• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.725-730
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• 2003

This study was conducted to evaluate the adequacy of an alternative a.m.-p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 8,309 p.m. milking weights and 6,767 a.m. milking weights from 72 Holstein cows raised at N.L.R.I. were collected between October 2000 and November 2001. Ratios were computes for daily milk yield to a.m. and p.m. milking weights(direct yield ratios) and ratios of a.m. and p.m. milking weights to daily milk yield (inverse yield ratios). Analysis of variance indicated that the milking interval is the most important source of variation for yield ratios. Adjustment factors for estimating daily milk yield from single milking weights were derived through regression analysis of direct and inverse yield ratios on the length of the milking interval. Daily milk yield was estimated more precisely and accurately when adjustment factors were used than when single milking weights were doubled. In conclusion, alternative recording of a.m. and p.m. milking weights led to reliable estimates of milk yields.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.707-718
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• 2004

This study was conducted to evaluate the adequacy of an alternative a.m. - p.m. testing scheme for milk yield in comparison with the official test method based on weighing two milkings within 24 h. A total of 8,309 p.m. milking weights and 6,767 am. milking weights from 72 Holstein cows raised at N.L.R.I. were collected between October 2000 and November 2001. Seven statistical models were fitted to the data to derive formulas for estimating daily milk yields from morning or evening yields. In general, use of evening milkings less accurately estimated than did use morning rnilkings. Although the models do not differ much in the correlations between estimated and true daily milk yields, systematic under- and overestimation of daily milk yields were observed in all models with the exception of model 7, which accounted for heterogeneous variances by parity class, milking interval class, and lactation stage by fitting separate regression formulas within each combination of three factors.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.516-519
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• 2009

This study was conducted to investigate the effects of replacing whole crop corn silage (WCCS) with whole crop rice silage (WCRS) in the total mixed ration (TMR) on nutrient intake, milk yield and its composition in Holstein cows. The Chucheong rice variety (Oryza sativa L. Japonica) and corn (Pioneer 32 P75) were harvested at yellow-ripe stage and were ensiled in round bales and in trench silos, respectively. Two TMR containing either WCCS or WCRS were prepared. These diets were randomly assigned to 16 midlactating Holstein cows (8 cows per treatment) and were fed for 120 days. The first 20 days were used for dietary adaptation and for the next 100 days daily feed intake, milk yield and its composition were recorded. The pH, lactic acid, NDF, ADF, CP, Ca and P contents were similar in WCRS and WCCS. The DM, ash and EE contents of WCRS were greater compared with WCCS. Nutrient (DM, NDF, TDN and CP) intakes were similar in cows fed WCCS- and WCRS-based TMR. Daily and 4% fat corrected milk yield were not affected by the treatments. Milk composition (percent milk fat, protein, lactose and total solids) was similar in cows fed either WCCS- or WCRSbased TMR. The concentration of milk urea N was greater in cows fed WCRS-based TMR than those fed WCCS-based TMR. In conclusion, round-baled WCRS can replace WCCS in the diet of mid- to late-lactating Holsteins without any deleterious effects on feed consumption, milk yield and its composition. The present findings raise the possibility that WCRS can be used as an alternative roughage source in the diets of dairy cows in countries with surplus rice production.