very lush and high in nutrients. This green fodder is extremely high in protein and metabolizable energy, which is highly digestible by most animals (El-Morsy et al., 2013). Hydroponics is a year-round growing system that produces a consistent quantity and quality of plant material or fodder, regardless of outside weather.
In hydroponics fodder production technology, water-soaked seeds are kept on trays and allowed to germinate (sprout) inside controlled environment for a short duration (Taparauskiene, 2015). Green fodder production takes 5 to 10 days (Cuddeford, 1989;Mooney, 2005;Merisco, 2009) with a 0.5m 3 usage of water for production of 1 tons of feed in the area of about 100m 2 (Taparauskiene, 2015). From 1kg seeds, it can be possible to grow 5-10kg of green fodder (Buston et al., 2002;Shtaya, 2004;Al-Karaki, 2011;Islam et al., 2016). In addition to this, recycling of water in hydroponic fodder production system allows solving problems related to water scarcity. At the end of the growing period, the fodder is fed to livestock as a supplement in the same way that hay and silage are currently used (Merisco, 2009).

Nutritive Value of Hydroponic Fodder
The chemical composition of hydroponic fodder grown from various grains was reported by different research in various conditions. There is a general consensus that there is no significant gain in fodder dry matter increase through sprouting grain and producing hydroponic fodder when compared to the starting dry matter of the grain used. Grain usually contains around 85-87% dry matter and hydroponic fodder usually contains 80-85% water (Weldegerima, 2015). Research results show a large diversity in dry matter gain or loss, ranging from 10% loss to 15% gain over 8-10 sprouting cycle (Starova, 2016). Abd Rahim et al. (2015) stated that the germination of barley resulted in about 18% loss in DM. Similarly, Shtaya (2004) showed that the germination of wheat for 5 to 7 days resulted in a 17% loss of total DM while a 25% loss in DM of wheat after 12 days of sprouting. Loss of DM is probably due to the use of carbohydrates and energy by seeds for metabolic activities of the growing plant, without adequate replacement by photosynthesis of the young plant. This photosynthesis begins around the fifth day when the chloroplasts are activated (Al-Karaki and Al-Momani, 2011;Adjlane et al., 2016). In Dung et al. (2005) study, there was a 21.9% loss of DM over 7 day sprouting period. Seed soaking leads to the activation of enzymes, solubilisation and digestion of starch stored in the endosperm to simple sugars. This provides a substrate for the young developing plant for metabolic activities. These substrates are respired to produce energy, giving off carbon dioxide and water. This loss of carbon dioxide leads to a loss in dry matter (Emam, 2016 2007Thadchanamoorthy et al. (2012 studied hydroponic maize fodder as a source of feed for six New Zealand White rabbits (4 to 5 weeks old). At 10 th day after planting moisture, ash, CP, EE, CF, NDF and ADF% in sprouted maize were higher (73.93, 3.09, 16.54, 6.42, 8.21, 29.27 and 10.16 % respectively) than the levels found in grain (10.26, 1.48, 8.21, 4.69, 2.11, 19.22 and 5.5% respectively). Lorenz (1980) stated that the sprouting of grain caused increased enzyme activity, a loss of total DM, an increase in total protein, a change in amino acid composition, a decrease in starch, increases in sugars, a slight increase in crude fat and crude fiber, and slightly higher amounts of certain vitamins and minerals. Most of the increases in nutrients are not true increases; they simply reflect the loss of DM, mainly in the form of carbohydrates, due to respiration during sprouting. As total carbohydrates decreases, the percentages of other nutrients are increases (Dung et al., 2005;Helal, 2015). In Al-saadi (2016) study, the crude protein, ash, ether extract, non-protein nitrogen, true protein and neutral detergent fiber were significantly higher in green fodder comparative to grain. According to Resh (2001), sprouting of grains affected the enzyme activity, increased total protein and changes in amino acid profile, increased sugars, crude fiber, certain vitamins and minerals, but decreased starch and loss of total dry matter. The enzymes also cause the inter-conversions of these simple components leading to an increase in quality of amino acids as well as the increase in concentrations of vitamins (Plaza et al., 2003). Effect on Intake Determination of dry matter intake is very important in feed evaluation, not only to prevent the deficiency or excess intake of nutrients but also can assist the use of nutrient efficiently (NRC, 2001). There are some arguments about the use of the sprouting grains for the convenience of green forage production in hydroponics system to be as part of feed in livestock feeding systems (Shtaya, 2004;Prasad, et al., 1998;Tudor et al., 2003). Sole feeding of green fodder did not support the expected production traits in the animals whereas feeding in conjunction with dry fodder improved its utilization (Prasad et al., 1998). Abd Rahim et al. (2015) noted that the dry matter intake of green fodder by feedlot cattle and dairy cattle were low due to its high moisture content. The total consumption of both as fed and dry matter was higher in dairy cows receiving 7% maize hydroponic fodder as supplementation compared with control treatment (Nugroho et al., 2015). This could be caused by a good palatability of maize hydroponic fodder, so it could stimulate the increased consumption of other types of feed Chaudry, 2007). However, there was a report which indicates a decrease in the DM intake of the animals when hydroponics fodder is fed (Heins and Paulson, 2016). Similarly, Naik et al. (2014) were reported lower dry mater intake on supplementation of hydroponic fodder for dairy cow. Lower DM intake associated with the feeding of hydroponics green fodder may be due to the high water content of the hydroponics green fodder that might have made it bulky leading to limited DM intake by the animals (Fazaeli et al. 2011). Effect on Digestibility Nutrient digestibility increased by using sprouted grains in the ruminant diet. Fayed (2011) determined that the addition of sprouted barley with rice straw and Tamarix Mannifera increased DM, OM, CP, EE, CF, NDF and ADF digestibility. This may be due to the presence of bioactive catalysts which increases digestion and absorption of nutrients and the release of energy. Similarly, Ibrahim et al. (2001) reported that addition of sprouted grains increases nutrient digestibility. Sharif et al. (2013) observed increased digestibility by using sprouted grain in the diet of broilers and large animals. This was achieved possibly by changes in rate and extent of digestion and absorption. During germination, enzymes are produced which reduces the viscosity of the digesta and improves the digestion and absorption of nutrients (Annison, 1993). This is also due to the presence of grass juice factor (Finney, 1982;Elvehjen et al., 1934) which may be a good source of nutrients for rumen micro-organisms.  Moghaddam et al. (2009) conducted an experiment to determine the effect of sprouted grains on nutrient digestibility. They replaced barley with sprouted barley at the level of 0, 33, 66 and 100%. They concluded that nutrient digestibility was increased by increasing the level of sprouted barley. They reported that 100% replacement resulted in better nutrient digestibility as compared to other levels. Similarly, Helal (2015) reported that digestibility coefficients of all nutrients were significantly higher in sprouted barley supplemented sheep. In general, feeding of hydroponics fodder increased the digestibility of the nutrients of the ration which could be attributed to the tenderness of the fodder (Reddy et al., 1988). In the Naik et al. (2014) study, there was increased (P<0.05) in the digestibility of CP and CF of the cows due to a feeding of hydroponics maize fodder. However, the increase (P>0.05) in the digestibility of DM, OM, EE and NFE was non-significant. These result revealed that feeding hydroponic fodder improves the digestibility of most nutrients.

