The Effect of Reducing Alfalfa Haylage Particle Size on Cows in Early Lactation

Abstract

The objective of this experiment was to evaluate effects of reducing forage particle size on cows in early lactation based on measurements of the Penn State Particle Separator (PSPS). Eight cannulated, multiparous cows averaging 19 ± 4 d in milk and 642 ± 45 kg BW were assigned to one of two 4 × 4 Latin Squares. During each of the 23-d periods, animals were offered one of four diets, which were chemically identical but included alfalfa haylage of different particle size; short (SH), mostly short (MSH), mostly long (MLG), and long (LG). Physically effective neutral detergent fiber (peNDF) was determined by measuring the amount of neutral detergent fiber retained on a 1.18 mm screen and was similar across diets (25.7, 26.2, 26.4, 26.7%) but the amount of particles >19.0 mm significantly decreased with decreasing particle size. Reducing haylage particle size increased dry matter intake linearly (23.3, 22.0, 20.9, 20.8 kg for SH, MSH, MLG, LG, respectively). Milk production and percentage fat did not differ across treatments averaging 35.5 ± 0.68 kg milk and 3.32 ± 0.67% fat, while a quadratic effect was observed for percent milk protein, with lowest values being observed for LG. A quadratic effect was observed for mean rumen pH (6.04, 6.15, 6.13, 6.09), while A:P ratio decreased linearly (2.75, 2.86, 2.88, 2.92) with decreasing particle size. Total time ruminating increased quadratically (467, 498, 486, 468 min/d), while time eating decreased linearly (262, 253, 298, 287 min/d) with decreasing particle size. Both eating and ruminating per unit of neutral detergent fiber intake decreased with reducing particle size (35.8, 36.7, 44.9, 45.6 min/ kg; 19.9, 23.6, 23.5, 23.5 min/kg). Although chewing activity was 1445 closely related to forage particle size, effects on rumen pH were small, indicating factors other than particle size are critical in regulating pH when ration neutral detergent fiber met recommended levels. Feeding alfalfa haylage based rations of reduced particle size resulted in animals consuming more feed but did not affect milk production. (Key words: rumen, effective fiber, pH, and rumination)Abbreviation key: BWCH = body weight change, DMD = dry matter digestibility, LDR = liquid dilution rate, LG = long treatment containing long harvested haylage, MSH = intermediate short treatment composed of 1/3 parts LG, 2/3 parts SH, MLG = intermediate long composed of 2/3 parts LG, 1/3 parts SH. peNDF = physically effective neutral detergent fiber, PSPS = Penn State Particle Separator, RDOM = rumen degradable organic matter, S gm = geometric standard deviation, SH = short treatment containing rechopped alfalfa haylage, TC = total chewing activity, TLC = theoretical length of cut, X gm = geometric mean length.

Effect of forage particle length on rumen fermentation, sorting and chewing activity of late-lactation and non-lactating dairy cows

“…In E2, total time spent eating and minutes per kilogram of NDFI were not different, whereas a trend for a quadratic effect of minutes per kilogram of DMI was observed; however, with small numerical differences this Suarez-Mena, Zanton and Heinrichs trend is probably not of physiological importance. Kononoff and Heinrichs (2003) and Teimouri Yansari et al (2004) using lactating cows observed a linear increase in eating time per day and minutes per kg of DMI and NDFI as (alfalfa haylage in the first study and alfalfa hay in the second) particle length increased. Nasrollahi et al (2012) also observed an increase of the same variables for greater alfalfa hay particle length, whereas Yang and Beauchemin (2006) observed no differences when barley silage particle length increased.…”

“…Failure to detect differences in DMI has been reported in cows averaging 189 6 38 DIM (Beauchemin et al, 2003); 153 6 7 DIM (Leonardi and Armentano, 2003); 189 6 39 DIM (Yang and Beauchemin, 2006); and 175 6 21 DIM (Nasrollahi et al, 2012). In contrast, other studies with cows averaging 19 6 4 DIM (Kononoff and Heinrichs, 2003) and 81 6 15 DIM (Teimouri Yansari et al, 2004) observed an increase in DMI when forage particle length was reduced (reported DIM were at the beginning of the experiments). In E1, DMI increased numerically as particle length decreased but standard errors were high, which may be the reason for the failure to detect differences.…”

“…Starting at morning feeding on day 11, chewing behavior was visually monitored for 48 h at 2-min intervals, and each activity was assumed to persist for the entire 2-min interval. Data are expressed as eating, ruminating and total chewing (TC; sum of eating and ruminating time) activity (Kononoff and Heinrichs, 2003). On day 13, ruminal contents were sampled at 21, 0, 1, 2, 4, 8 and 12 h after morning feeding, and subsamples were collected at five different rumen locations (dorsal, ventral, anterior, caudal and central), composited and strained through four layers of cheesecloth; pH of the liquid portion was immediately determined using a hand-held pH meter (phTestr 10 BNC, Oakton, Vernon Hills, IL, USA).…”

“…There is, however, a huge range in particles .1.18 mm, as has been defined in other studies. Kononoff and Heinrichs (2003) fed four diets in which TMR X gm differed, but total amount of TMR DM .1.18 mm did not. In that study, total time spent chewing had a tendency and chewing minutes per kilogram of DM intake (DMI) significantly increased when diets with greater X gm were fed; rumen pH did not follow the same trend and had a quadratic effect.…”

“…Accordingly, large particles are believed not to be immediately available for passage from the rumen, having a greater ability to stimulate chewing activity in addition to the chemical composition of feeds. Increasing forage particle length increases chewing time (Kononoff and Heinrichs, 2003;Yang and Beauchemin, 2006), which stimulates saliva secretion (Allen, 1997) in lactating cows. Beauchemin et al (2008) observed that greater proportions of forage dry matter (DM), NDF and longer particle length in a Present address: Novus International, Inc., 20 Research park Drive, St. Charles, MO 63304, USA.…”