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Characterization of new technological and nutritional properties of milk from cows of 6 breeds reared in multi-breed herds
Full text linkImproved animal production, largely as a result of genetic selection, was one of the greatest achievements of the last century. The dominant dairy cattle breed, at a global level, is the Holstein-Friesian. The breed has undergone an extreme genetic selection for several decades, towards high milk yield, and incorporated by high-nutrient and milk output systems. However, the high genetic pressure on only one trait, i.e. milk yield, resulted in unfavorable impacts on the welfare of the cows (i.e., metabolic stress, lameness, mastitis, reduced fertility and longevity). Moreover, as animals tend to adapt to the environment they are selected in, it is likely that selection for increased yield may also lead to environmental sensitivity. For instance, the negative correlation between production and fitness traits in less favorable environments is indicative of a decline in adaptability in the modern dairy cows. An increased importance exists, nowadays, for farm animal welfare that is recognized by all stakeholders in the farm animal production chain.
These considerations, together with the unchanged primary goal of the dairy industry for high milk quality for the consumer’s market, has lead, in some cases, in the use of crossbreeding between Holstein-Friesian and other dairy and dual-purpose breeds. In some countries, dual-purpose breeds such as the Simmental, Montbéliarde, Normande, and specialized breeds such as the Brown Swiss and Jersey are considered the breeds of choice for crossbreeding. These breeds, including the local Italian (North-east Italy) breeds of Rendena and Alpine Grey, tend to offer superior milk quality, complemented by high beefing merits. This combination can result in increased revenue from male calves and cull cow sales.
Nevertheless, comparison of milk quality of these different breeds is lacking in the literature, especially due to practical difficulties in the recording system of lots of animals, that are reared in different mixed-breed farms. To alleviate this problem, the Cowplus project has been developed at the Department of Agronomy, Food, Natural resources, Animals and Environment at University of Padova. The project permitted the sampling of 1,508 cows reared in 41 multi-breed herds, located in Trentino region in the north-eastern Italian Alps. Farms were selected from a pool of 610 herds enrolled in the Italian milk recording system. Cows were recorded for body characteristics, daily milk yield and composition, renneting aptitude, and cheese-yield. In total, 6 dairy and dual-purpose breeds were used. As part of the Cowplus project, this study aimed in: 1) the quantification and characterization of the effects of high or low herd productivity (defined according to the milk net energy yielded daily by the cows); 2) quantifying the variability of the herds within herd productivity class; 3) performing a within-herd comparison between the 3 dairy and the 3 dual-purpose breeds; 4) analyzing the effects of the days in milk (DIM) and the parity of the cows, on traditional milk quality and milk renneting aptitude (Chapter 1), cheese-making ability (Chapter 2), milk mineral elements (Chapter 3), and productivity and efficiency indicators of lactating cows (Chapter 4).
More precisely, the goal of the first chapter was to test the afore mentioned effects on coagulation properties, and assess the repeatability and reproducibility of traditional milk coagulation properties (MCP) and curd-firming over time (CFt) modeled and derived traits. Milk samples were collected from all the 1,508 cows and analyzed in duplicates (3,016 tests) using two lactodynamographs (Formagraph, FOSS) to obtain 240 curd-firmness (CF) measurements in 60 min (one every 15 sec) for each duplicate. Results showed that the effect of herd-date on the traditional and modeled MCP was modest while individual animal variance showed the highest incidence. The repeatability of MCP was high (> 80%) for all traits excluding those depending on the last part of the lactodynamographic curve (57 to 71%). The reproducibility, taking also into account the effect of instrument, was equal or slightly lower than repeatability. Milk samples collected in farms characterized by high level of productivity exhibited delayed coagulation but greater potential curd firmness compared to milk samples collected from low productivity herds. Large differences in all MCP traits were observed among breeds, both between specialized and dual-purpose breeds, and within the two groups, even after adjusting for milk quality and yield. Milk samples from Jersey cows, both for milk quality and MCP, and also from Rendena cows (but only for coagulation time) were superior respect to milk from Holstein-Friesian cows, while intermediate results were found for the other breeds of Alpine origin.