Effects on Milk Yield and composition
Hydroponic fodder can help to improve the quality and quantity of milk production. Research results indicated that milk yield was improved. There were 3.9% increase in the milk yield due to feeding of hydroponics barley fodder (Heins and Paulson, 2016) and 13.7% increase in the milk yield due to feeding of hydroponics maize fodder (Naik et al., 2014), which may be due to the higher DCP and TDN content of the ration (Moghaddam et al., 2009;Naik et al., 2014, Helal 2015. Likewise, Grigorev et al. (1986) showed that replacing 50% of the maize silage with 18kg of hydroponic barley grass increased cows' milk yields by 8.7%, while milk fat was depressed. This improvement may be due to increase in nutrient quality of hydroponic fodder through sprouting. Early research on hydroponic sprout reported the presence of a grass juice factor that improved livestock performance (Finney, 1982;Elvehjen et al., 1934). More recent research has also indicated that hydroponic sprouts are a rich source of nutrient and they contain the grass juice factors that improve the performance of livestock (Nutrigrass, 2007). Adjlane et al. (2016) study on dairy cows supplemented with hydroponic barley (10kg) indicated that milk yield was increased significantly (16.14 vs. 13.49 litre/day). Abd Rahim et al. (2015) were also observed a slight improvement in milk protein, milk fat and total solids in dairy goat but were not significant in sheep supplemented with barley green fodder. A test completed on milk production with a diet of fodder versus one of the normal feeds such as grain, hay or silage showed a vast improvement in milk production and butterfat content. A group of 60 cows on a fodder diet increased their milk production by 10.07%. In addition, the fodder fed group also produced a butterfat content of 14.26% higher as compared to those fed on a regular diet (Ryan, 2003). In another study from Canadian, there was an increase in 3.6kg per day milk production per cow over the lactation period. Furthermore, from South Africa, milking cows dropped 3.6 litres of milk per milking after leaving off the green fodder, which was fed at the rate of 6.8kg per day (Mooney, 2002). Naik et al. (2013) result also revealed that milk yield was increased by 0.5-2.5 litres/animal/day due to the feeding of hydroponic fodder to dairy animals. In Šidagis et al. (2014) study, they were concluded that malt sprouts were increased the whole milk yield and milk fat content, but had no significant influence on milk protein content. Naik et al. (2014) were reported 13.7% increase in the milk yield due to hydroponic maize feeding. These improvements might be due to a stimulated appetite of the cow as a result of the daily feeding of fresh green fodder (Ryan, 2003).  Heins and Paulson, 2016) However, Williams (1956) observed no change in milk production or fat percentage. In another study, Tinley and Bryant (1938) found that the difference in milk yield between the sprout-fed and control groups was not significant. Likewise, Chinnam (2015) in lactating buffalo reported no significant effect on milk production upon feeding hydroponic maize fodder. The conclusion of 8 tests by Bartlett et al. (1938) showed that feeding sprouted maize had no advantage in either milk yield or quality. Marisco et al. (2009) were also found no change in goat milk yield between those fed on hydroponic sprouts and those fed on traditional diets. Sheep milk yield, milk protein, milk fat and total solids were also not affected by feeding hydroponic barley.

Conclusion
Dairy cattle require green fodder for high milk yield. However, it cannot available throughout the year and in some area, it is difficult to have access for green fodder. Thus, hydroponic fodder production has become an alternative way to fulfill this green fodder requirement of the dairy cow. The adoption of this technique has enabled the production of fresh forage from grains without soil. Hydroponic fodder has high nutritive value due to the conversion of complex compounds into simpler and essential form, and activation of enzymes during germination. Thus, it contains high protein, vitamins and minerals which are essential for dairy cows. There were improvements in digestibility and intake of nutrients results in increased milk yields and quality like milk fat of dairy cow on the feeding of hydroponic fodder. In general, research data on dairy cows is limited to determine definitively whether or not feeding the fodder changes production enough to warrant the additional cost. Therefore, this area requires further information to draw a concrete conclusion about feeding hydroponic fodder.