Yield and sensory properties of cheese made with milk from Holstein or Montbeliarde cows milked twice or once daily

The aim of this study was to evaluate the milk properties and the yield and sensory properties of Cantal cheese made with milk from Holstein or Montbéliarde cows milked once or twice daily. Sixty-four grazing cows [32 Holstein (H) and 32 Montbéliarde (M) cows] in the declining phase of lactation (157 d in milk) were allocated to 1 of 2 equivalent groups milked once daily (ODM) or twice daily (TDM) for 7 wk. The full-fat raw milk collected during 24 h from the 4 groups of cows (M-TDM, M-ODM, H-TDM, and H-ODM) was pooled and processed into Cantal cheese 4 times during the last 4 wk of the experimental period. In all, 16 cheeses were made (2 milking frequencies x 2 breeds x 4 replicates) and analyzed after a ripening period of 15 and 28 wk. The results showed that for both breeds, the pooled milk content of fat, whey protein, casein, total protein, and phosphorus as well as rennet clotting time and curd firming time were significantly higher with ODM cows, whereas the casein-to-total protein ratio was lower, and lactose, urea, calcium, and free fatty acids contents of milk remained unchanged. The acidification and draining kinetics of the cheese as well as cheese yields and the chemical and rheological properties of the ripened cheese were not significantly modified by milking frequency. For both breeds, the cheeses derived from ODM cows had a slightly yellower coloration but the other sensory attributes, except for pepper odor, were not significantly affected by milking frequency, thereby demonstrating that ODM does not have an adverse effect on the sensory properties of Cantal cheese. Compared with that of Holstein cows, milk from Montbéliarde cows resulted in a higher cheese yield (+1.250 kg/100 kg of milk) and ripened cheeses with lower pH, dry matter, calcium, sodium chloride, and water-soluble nitrogen concentrations. These cheeses had also a less firm and more elastic texture, a more acidic taste, and a yogurt/whey aroma.

Milking of cows in late pregnancy: milk production during this period and during the succeeding lactation

Fifteen lactating cows were milked throughout pregnancy, and the effects on milk performance were studied during this period and during the succeeding lactation, relative to 11 conventionally managed cows (2 months dry before calving) as controls. During the last 2 months of pregnancy, only nine cows did not dry off spontaneously. Protein and fat concentrations in milk increased rapidly, but the concentration of lactose, corrected for milk yield, did not change. The ratios of individual caseins to total protein decreased with the quantity of milk produced, but only for yields below approximately 6 kg/d. The relative proportion of kappa-casein tended to decrease in the last milkings. During the succeeding lactation (first 15 weeks after calving and first 6 weeks of grazing) continuously milked cows yielded 4 kg milk/d less than the cows of the other group. The protein content of their milk was higher (2-3 g/kg depending on the period) than that of the control group, and the lactose content tended (P less than 0.10) to be lower. Changes in the relative proportions of nitrogenous fractions with time were not different in the two groups. Differences between the two groups in the concentration of protein in milk, and in the concentration of glucose and non-esterified fatty acids in the plasma, suggest a better energy balance for the continuously milked cows during the succeeding lactation.

Plasma osteocalcin concentrations in cows around parturition. The influence of a regular versus a very short dry period

Plasma Ca, P, Mg and OC concentrations were compared between 2 groups of Holstein cows around 2nd calving. Thirteen cows were milked until their daily milk production was lower than 2 kg, which occurred 4 d before parturition. The control group (8 cows) was normally dried 8 weeks before the expected time of calving. Apart from the week following the initiation of the dry period where plasma OC concentrations were significantly lower in dried cows than in the control group (which would indicate lower bone remodeling in dried cows), no significant difference concerning Ca, P, Mg and OC concentrations were observed between the 2 groups of cows. This indicates that the only lack of 1 8-week-long dry period probably has no major immediate effect upon Ca and bone metabolism in young dairy cows given a convenient Ca and P daily intake. Nevertheless, the lack of the dried period might protect the cow against parturient hypocalcemia: the decrease in plasma Ca and P concentrations observed 12 h after calving was less intense in non-dried cows than in controls.

Body composition of dairy cows according to lactation stage, somatotropin treatment, and concentrate supplementation

Body weight, condition score, deuteriated water dilution space, estimated body lipids and proteins, and calculated energy and protein balances were determined in 24 multiparous Holstein cows at wk 1, 7, 20, and 39 after parturition. Cows received two levels of energy concentrate (high and low groups) from wk 3. The objective was to estimate changes in body composition as affected by stage of lactation, concentrate level, and bST administration or placebo from wk 9 in a 2 x 2 factorial design. Cows from high and low energy groups lost 25 and 35 kg of body lipids and 3.3 and .5 kg of body proteins, respectively, during the first 7 wk of lactation. During the end of the winter period (wk 8 to 20), control and bST-injected cows lost 8.5 and 21.1 kg of body lipids, respectively. During the grazing period (wk 20 to 39), bST-injected cows gained more BW (34 kg), water (36 kg), and estimated proteins (5.8 kg) and lost more condition score (-.2 units) and estimated lipids (-11.5 kg) than controls. Using data from control periods, it was calculated that 1 unit change in body condition score corresponded to changes of 35 to 44 kg in BW (corrected for estimated gut content variation), 21 to 29 kg in body lipids, and 200 to 300 Mcal in body energy. One kilogram of corrected BW change corresponded to a change of 4.3 or 5.5 to 5.9 Mcal in body energy when calculated from cumulative energy balances or body components, respectively.

The influence of physiological state and dietary nitrogen supply on digestion in the dairy cow

The effects of N supply on digestion were compared in cows in late pregnancy vs early lactation. Two groups of four and one group of three dairy cows received, during a digestion trial, corn silage-concentrate diets (65:35) differing in N supply. Concentrates were formulated so that diets were either insufficient (Diet 1) or sufficient (Diets 2 and 3) in ruminally fermented N and either insufficient (Diets 1 and 2) or sufficient (Diet 3) in protein digestible in the intestines. Experimental periods were 3 wk before and 3 wk after parturition. Organic matter digestibilities were 69.8, 73.1 and 72.5% in late pregnancy vs 64.9, 69.8 and 70.8% in early lactation for Diets 1, 2 and 3, respectively. Digestibility was higher (P less than .05) in late pregnancy than in early lactation. Differences between physiological states were attributed to differences in ruminal digestibility and in fiber digestibility. These differences were not explained by a reduction in large particle retention time, but in situ DM disappearance was reduced in early lactation. Ruminal protozoa concentration and the acetate: propionate ratio decreased between pregnancy and lactation. The duodenal non-ammonia N:N intake ratio was higher for Diet 1 than for Diets 2 and 3, 1.20, .97 and .94, respectively, but it did not vary between physiological states. In conclusion, some of the negative consequences of a shortage in degraded N are more dramatic in early lactation than in late pregnancy.