The objective of this study was to determine the interactions between alfalfa hay and corn grain particle sizes on nutrient intake, milk yield, milk composition, chewing activity, and ruminal pH of dairy cows. Alfalfa hay was chopped either at 4 cm (long; L) or 1 cm (short; S) theoretical length of cut. Particle size of corn grain was obtained by grinding either at 1 mm (coarse; C) or less than...

We investigated the effect of stage of pregnancy on estimates of breeding values for milk yield and milk persistency in Gyr and Holstein dairy cattle in Brazil. Test-day milk yield records were analyzed using random regression models with or without the effect of pregnancy. Models were compared using residual variances, heritabilities, rank correlations of estimated breeding values of bul...

Twelve multiparous Holstein cows averaging 57 d (36 to 77 d) postpartum at the start of the experiment were utilized in a replicated 4 x 4 Latin square design. Dietary protein supplements were 1) soybean meal, 2) soybean meal plus ruminally protected Lys and Met, 3) corn distillers grains, and 4) corn distillers grains plus ruminally protected Lys and Met. Dry matter intakes were lower for cows...

Heritability estimates, by year of freshening of daughter, were obtained from daughter-dam and granddaughter-granddam regressions using 61,482 triply matched first lactations of artificially sired Holstein cows obtained from the Northeast Dairy Records Processing Laboratory. After adjusting for herd-year-season effects, residual effects may include additive and other genetic effects of the anim...

Estimates of genetic correlations were .17 between first lactation milk yield and concurrent calving interval, .10 between second lactation milk yield and first calving interval, and .82 between first and second milk yields. Corresponding phenotypic correlations were .27, .16, and .58. Heritability estimates were .27 and .25 for first and second lactations and .15 for calving interval. Estimate...

Interval mapping was carried out to identify quantitative trait loci (QTL) for milk production traits in five granddaughter design families of the German Holstein population. Fourteen randomly generated markers spanning the whole of BTA6 and six targeted microsatellite markers from BTA6q21-31 were included in the analysis. In one family a QTL with effects on milk fat yield and milk protein yiel...

The objectives were to study the effects of feeding rolled flaxseed (FLX) to early-lactation dairy cows on milk yield, milk components, and milk fatty acid profiles as well as on measures of cow reproduction. Lactating Holstein cows, on 3 commercial dairies, were fed either an early-lactation ration (CON) or a ration that was similar in protein, energy, and fat content but that included FLX (0....

The aim of this study was to evaluate the effects of repeated oronasal administration of lipopolysaccharide (LPS) on milk composition and the overall productive performance of dairy cows. One hundred pregnant Holstein dairy cows were randomly assigned to two treatment groups (n = 50). 30 cows out of 100 were selected for intensive sampling (n = 15) starting at 28 d before parturition. Cows were...

Results from 12 switchback field trials involving 1216 cows were combined to assess the effects of a protected B vitamin blend (BVB) upon milk yield (kg), fat percentage (%), protein %, fat yield (kg) and protein yield (kg) in primiparous and multiparous cows. Trials consisted of 3 test periods executed in the order control-test-control. No diet changes other than the inclusion of 3 grams/cow/ ...

Birdsfoot trefoil (Lotus corniculatus) increases milk yield of dairy cows. An indoor feeding experiment using Friesian dairy cows in mid lactation was conducted to determine what proportions of the milk yield and composition changes were due to the condensed tannins (CT) in Lotus, and what proportions were due to factors associated with legumes (higher herbage intake and forage quality). Cows w...