Effects of different sources of carbohydrates on intake, digestibility, chewing, and performance of Holstein dairy cows

Table 5 Chewing activity of cows fed on three total mixed rations of three total mixed rations containing three different sources of non-fiber carbohydrates

Items	Treatments¹			SEM	P value
Items	B	BC	BB	SEM	P value
Eating, min/d	257.8^a	232.8^b	249.4^ab	10.272	0.045
Rumination, min/d	338.9^b	286.1^c	356.1^a	7.430	<0.001
Total chewing activity, min/d	596.7^a	518.9^b	605.5^a	10.482	<0.001
Chewing behaviour per different nutrients, min/kg
Eating
DMI	12.19	11.08	11.174	0.552	0.200
NDF	33.70^a	30.00^b	29.10^b	0.972	0.004
peNDF_m²	50.55^a	45.29^b	43.45^b	2.430	0.033
peNDF _{> 8}³	97.93^a	86.75^b	92.97^ab	4.431	0.002
peNDF _{> 1.18}⁴	50.85	45.20	43.37	4.294	0.063
NFC	31.36	28.46	29.42	1.154	0.088
Starch	54.97^b	54.78^b	76.98^a	4.452	<0.001
NDSC⁵	89.52^a	69.70^b	55.55^c	3.762	<0.001
Rumination
DMI	16.03^a	13.61^b	15.95^a	0.350	<0.001
NDF	44.30^a	36.87^b	41.55^a	1.561	<0.001
peNDF_m	66.45^a	55.66^b	62.04^a	1.902	0.003
peNDF _{> 8}	128.74^a	106.61^b	132.74^a	5.242	0.009
peNDF _{> 1.18}	66.84^a	55.55^b	61.93^a	1.615	0.002
NFC	41.23^a	34.98^b	42.09^a	0.812	<0.001
Starch	72.26^b	67.32^b	109.91^a	6.692	<0.001
NDSC	117.67^a	85.66^b	79.31^c	3.833	<0.001
Total chewing activity
DMI	28.23^a	24.69^c	26.13^b	0.671	<0.001
NDF	78.00^a	66.87^c	68.06^b	2.031	<0.001
peNDF_m	117.00^a	100.95^b	101.61^b	3.292	<0.001
peNDF _{> 8}	216.41^a	193.35^b	225.71^a	15.320	<0.001
peNDF _{> 1.18}	117.69^a	100.76^b	101.43^b	3.462	0.006
NFC	72.59^a	63.43^c	68.94^b	1.752	<0.001
Starch	127.23^b	122.09^b	186.88^a	7.860	<0.001
NDSC	207.19^a	155.36^b	134.86^c	6.744	<0.001

^{a, b, c}Means within a row with different subscripts differ (P < 0.05).
¹Treatments were diets containing barley + basal diet (B), barley and corn + basal diet (BC), and barley and beet pulp + basal diet (BB).
²peNDF_m = physically effective NDF, based on DM retained on sieve 1.18 mm [13].
³peNDF_>8 = physically effective NDF, determined as the proportion of DM retained on sieves of the original version of Penn State particle separator [10].
⁴peNDF_>1.18 = physically effective NDF, determined as the proportion of DM retained on sieves of the new version of Penn State particle separator [11].
⁵NDSC = Neutral detergent soluble carbohydrate.

ISSN: 2049-1891