Effect of dietary sugar concentration and sunflower seed supplementation on lactation performance, ruminal fermentation, milk fatty acid profile, and blood metabolites of dairy cows

Abstract

Previous research has shown that both sunflower seed (SF) and sucrose (SC) supplementation can result in variation in milk fat concentration and composition, possibly due to altered fermentation patterns and biohydrogenation of fatty acids in the rumen. The objective of this study was to determine the effects of different sugar concentrations with or without SF supplementation on lactation performance, ruminal fermentation, and milk fatty acid profile in lactating dairy cows. Eight multiparous Holstein dairy cows (body weight=620±15kg, 60±10 d in milk, mean ± standard deviation) were randomly assigned to treatments in a replicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Each 21-d period consisted of a 14-d diet adaptation period and 7-d collection period. Dairy cows were fed 1 of the following 4 diets: (1) no additional SC without SF supplementation (NSC-SF), (2) no additional SC with SF supplementation (NSC+SF), (3) SC without SF supplementation (SC-SF), and (4) SC with SF supplementation (SC+SF). The diets contained the same amount of forages (corn silage and alfalfa hay). Four isonitrogenous and isoenergetic diets were formulated by replacing corn grain with SC and SF and balanced using change in proportions of canola meal and sugar beet pulp. No interaction was detected between SC and SF supplementation with respect to dry matter intake, milk yield, and composition. A tendency was found for an interaction between inclusion of SC and SF on energy-corrected milk with the highest amount in the SC-SF diet. Ruminal pH and the molar proportion of acetate were affected by SC inclusion, with an increase related to the SC-SF diet. Diets containing SF decreased the concentrations of short-chain fatty acids (4:0 to 10:0) and medium-chain fatty acids (12:0 to 16:0) in milk fat. The addition of SC tended to decrease the concentration of total trans-18:1. These data provide evidence that exchanging SC for corn at 4% of dietary dry matter influenced milk fat content and rumen pH, resulting in a tendency for decreased concentration of trans-18:1 in milk fat. Sucrose alone did not alter the milk fatty acid profile when cows were fed a combination of unsaturated fat and sugar, although several significant interactions between sugar and unsaturated fat were observed.

Liquid molasses interacts with buffers to affect ruminal fermentation, milk fatty acid profile, and milk fat synthesis in dairy cows fed high-concentrate diets

“…In the present experiment, total VFA concentration in the rumen was not altered by LM inclusion, which agrees with previous studies (Penner and Oba, 2009;Razzaghi et al, 2016). Cows fed the BFM-supplemented diets showed a trend for increased total VFA concentration in the rumen.…”

“…The effects of dietary inclusion of sugars via sucrose or molasses (dried or liquid) on DMI have been inconclusive across the literature. Previous studies conducted with lactating dairy cows reported no effect of sources rich in disaccharides on DMI either in typical (Razzaghi et al, 2016) or high-concentrate diets (Martel et al, 2011), whereas others (Broderick et al, 2008;Penner and Oba, 2009) observed increased DMI. A possible explanation for the positive effect of LM on DMI could be related to improved diet palatability (Khalili and Huhtanen, 1991).…”

“…One strategy to decrease dietary starch concentration while maintaining lactation performance is to replace starch with sugars. Previous research showed that sugar sources such as sucrose or molasses can increase feed intake (Broderick and Radloff, 2004;Broderick et al, 2008) and milk fat yield (Penner and Oba, 2009;Razzaghi et al, 2016). Replacing starch with sugars in diets of dairy cows did not increase the risk of ruminal acidosis (Penner and Oba, 2009) or induce milk fat depression (Martel et al, 2011), despite sugar fermentation being faster in the rumen than starch (Chamberlain et al, 1993).…”

“…Intake of buffers and soluble sugars could also affect the buffering capacity and absorptive mechanisms associated with decreased ruminal acidity (Dijkstra et al, 2012;Gao and Oba, 2016). Moreover, dietary inclusion of sucrose and buffers decreased the proportion of total trans-18:1 FA in milk fat (Kalscheur et al, 1997;Razzaghi et al, 2016) and increased milk fat concentration (Broderick et al, 2008;Iwaniuk et al, 2015). Nevertheless, to our knowledge, data on how sugar sources and buffer supplementation could interact to change ruminal fermentation and milk FA profile are lacking.…”

Using brown midrib 6 dwarf forage sorghum silage and fall-grown oat silage in lactating dairy cow rations

“…The higher ethanol soluble carbohydrate concentration in the sorghum silage versus corn silage in the current study may have contributed to the increased milk fat, although the increase in sugar was only around 0.25% of the diet DM due to the sorghum silage, so the effect may have been small. Razzaghi et al (2016) reported higher fat content and lower total milk trans-18:1 FA with a sucrose treatment. It is known that increases in trans-10 18:1 milk FA are positively related to milk fat depression for cows fed a low-fiber, high-oil diet (Rico and Harvatine, 2013).…”