The second chapter aimed at evaluating the same effects on 508 model cheeses derived from 508 cows of 6 different breeds. For each cow 6 milk composition traits, 4 recovery traits (REC) of milk nutrients (fat, protein, solids and energy) in the curd, and 3 actual % cheese yield traits (%CY), expressing the fresh cheese, cheese solids and cheese water as percentages of the processed milk were analyzed (these traits were obtained during the experimental cheese-making process). In addition, 2 theoretical %CYs (fresh cheese and cheese solids) were calculated from the milk composition, and 2 overall cheese-making efficiencies (fresh cheese and cheese solids) were calculated as the % ratio between actual and theoretical %CYs. Daily milk yield (dMY) was also measured and estimates were made of 3 actual daily cheese yield production traits (dCY) per cow (fresh cheese, cheese solids and water retained in the cheese). Results showed that cows reared in high productivity herds yielded more milk with greater nutrient contents and more cheese per day, and had greater theoretical %CY, although to a lesser extent, actual %CY. However, they did not differ from low productivity herds in terms of REC traits (except solids), while they had a lower solid cheese-making efficiency. Individual herds within productivity classes were an intermediate source of total variation with respect to REC traits (11.3% to 17.1%), and to actual and theoretical %CY and estimates of efficiency (10.0% to 17.2%), and a major source for milk yield and dCY traits (43.1% to 46.3%). Breed within herd greatly affected all traits. Compared with the dual-purpose breeds, the 3 specialized dairy breeds (Holstein, Brown Swiss and Jersey) had, on average, a similar dMY, better milk composition, greater actual and theoretical %CY, similar fat and protein REC, and slightly lower cheese-making efficiency. Of the specialized dairy cow breeds, Holsteins produced more milk, but Brown Swiss cows produced milk with a greater nutrient content, greater nutrient REC, higher actual and theoretical %CY and a higher cheese-making efficiency, so the two large breeds had the same dCY. Small Jersey cows produced much less milk, with much more fat and protein and greater REC traits than the two large-framed breeds resulting in greater actual and theoretical %CY but similar efficiencies. Although the Jersey breed had lower dMY and dCY, the difference was much smaller for the latter. The differences among Simmental and the local Rendena and Alpine Grey were not very large. Compared with medium-framed cows of the local breeds, Simmentals had greater dMY, tended to have better milk composition, REC and %CY traits (but similar efficiencies), and also had much greater dCY. Among the local breeds, the higher dMY of Rendena was offset by the greater nutrient content of milk from the Alpine Greys, so their dCY was similar.
The objective of the third chapter was to test the same previous effects on 240 milk samples from 240 cows of 6 different breeds. Fifteen minerals were determined by Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). Results revealed that the effect of herd-date was large especially on environmental minerals (from 47 to 91% of the total variance), while it ranged from 11% to 61% considering both macro- and micro-minerals. Milk samples collected in farms characterized by high level of productivity exhibited richer mineral profile compared to milk samples collected from low productivity herds. Parity influenced exclusively macro-minerals, with the exception of Ca and S, while DIM influenced almost all minerals, with few exception related to the environmental elements. Large differences were observed among breeds, both between specialized and dual-purpose breeds, even after adjusting for milk quality and yield. Milk samples from Jersey and Brown Swiss cows were superior respect to milk from Holstein-Friesian cows, both for milk quality and mineral profile, while intermediate results were found for the other breeds of Alpine origin. Moreover, the variance of individual animals was much greater than variance of individual herds within herd productivity class.
