Milk Production, Milk Quality, and Behaviour of Dairy Cows Grazing on Swards with Low and High Water-Soluble Carbohydrates Content in Autumn: A Pilot Trial

Abstract

Grazing ruminant systems can be sustainably intensified by improving efficiency while reducing their environmental impact. The objective of the present study was to examine the potential of pastures differing in water-soluble carbohydrates (WSC) and crude protein (CP) contents to affect milk production and composition as well as the behaviour of cows grazing perennial ryegrass (PRG) swards. By modifying the nitrogen (N) fertilisation rate (83 and 250 kg/ha per year) and the defoliation frequency (two or three leaves per tiller) in combination with cultivar selection (high-sugar vs. standard cultivars), we obtained two swards differing in WSC and CP contents. The two contrasting swards were each grazed by six dairy cows in nine daily strips in autumn. Pasture samples were collected to determine herbage mass and quality. Cow behaviour was recorded by direct observation. Herbage offered and apparently consumed were similar between swards (averaging 37.3 and 18.2 kg/cow, respectively), although the residual was lower in the high-sugar sward (1735 vs. 2143 kg/ha). Cows spent less time grazing in the high-sugar sward (66.9% v. 71.6%), but the rumination times was similar (14.6%). Milk production and composition were similar between groups, suggesting that high-quality pastures would require a greater difference in nutritional composition to affect animal performance.

In Vitro Fermentation Patterns and Methane Output of Perennial Ryegrass Differing in Water-Soluble Carbohydrate and Nitrogen Concentrations

“…This resulted in differences in chemical composition that were mentioned above, and in terms of in vitro N metabolism, reduced NH 3 -N at both 4 h and 24 h of incubation and improved NUE. Coincidentally, cows grazing the same HS pastures that were sampled in autumn for this study presented a lower milk urea concentration, compared with the LS pasture, although the difference did not reach statistical significance [59]. However, there was no effect on microbial N yield, N digestibility, nor EMPS.…”

A review on the potentials of using feeds rich in water‐soluble carbohydrates to enhance rumen health and sustainability of dairy cattle production

“…Although only one study showed decreased milk production when dairy cows were fed WSC-rich hay, 73 most studies testing WSC-rich forages observed no change in milk yield 58,61,71,74,75 or an increase. 30,63,76 Especially in early lactation, when voluntary DM intake potential is more restricted, feeding solely voluminous WSC-rich forage might not be sufficient to overcome the negative energy balance in a reasonable time frame.…”

“…68,70 The results suggest that sugars in the diet compensate for the lack of lipogenic substrates for milk fat synthesis, such as acetate and butyrate, which are low during starch-rich feeding. It appears that, because milk fat concentration is generally higher under foragebased feeding, 50,58,61,71 the effects of feeding WSC on milk fat can only become visible in starch-rich diets when more than 2 kg of WSC (except lactose) 72 is ingested (Table 2).…”

The The Effect of MRD (Milk of Red Rice and Dates) Composition on the Degradation Stability of Milk Dyes and The Content of Milk Microbial Contamination

“…Maka dari itu, penggalakan konsumsi susu harus terus dilakukan, karena selain kandungan gizinya tinggi, susu juga dapat berperan sebagai pengikat polutan. Komponen utama dalam susu hewani yaitu protein, vitamin, laktosa, dan lemak (Merino, et al, 2019). Disamping itu susu mengandung komponen mikro dan makro yang sangat dibutuhkan oleh tubuh.…”