scholarly journals EFICÁCIA DA ESPECTROSCOPIA POR ULTRASSOM E DO CONGELAMENTO NA AVALIAÇÃO DA COMPOSIÇÃO QUÍMICA DO LEITE

Nativa ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 145
Author(s):  
Maura Frare Menegon ◽  
Claudineli Cassia Bueno da Rosa ◽  
Carmen Wobeto ◽  
Marcia Rodrigues Carvalho Oliveira ◽  
Henrique Melo da Silva ◽  
...  

Objetivou-se avaliar o método de espectroscopia por ultrassom (EU) e o efeito do congelamento do leite nas análises de gordura e proteína do leite de vaca. Cem amostras foram analisadas imediatamente após a coleta em tanque de expansão (in natura), congeladas a -20ºC por 30 dias e novamente analisadas por métodos oficiais (gordura por butirômetro de Gerber e proteína por micro-Kjeldahl) e por EU. Observou-se efeito de interação (P < 0,01) entre o método analítico e congelamento do leite. A EU superestimou (P < 0,01) o teor de gordura e subestimou (P < 0,01) o teor de proteína no leite in natura ou congelado. O congelamento não afetou (P = 0,15) o teor de gordura obtido pelo método oficial, mas reduziu o teor de gordura (P < 0,01) obtido com a EU. O congelamento aumentou (P < 0,01) o teor de proteína obtido pelo método oficial, mas reduziu (P < 0,01) quando obtido por EU. Os teores de gordura e proteína do leite obtidos pelo método de EU são divergentes daqueles obtidos por métodos oficiais, independente da amostra ser in natura ou congelada.Palavras-chave: método analítico; análise química; correlação. EFFICACY OF ULTRASONIC SPECTROSCOPY AND FREEZING IN EVALUATION OF MILK CHEMICAL COMPOSITION ABSTRACT: The objective was to evaluate the ultrasound spectroscopy (US) method and the effect of milk freezing on the cow's milk fat and protein analysis. One hundred samples were collected from one milk tank, immediately analyzed, and frozen at -20ºC for 30 days and analyzed again by official method (fat: Gerber butyrometer, protein: micro-Kjeldahl) and US. It was observed effect of interaction (P < 0.01) between analytical method and milk freezing. Ultrasound spectroscopy overestimated milk fat content and underestimated milk protein content on in natura or frozen. The milk freezing for 30 days did not affect the milk fat content obtained by official method (P = 0.15), but it reduced the milk fat content (P < 0.01) obtained by US. The milk freezing increased (P < 0.01) the milk protein content obtained by official method, but reduced (P <0.01) when obtained from US. The milk fat and protein content obtained by US are different from those obtained by official methods, regardless of the sample is in natura or frozen.Keywords: analytical method; chemical analysis; correlation.

Author(s):  
Martin Skýpala ◽  
Gustav Chládek

Milk yield varies during lactation, following what is termed a lactation curve. ŽIŽLAVSKÝ and MIKŠÍK (1988) recorded changes in milk yield within a day, too. TEPLÝ et al. (1979) a KOUŘIMSKÁ et al. (2007) published variation within a day ± 1.10 kg in milk yield, ± 0.75 % in milk fat content and ± 0.20 % in milk protein content. Milk yield of cows can be expressed in many different ways, for instance, in kilograms per lactation or in kilograms per day. A practical parameter describing milk production is milk yield (kg) per milking.The object of experiment were 12 cows of Holstein cattle on the first lactation from the 100-day of lactation to 200-day of lactation. The samples of milk were collected from January to May 2007, once a month from the morning and evening milking (milking interval 12 h ± 15 min.). The following parameters were monitored: milk production – milk yield (kg), milk protein production (kg), milk fat production (kg); milk composition – milk protein content (%), milk fat content (%), lactose content (%), milk solids-not-fat content (%), milk total solids content (%); technological properties of milk – ti­tra­tab­le acidity (SH), active acidity (pH), rennet coagulation time (s), quality of curd (class) and somatic cell count as a parameter of udder health.Highly significant differences were found (P < 0.01) between morning milk yield (15.7 kg) and evening milk yield (13.8 kg), between morning milk protein production (0.51 kg) and evening milk protein production (0.45 kg) and between evening milk fat content (4.41 %) and morning milk fat content (3.95 %). A significant difference (P < 0.05) was found between morning milk total solids content (12.62 %) and evening milk total solids content (12.07 %). No significant differences were found between morning (M) and evening (E) values of the remaining parameters: milk fat production (M 0.62 kg; E 0.60 kg), milk protein content (M 3.24 %; E 3.27 %), milk lactose content (M 4.78 %; E 4.86 %), milk solids-not-fat content (M 7.69 %; E 7.71 %), somatic cell count (M 80 000/1 mL; E 101 000/1 mL), titratable aci­di­ty (M 7.75 SH; E 7.64 SH), active acidity (M pH 6.58; E pH 6.61), rennet coagulation time (M 189 s.; E 191 s.), quality of curd (M 1.60 class; E 1.57 class).


