Effects of feeding algal meal high in docosahexaenoic acid on feed intake, milk production, and methane emissions in dairy cows

Abstract

This study examined effects on milk yield and composition, milk fatty acid concentrations and methane (CH4) emissions when dairy cows were offered diets containing different amounts of algal meal. The algal meal contained 20% docosahexaenoic acid (DHA) and cows were offered either 0, 125, 250, or 375 g/cow per d of algal meal corresponding to 0, 25, 50, or 75 g of DHA/cow per d. Thirty-two Holstein cows in mid lactation were allocated to 4 treatment groups, and cows in all groups were individually offered 5.9k g of dry matter (DM) per day of concentrates [683 g/kg of cracked wheat (Triticum aestivum), 250 g/kg of cold-pressed canola, 46 g/kg of granulated dried molasses, and 21 g/kg of mineral mix] and ad libitum alfalfa (Medicago sativa) hay. The algal meal supplement was added to the concentrate allowance and was fed during the morning and afternoon milking, whereas the alfalfa hay was fed individually in pens. Cows were gradually introduced to their diets over 7d and then fed their treatment diets for a further 16d. Dry matter intake and milk yield were measured daily, and milk composition was measured on a sample representative of the daily milk yield on Thursday of each week. For the last 2d of the experiment, cows were individually housed in respiration chambers to allow measurement of CH4 emissions. Dry matter intake, milk yield and milk composition were also measured while cows were in the respiration chambers. Cows ate all their offered concentrates, but measured intake of alfalfa decreased with increasing dose of DHA by 16.2, 16.4, 15.1, and 14.3 kg of DM/d, respectively. Milk yield (22.6, 23.5, 22.6, and 22.6 kg/cow per d) was not affected by DHA dose, but milk fat concentrations (49.7, 37.8, 37.0, and 38.3g/kg) and, consequently, milk fat yields (1.08, 0.90, 0.83, and 0.85 kg/d) decreased with addition of DHA. The feeding of algal meal high in DHA was associated with substantial increases in the concentrations of DHA (0.04, 0.36, 0.60, and 0.91 g/100g of milk fatty acids) and conjugated linoleic acid C18:2 cis-9,trans-11 (0.36, 1.09, 1.79, and 1.87 g/100g of milk fatty acids). Addition of DHA did not affect total emissions of CH4 (543, 563, 553, and 520 g/cow per d), nor emissions in terms of milk production (24.9, 22.1, 24.3, and 23.4 g of CH4/kg of milk), but emissions were increased with respect to total intake (22.6, 23.5, 24.5, and 24.4 g of CH4/kg of DM). These findings indicate that CH4 emissions were not reduced when dairy cows were fed a forage-based diet supplemented with DHA from algal meal.

Spirulina platensis (Arthrospira spp.): A Potential Novel Feed Source For Pasture-Based Dairy Cows

“…The positive impact of Spirulina platensis on milk yield was also confirmed by the study conducted by Šimkus et al [52]. Other studies conducted elsewhere however found no effect of feeding algal-based diet on milk yield [53][54][55][56] (Table 3).…”

Omega-3 supplementation, milk quality and cow immune-competence

“…In the present study the form of algae supplementation was protected similarly to that used by Stamey et al (2012). Similarly, Moate et al (2013), offering different amounts of algal meal to lactating cows, found no alterations on milk yield although milk fat yield decreased with the addition of DHA. On the contrary, other authors (Franklin et al, 1999;Boeckaert et al, 2008;Hostens et al, 2011), supplementing cows with unprotected marine algae observed a reduction in dry matter intake (DMI) and milk yield.…”

Reducing the carbon footprint of Australian milk production by mitigation of enteric methane emissions

“…Figure 4 depicts daily DMI and daily methane production data from 220 cows from eight experiments using Holstein-Friesian cows (Grainger et al 2008b;2010a;Moate et al 2013;Williams et al 2013;Deighton et al 2014b; and three unpublished experiments, using the same methodology). The cows were at different stages of lactation and were fed a wide variety of diets containing in excess of 70% forage (pasture, pasture hay, pasture silage, or lucerne hay) and between 0% and 30% cereal grain (barley or wheat), with none of these diets containing any known methane mitigants.…”