The fourth chapter focused on the concepts of production, productivity and efficiency. As breed of cows and herd characteristics are the most important factors affecting milk productivity and efficiency, the aim of this chapter was to obtain independent evaluation of these factors on the data (body size and production) and milk characteristics from the 41 multi-breed herds on all 1,508 lactating cows from the 6 breeds. Nine productivity indicators and two simplified indicators of cow efficiency for cheese production, one energetic and one economic, were calculated. Results showed that breed within herd greatly affected all traits. On average the 3 dairy breeds were not much different from the 3 dual-purpose breeds, but large differences characterized both groups of cows. Jersey cows were the less productive, but, after correcting for herds effect and scaling for body size, they showed the highest efficiency among the dairy breeds. Holstein was the most productive dairy breed, but Brown Swiss cows had better milk quality and more efficient cheese-making aptitude and thus produced more cheese per day than Holsteins. Dual-purpose breeds were less variable than dairy ones, with Simmental with larger body size and production, but not productivity and efficiency respect to local Rendena and Alpine Grey breeds. If on one hand within herd comparison and correctly scaling of production traits reduced strongly herd differences in productivity, on the other hand they did not reduce very much the differences in terms of milk composition, technological properties and efficiency of cheese-making (recovery of milk nutrients in cheese), so that the differences among breeds remained strong and their importance on the overall efficiency evaluation of the breeds increased
The 9-MilCA method as a rapid, partly automated protocol for simultaneously recording milk coagulation, curd firming, syneresis, cheese yield, and curd nutrients recovery or whey loss
No full textThe aim of this study was to propose and test a new laboratory cheesemaking procedure [9-mL milk cheesemaking assessment (9-MilCA)], which records 15 traits related to milk coagulation, curd firming, syneresis, cheese yield, and curd nutrients recovery or whey loss. This procedure involves instruments found in many laboratories (i.e., heaters and lacto-dynamographs), with an easy modification of the sample rack for the insertion of 10-mL glass tubes. Four trials were carried out to test the 9-MilCA procedure. The first trial compared 8 coagulation and curd firming traits obtained using regular or modified sample racks to process milk samples from 60 cows belonging to 5 breeds and 3 farms (480 tests). The obtained patterns exhibited significant but irrelevant between-procedure differences, with better repeatability seen for 9-MilCA. The second trial tested the reproducibility and repeatability of the 7 cheesemaking traits obtained using the 9-MilCA procedure on individual samples from 60 cows tested in duplicate in 2 instruments (232 tests). The method yielded very repeatable outcomes for all 7 tested cheese yield and nutrient recovery traits (repeatability >98%), with the exception of the fresh cheese yield (84%), which was affected by the lower repeatability (67%) of the water retained in the curd. In the third trial (96 tests), we found that using centrifugation in place of curd cooking and draining (as adopted in several published studies) reduced the efficiency of whey separation, overestimated all traits, and worsened the repeatability. The fourth trial compared 9-MilCA with a more complex model cheese-manufacturing process that mimics industry practices, using 1,500-mL milk samples (72 cows, 216 tests). The average results obtained from 9-MilCA were similar to those obtained from the model cheeses, with between-method correlations ranging from 78 to 99%, except for the water retained in the curd (r = 54%). Our results indicate that new 9-MilCA method is a powerful research tool that allows the rapid, inexpensive, and partly automated analysis processing 40 samples per day with 2 replicates each, using 1 lacto-dynamograph, 2 heaters, and 3 modified sample racks, and yields a complete picture of the cheesemaking process (e.g., milk gelation, curd firming, syneresis, and whey expulsion) as well as the cheese yield and the efficiency of energy or nutrients retention in the cheese or loss in the whey
Effect of composition on coagulation, curd firming, and syneresis of goat milk
No full textThe present study investigated the effect of different levels of fat, protein, and casein on (1) traditional milk coagulation properties, and (2) curd firming over time parameters of 1,272 goat milk samples. Relationships between fat, protein, and casein and some indicators of udder health status (lactose, pH, somatic cells, bacterial count, and NaCl) were also investigated. Traditional milk coagulation properties and modeled curd-firming parameters were analyzed using a mixed model that considered the effect of days in milk, parity, farm, breed, the pendulum of the instrument, and different levels of fat, protein, and casein. Fat, protein, and casein were also tested with the same model but one at a time. Information provided by this model demonstrated the effect of one component alone, without contemporarily considering that of the others. The results allowed us to clarify the effect of the major milk nutrients on coagulation, curd firming, and syneresis ability of goat milk. In particular, milk rich in fat was associated with better coagulation properties, whereas milk rich in protein was associated with delayed coagulation. The high correlation of fat with protein and casein contents suggests that the effect of fat on the cheese-making process is also attributable to the effects of protein and casein. When only protein or only casein was included in the statistical model, the pattern of coagulation, curd firming, and syneresis was almost indistinguishable. The contemporary inclusion of protein and casein in the statistical model did not generate computing problems and allowed us to better characterize the role of protein and casein. Consequently, given their strong association, we also tested the effect of casein-to-protein ratio (i.e., casein number). Higher values of casein number led to a general improvement in the coagulation ability of milk, suggesting that casein-to-protein ratio, not just protein or casein, should be considered when milk is destined for cheese making. These results are especially useful for dairy farmers who want to increase their profits by improving the technological quality of the milk produced