1999 ◽  
Vol 66 (2) ◽  
pp. 177-191 ◽  
Author(s):  
RAMON CASALS ◽  
GERARDO CAJA ◽  
XAVIER SUCH ◽  
CELINA TORRE ◽  
SERGIO CALSAMIGLIA

Forty-eight Manchega dairy ewes were used during a complete lactation in a 2×2 factorial design to determine the effects of supplementing diets with fat (calcium soaps of palm oil fatty acids, CSFA) and rumen undegradable protein (RUP) on milk production and composition. Factors tested were amounts of CSFA (0 or 200 g/kg) and RUP (300 or 450 g/kg crude protein) in the concentrate. RUP was altered by adding a mixture of maize gluten meal and blood meal. Lactation was divided into one nursing period (period 1, weeks 1–4), and three milking periods (periods 2–4, weeks 5–8, 9–14 and 15–21). Concentrates were given at 0–8 kg/d during periods 1 and 2, and at 0–6 kg/d in periods 3 and 4. Ewes grazed rotationally in an Italian rye-grass pasture and received a daily supplement of 0·8 kg vetch–oat hay during period 1, and 0·3 kg lucerne hay during periods 2–4. For the whole lactation, supplemental fat markedly increased milk fat content (+23%) and yield (+16%), and decreased milk protein content (−9%). The positive effect of feeding CSFA on milk fat content was more evident at the beginning of lactation; however, its negative effect on milk protein was more pronounced in late lactation. Supplementary RUP had little effect, increasing milk protein content only in period 3, when the crude protein content of pasture was lower. Milk yield and lamb growth were not affected by dietary treatments. The results indicated that CSFA can be useful for increasing the milk fat content of dairy ewes at pasture, which may help farmers to produce milk reaching the minimum requirements of fat content for the cheese industry.


