Maize silage and Italian ryegrass silage as high-energy forages in organic dairy cow diets: Differences in feed intake, milk yield and quality, and nitrogen efficiency

Abstract

During the winter feeding period in organic dairy production systems in the alpine and pre-alpine regions of Austria and its neighboring countries, maize silage is an energy-rich forage that is regularly included in grass-silage-based diets to improve the energy supply of the cows. Italian ryegrass (Lolium multiflorum Lam.) is also a high-energy fodder grass popular as forage for dairy cows, but it is rarely cultivated in Austrian organic agriculture. The two crops differ in their cultivation demands and characteristics. Italian ryegrass establishes rapidly and may reduce the risk of soil erosion. Italian ryegrass would be a beneficial addition to crop rotation, which is an essential tool in successful organic farming. In a 15-week feeding trial, Italian ryegrass silage and maize silage were fed to 22 lactating Holstein dairy cows. Organically produced Italian ryegrass silage and maize silage were included at a rate of 40% [of dry matter (DM)] in grass-silage-based mixed basal diets. The mixed basal diets were supplemented with modest amounts of additional concentrates (2.7-3.0 kg DM day − 1 ). Owing to the higher energy content of maize silage as compared to Italian ryegrass silage, the maize diet provided more energy [6.3 MJ net energy for lactation (NEL) kg − 1 DM] than the ryegrass diet (6.15 MJ NEL kg − 1 DM). The protein supply of the maize diet and the ryegrass diet was intended to be equal, but in fact the protein content of the maize diet was significantly lower (122 g crude protein kg − 1 DM) than that of the ryegrass diet (141 g kg − 1 DM). When the maize diet was fed, feed intake, milk yield and milk protein content were significantly higher as compared to the ryegrass diet. Also, intake of crude protein was significantly lower when feeding the maize diet, and in combination with the higher milk protein yield, this enabled an efficiency of gross nitrogen (N) utilization as high as 0.304. This level of N efficiency can be considered as above average and was significantly and considerably higher than the level of 0.259 observed when the ryegrass diet was fed. Therefore, maize silage upholds its reputation as an ideal energy-rich component in grass-silage-based dairy cow diets.

Modification of the sterol profile in milk through feeding

“…Several researchers have documented the effect of various feed types on the resulting FA profiles of milk. These experiments have shown that cattle breed, FA content in the feed, and ruminal digestion are all factors that can influence the FA content in milk (Egger et al, 2009;Hristov et al, 2011;Baldinger et al, 2014;Samková et al, 2014). For example, Steinshamn (2010) reviewed experimental data from feeding trials using a variety of grassland legumes such as white clover, red clover, and lucerne and demonstrated that, in general, a difference in feed resulted in changes to the FA composition of milk when compared with the control.…”

Effects of using different roughages in the total mixed ration inoculated with or without coculture of Lactobacillus acidophilus and Bacillus subtilis on in vitro rumen fermentation and microbial population

“…Corn silage is an energy-rich forage that is often included in grass-silage-based diets to improve the energy supply in cows. Moreover, the inclusion of corn silage in the diet increases the supply of fermentable carbohydrates in the rumen [ 8 ]. In Korea, the production of IRG and corn accounts to 53.1% and 4.4%, respectively, of the total forage produced in 2013 [ 9 ].…”

Nutritive value of ensiled Italian ryegrass and winter cereal mixture

“…The use of drought resistance corn breed (Lathrop & Namuth, 2011), whole crop sorghum silage (Colombini et al, 2015;Cattani et al, 2017;Khosravi et al, 2018), high sugar forage sorghum silage (Su-jiange et al, 2016) as well as sorghum and Sudan grass in a drought prone region (Getachew et al, 2016) is an indicator for imminent need of alternative forage. The use of cereals silage is also popular now (Van Duinkerken et al,1999;Bernard et al, 2002;Baldinger et al, 2011Baldinger et al, , 2014Harper et al, 2017, Orosz et al, 2019. However, the use of Italian ryegrass and winter cereals for silage is not reported until today.…”

“…However, the use of Italian ryegrass and winter cereals for silage is not reported until today. Italian ryegrass (Lolium multiflorum) is one of the fastest growing grass species with excellent nutritional qualities particularly high fiber digestibility (NDFd), CP and sugar content (Baldinger et al, 2011(Baldinger et al, , 2014Field crop news, 2014;DLF seeds, UK, 2018;Byron Seeds, LLC, 2019). Field crop news (2014) reported that the yield of Italian ryegrass is not as high as winter cereals such as oats, but nutrient quality and palatability is greater which makes it more suitable for high producing dairy cow feed.…”

“…The high energy content in rye, barley and triticale silage (NRC, 2001) together with Italian ryegrass could boost the energy content of ensiled mixtures. Additionally the high NDF digestibility, crude protein and sugar content as well as palatability of Italian ryegrass (Baldinger et al, 2011(Baldinger et al, , 2014 could improve the intake and digestibility of cereals. High fiber digestibility can improve the dry matter intake (DMI) and milk production of the dairy cow (Raffrenato & Van Amburgh, 2010;Grant, 2012).…”