Variation in caprine milk composition and coagulation as affected by udder health indicators
No full textAvailable and missing information on production factors in Parmigiano Reggiano area dairy farms
No full textA survey was conducted on 59 farms in the Parmigiano Reggiano cheese production area to understand the awareness
level of breeders on the availability and use of production factors in their farms. An interview including questions
on animal capital, productivity and management, feedstuff inventory and origin, animal nutrition and rations per
animal category, facilities and structures characteristics, land management and use, mechanical equipment and work
allocation was submitted to the breeders. Almost all breeders knew the number of animals per category in their farm
and, for the lactating cows, milk production and quality were well known on a herd basis. The 91.5% of the breeders
knew the average age at 1st calving whereas the number of calves weaned for reproduction (84.7%) or sold for
meat production (52.5%) were less known. The 92.2% of farmers was able to estimate the amount and origin of the
feedstuffs available in the farm, but only 44.1% of them was aware of the exact formula of the feedstuffs supplied to
the different categories of animals. Buildings size and stoking capacity data were available for the 70.8% of the cases
and a similar proportion of breeders (69.5%) was able to provide information about land usage and crops productivity. A
complete mechanical equipment list was provided in the 79.7% of the cases while the 55.9% of the breeders were able
to provide an estimation of labour allocation in animal activities. Results show that a sensible proportion of farmers
are missing key data related to herd management, nutrition, facilities and crops productivity; moreover, an accurate
traceability of work allocation is unavailable in a large number of dairy enterprises. Lacking of those information can
have detrimental effects on their efficiency and profitability. This project has received funding from the European
Union’s Horizon 2020 research and innovation programme, under the grant agreement No 777974
Effect of goat milk composition on cheesemaking traits and daily cheese production
No full textCheese yield is strongly influenced by the composi- tion of milk, especially fat and protein contents, and by the efficiency of the recovery of each milk component in the curd. The real effect of milk composition on cheesemaking ability of goat milk is still unknown. The aims of this study were to quantify the effects of milk composition; namely, fat, protein, and casein contents, on milk nutrient recovery in the curd, cheese yield, and average daily yield. Individual milk samples were col- lected from 560 goats of 6 different breeds. Each sample was analyzed in duplicate using the 9-laboratory milk cheesemaking assessment, a laboratory method that mimicked cheesemaking procedures, with milk heat- ing, rennet addition, coagulation, curd cutting, and draining. Data were submitted to statistical analysis; results showed that the increase of milk fat content was associated with a large improvement of cheese yield because of the higher recovery of all milk nutrients in the curd, and thus a higher individual daily cheese yield. The increase of milk protein content affected the recovery of fat, total solids, and energy in the curd. Casein number, calculated as casein-to-protein ratio, did not affect protein recovery but strongly influenced the recovery of fat, showing a curvilinear pattern and the most favorable data for the intermediate values of casein number. In conclusion, increased fat and protein contents in the milk had an effect on cheese yield not only for the greater quantity of nutrients available but also for the improved efficiency of the recovery in the curd of all nutrients. These results are useful to improve knowledge on cheesemaking processes in the caprine dairy industry
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Genetic Diversity in the Italian Holstein Dairy Cattle Based on Pedigree and SNP Data Prior and After Genomic Selection
Full text linkGenetic diversity has become an urgent matter not only in small local breeds but also in more specialized ones. While the use of genomic data in livestock breeding programs increased genetic gain, there is increasing evidence that this benefit may be counterbalanced by the potential loss of genetic variability. Thus, in this study, we aimed to investigate the genetic diversity in the Italian Holstein dairy cattle using pedigree and genomic data from cows born between 2002 and 2020. We estimated variation in inbreeding, effective population size, and generation interval and compared those aspects prior to and after the introduction of genomic selection in the breed. The dataset contained 84,443 single-nucleotide polymorphisms (SNPs), and 74,485 cows were analyzed. Pedigree depth based on complete generation equivalent was equal to 10.67. A run of homozygosity (ROH) analysis was adopted to estimate SNP-based inbreeding (FROH). The average pedigree inbreeding was 0.07, while the average FROH was more than double, being equal to 0.17. The pattern of the effective population size based on pedigree and SNP data was similar although different in scale, with a constant decrease within the last five generations. The overall inbreeding rate (ΔF) per year was equal to +0.27% and +0.44% for Fped and FROH throughout the studied period, which corresponded to about +1.35% and +2.2% per generation, respectively. A significant increase in the ΔF was found since the introduction of genomic selection in the breed. This study in the Italian Holstein dairy cattle showed the importance of controlling the loss of genetic diversity to ensure the long-term sustainability of this breed, as well as to guarantee future market demands
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