Maurizio Capelletti

Hydrogen and oxygen stable isotope fractionation in body fluid compartments of dairy cattle according to season, farm, breed, and reproductive stage.

Environmental temperature affects water turnover and isotope fractionation by causing water evaporation from the body in mammals. This may lead to rearrangement of the water stable isotope equilibrium in body fluids. We propose an approach to detect possible variations in the isotope ratio in different body fluids on the basis of different homoeothermic adaptations in varying reproductive stages. Three different reproductive stages (pregnant heifer, primiparous lactating cow, and pluriparous lactating cow) of two dairy cattle breeds (Italian Friesian and Modenese) were studied in winter and summer. Blood plasma, urine, faecal water, and milk were sampled and the isotope ratios of H (2H/1H) and O (18O/16O) were determined. Deuterium excess and isotope-fractionation factors were calculated for each passage from plasma to faeces, urine and milk. The effects of the season, reproductive stages and breed on δ 2H and δ 18O were significant in all the fluids, with few exceptions. Deuterium excess was affected by season in all the analysed fluids. The correlations between water isotope measurements in bovine body fluids ranged between 0.6936 (urine-milk) and 0.7848 (urine-plasma) for δ 2H, and between 0.8705 (urine-milk) and 0.9602 (plasma-milk) for δ 18O. The increase in both isotopic δ values in all body fluids during summer is representative of a condition in which fractionation took place as a consequence of a different ratio between ingested and excreted water, which leads to an increased presence of the heavy isotopes. The different body water turnover between adult lactating cattle and non-lactating heifers was confirmed by the higher isotopic δ for the latter, with a shift in the isotopic equilibrium towards values more distant from those of drinking water.

Evaluation of milk enzymes and electrolytes, plasma metabolites, and oxidative status in twin cows milked in an automatic milking system or twice daily in a conventional milking parlor.

The aim of this paper was to evaluate the effects of automatic milking (AM) on milk enzymes and minerals related to mammary epithelial integrity in comparison with twice-daily conventional milking (CM). One cow from each of 6 pairs of twins was assigned to be milked with AM or with CM throughout first lactation. Milk production was recorded and milk samples were collected at 4, 11, 18, 25, 32, and 39 wk of lactation (WOL) to determine fat and protein content, somatic cell count, pH, plasminogen (pl) and plasmin (Pl) activities, Na, K, and Cl. Body condition score was monitored; blood samples were collected to determine energy-related metabolites in the first third of lactation (14 WOL), and plasma oxidative status throughout lactation. Overall mean and standard deviation of milking frequency (MF) in AM were 2.69 and 0.88, respectively. Milk production, fat and protein contents, and somatic cell count did not differ between milking systems. The pl and pl+Pl activities were lesser in AM than in CM. Milk pH was greater in AM than in CM. Milk Na, K, Na/K ratio, and Cl did not differ across the whole lactation. Milk pH had a positive correlation with milk Pl activity (r = 0.41), Na (r = 0.37), and Cl (r = 0.40) concentration, and negative correlation with the log(10) of pl/Pl ratio (r = -0.47). The milk Na/K ratio had a positive correlation (r = 0.55) with milk Pl activity. Milking system (MS) did not seem to affect mammary epithelial permeability. The differences in enzymatic (proteolytic) activity due to the MS, probably related to daily MF, lead one to suppose that the quality of the protein fraction for the cheese-making process was preserved better with AM than with CM, even if differences in pH might negatively interfere. No difference was detected in BCS, and in plasma concentration of triglycerides and nonesterified fatty acids, whereas plasma cholesterol concentration during the first 10 WOL was lesser in AM than CM. Oxidative status, measured by plasma reactive oxygen metabolites and thiol groups, did not differ between MS throughout the whole lactation. These results suggest that early lactation of AM primiparous cows may give rise to crucial situations: for milk production, when a low MF may impair further mammary cell proliferation; for milk quality, if an irregular MF, with prolonged milking intervals, leads to an increased milk pH with increased conversion of pl to Pl.

Automation in dairy cattle milking: experimental results and considerations

Abstract The results of two experimental programs financed to the Istituto Sperimentale per la Zootecnia are presented. The objective of the two Italian programs was the verify if automatic milking is a suitable practice for Italian dairy system. Results are summarised and compared to those obtained in other international projects. Results refer to animal behaviour, milk yield, milk quality an animal welfare. In a trial comparing cows milked with an automatic milking system and cows milked in a milking parlour, we observed that when the temperature and humidity are very high cows reduce their activity, have lower milking frequency and milk yield than in cold seasons. In comparison to milking parlour, automatic milking system did not increase milk yield which was affected significantly by season, stage of lactation, parity, season per treatment and parity per treatment. The causes of the negative results obtained by this group and by other international groups are discussed. We also presented the results obtained in four trials thereby four appetizers or flavourings were tested to improve efficiency of automatic milking system. Comparing the two milking systems, automatic milking determined a worsening of milk quality, but from these data is not possible to exclude the possibility to use automatic milking for Grana Padano and Parmigiano Reggiano-type cheeses. Animal welfare is not negatively influenced by automatic milking system, which has the potentiality to improve the control and care of cows.

Plasma estrone sulfate, clinical biochemistry, and milk yield of dairy cows carrying a fetus from a bull or its clone.

The aim of this article was to compare plasma estrone sulfate (E1SO4), clinical biochemistry, and milk yield of dairy cows carrying a female fetus from a bull (BULL) or from its clone (CLONE), evaluating also the relationship between the former variables and the birth weight of the newborn. Sixteen recipient dairy Friesian heifers (10 BULL and 7 CLONE) received a female embryo, obtained by in vitro embryo production and sexing by polymerase chain reaction with the semen of the BULL or the CLONE. Blood samples on all cows were obtained before feed distribution in the morning from jugular vein from 4 weeks before to 4 weeks after calving, to be analyzed for metabolic profile. The samples from late gestation were also analyzed for E1SO4 concentration. To separately assess the effect of calf birth weight (CBW), data were categorized as follows: low (<39 kg; BWT-A), mid (39-46 kg; BWT-B), and high (>46 kg; BWT-C). The plasma concentrations of β-hydroxybutyric acid (BHB, P=0.019), Na (P=0.002), Cl (P=0.026), strong cation-anion balance (P=0.020), total bilirubin (P=0.054), and α1-globulin (P=0.044) were higher in prepartum BULL recipients than those in CLONE, whereas BHB (P=0.021) and Mg (P=0.090) were higher in postpartum BULL recipients, while no differences were recorded in the remaining postpartum parameters. The CBW class had significant interaction with week of gestation on antepartum plasma estrone sulfate (P=0.021), whereas CBW per se affected antepartum plasma BHB (P=0.021), and nonesterified fatty acids (NEFA; P=0.011) being higher in BWT-C which also had the lower NEFA concentration during postpartum. Milk yield was unaffected by the sire used, both for quantitative and qualitative aspects. Cows carrying heavier fetus (BWT-C) had a different lactation affected by month compared with the other 2 CBW groups. From these results, there were no differences between BULL and CLONE recipients. Estrone sulfate, BHB, and NEFA may be used to predict CBW and provide different nutritional management during gestation.