Effect of harvest time and physical form of alfalfa silage on chewing time and particle size distribution in boli, rumen content and faeces

Abstract

<jats:p>The study examined the effects of physical form and harvest time of alfalfa silage on eating and ruminating activity and particle size distribution in feed boli, rumen content and faeces in dry cows. The alfalfa crop was harvested at two stages of growth (early: NDF 37%, late: NDF 44% in dry matter (DM)), and from each harvest, a chopped (theoretical cutting length: 19 mm) and an unchopped crop was ensiled in bales. The silages were fed restrictively to four rumen cannulated non-lactating Jersey cows (391 ± 26 kg) in a 4 × 4 Latin square design. The cows were fed restrictively 80% of their<jats:italic>ad libitum</jats:italic>intake twice daily. Chewing activity was recorded for 96 h continuously. Swallowed boli, rumen content, rumen fluid and faeces samples were collected, washed in nylon bags (0.01 mm pore size) and freeze-dried before dry sieving through 4.750, 2.360, 1.000, 0.500 and 0.212 mm pore sizes into six fractions. The length (PL) and width (PW) of particles within each fraction was measured by the use of image analysis. The eating activity (min/kg dry matter intake (<jats:italic>P</jats:italic>&lt; 0.01) and min/kg NDF (<jats:italic>P</jats:italic>&lt; 0.05)) was affected by harvest time. The mean ruminating time (min/kg DM) was affected by harvest time (<jats:italic>P</jats:italic>&lt; 0.01), physical form (<jats:italic>P</jats:italic>&lt; 0.05) and NDF intake per kg BW (<jats:italic>P</jats:italic>&lt; 0.01). The proportion of washed particle DM of total DM in boli, rumen content, rumen fluid and faeces was affected by harvest time (<jats:italic>P</jats:italic>&lt; 0.01) and highest by feeding late-harvested alfalfa silage. Two peaks on the probability density distribution function (PDF) of PW and PL values of boli, rumen content and faeces were identified. Chopping of the silage decreased the mean PL and PW, the most frequent PL (mode) and 95% percentile PL and PW values in boli. In the rumen content, chopping increased the mean PW (<jats:italic>P</jats:italic>&lt; 0.05). The dimension sizes of faeces particles were not significantly affected by chopping. The mode PW value was lower in rumen content and faeces than in boli (<jats:italic>P</jats:italic>&lt; 0.001), and the mode PL value was higher in boli and lower in faeces compared with rumen contents (<jats:italic>P</jats:italic>&lt; 0.001). In conclusion, the mean total chewing activity per kg NDF decreased due to chopping and early harvest time. The mean PL and PW in boli decreased due to chopping and late harvest. The two peak values on the PDF (PL) and PDF (PW) of boli, rumen content and faeces particles are most likely related to the leaf and the stem residues.</jats:p>

Particle size alterations of feedstuffs during in situ neutral detergent fiber incubation

“…Grinding feedstuffs before in situ rumen incubation is done to improve representative sampling and to attain Dacron bag residues with particle size dimensions that reflect those of particles retained in the rumen in an in vivo situation. Using particle dimensions of washed feces particles for estimation of dimensions in particles escaping the rumen (Jalali et al, 2012a) showed that the screen size of 1.5 mm resulted in biologically realistic particle dimensions of Dacron bag residues after in situ rumen incubation: PL and PW for I00, I24, and I288 fractions from grass and alfalfa silages (Table 4) were about twice as high as PL (1.2 mm) and PW (0.2 mm) of washed feces particles from either sheep fed grass silage (Jalali et al, 2012a), small ruminants fed grass hay or grass seed straw (PL = 1.1 mm; PW = 0.2 mm; Jalali et al, 2012b), or cattle fed alfalfa silage (PL = 1.2 mm; PW = 0.3 mm; Kornfelt et al, 2013).…”

Evaluating Fecal Sieving Tool as an Indicator of Feed Valorization and the Impact of Feeding Strategy on Dairy Cow Performance under Farm Conditions

“…To describe the feeding situation and its efficiency under field condition, fecal PS evaluation might be a useful tool [21] [22] [23]. The fecal PS distribution has been measured using dry sieving [16] [15] or wet sieving technics [13] [14].…”

Intake, rumen fermentation and apparent digestibility of Aerbasi cashmere goats fed corn stover, caragana and their mixture on the Mongolian plateau

“…The ADL content in MT3 (22.82% of DM) was lower than that in CA (24.72% of DM), but higher than in the other treatments. Due to the difficulty in digesting ADL, it stayed in the rumen for a long period [28]. Particles are chewed by cashmere goats repeatedly, such that the number of particles and surface area of the cell walls are increased, in turn increasing the chance that bacteria can reach the fibre and colonise it [29].…”