Author(s):  
Gustav Chládek ◽  
Vladimír Čejna

The freezing point of milk (FPM) is an instant indicator of violated technological quality of raw milk, especially of dilution. FPM can also vary due to numerous effects associated with changes in milk composition and milk characteristics. Beside the effect of season, phase of lactation, breed, milk yield, sub-clinical mastitis etc. the impacts of nutrition and dietary or metabolic disorders are the most significant and the most frequent (GAJDŮŠEK, 2003). FPM is a relatively stable physical characteristic and due to osmotically active elements it ranges from – 0.510 to – 0.535 °C (HANUŠ et al., 2003b). Recently ŠUSTOVÁ (2001) studied the freezing point of milk in pool samples; she observed seasonal changes in FPM of mixed milk and the effect of different diets on FPM values. KOLOŠTA (2003) looked into the effect of grazing season on FPM. HANUŠ et al. (2003a) analysed possible effects of handling of milk components on FPM.The aim of this work was to describe the relationship between FPM and milk components and the impact of breed, number and phase of lactation on FPM. We analysed 328 milk samples in total, out of which 137 samples were of Czech Pied cows and 191 samples of Holstein cows. The effect of number and phase of lactation was evaluated for both breeds together. The greatest coefficients of correlation in total were found between FPM and lactose content (r = 0.600) and solids non fat (r = 0.523). Lower coefficients of correlation were found between FPM and milk fat content (r = 0.235), milk protein content (r = 0.260) and urea concentration (r = 0.256). These coefficients were considerably lower in Holstein cows than in Czech Pied cows. The coefficients of correlation between FPM and number and phase of lactation and somatic cells count were insignificant. The total mean value of FPM was – 0.534 °C. Breed statistically significantly (P<0.01) affected FPM (+0.006 °C in C breed) and milk fat content (+0.19 % in H breed). Breed highly significantly (P<0.001) affected daily milk yield (+4.9 kg milk in H), milk protein content (+0.27 % in C) and solids non fat (+0.37 % in C). On the contrary, breed had no significant effect on lactose content, urea concentration and somatic cells count.Variability of FPM was greater in Czech Pied cows (5.9 %) than in Holstein cows (0.9 %). Number of lactation had no significant effect on FPM (maximum difference between lactations was 0.008 °C). Phase of lactation had no significant effect on FPM either. Our study revealed the fact that FPM was most of all affected by lactose content and solids non fat. However, the decrease of lactose content was compensated by a tendency of mammary glad to keep constant osmotic pressure. As the somatic sells count was low, there was no decline in lactose content during later lactations so no significant decrease of FPM occurred.


2015 ◽  
Vol 67 (3) ◽  
pp. 927-934 ◽  
Author(s):  
G.A. Gagliostro ◽  
E.M. Patiño ◽  
M. Sanchez Negrette ◽  
G. Sager ◽  
L. Castelli ◽  
...  

The aim of the study was to examine the changes in milk fatty acid (FA) profile of grazing buffaloes fed either low (L, 276g/d) or high (H, 572g/d) doses of a blend (70:30, wt/wt) of soybean and linseed oils. Fourteen multiparous Mediterranean buffaloes grazing on a native pasture were fed 4 kg/day of a commercial concentrate containing no supplemental oil over a pre-experimental period of ten days. The baseline milk production and composition and milk FA profile were measured over the last three days. After this pre-experimental period the animals received the same concentrate added with either the L or H oil doses for 26 additional days. Milk yield (g/animal/day) did not differ at the start (1776 ± 522 and 1662 ± 291 for L and H, respectively, P<0.622) or at the end of the trial (4590 ± 991 and 4847 ± 447 in L and H, respectively, P<0.543). Baseline milk fat content (g/kg) averaged 77.1 (±20.5) in L and 74.3 (±9.9) in H (P<0.10) and was reduced (P<0.031) to 60.7 (±23.6) and 49.4 (±11.2) (P<0.0031) respectively after L and H with no differences between treatments (P<0.277). Baseline milk protein content (L=43.2 ± 3.4 and H= 44.3 ± 6.9g/kg) increased after oil supplementation (P<0.0001) in both L (73.2 ± 6.0g/kg) and H (68.4 ± 4.9g/kg) without differences between oil doses (P<0.123). Milk fat content of 14:0 decreased after oil supplementation only in the H treatment (5.29 to 4.03, P<0.007) whereas that of 16:0 was reduced (P<0.001) at both L (24.49 to 19.75g/100g FA) and H (25.92 to 19.17g/100g FA) doses. The reduction of total content of 12:0 to 16:0 was higher (P<0.052) in H (32.02 to 23.93g/100g FA) than L (30.17 to 25.45g/100g FA). Vaccenic acid content increased (P<0.001) from 5.70 to 13.24g/100g FA in L and from 5.25 to 16.77 in H, with higher results in the in H treatment (P<0.001). Baseline rumenic acid was sharply increased (P<0.001) in L (1.80 to 4.09g/100g FA, +127%) and H (1.60 to 4.61g/100g FA, +187%) with no differences between L and H (P<0.19). Overall, these results indicate a pronounced improvement in the nutritional value of milk fat from grazing buffaloes fed little amounts (0.276g/day) of a blend of soybean and linseed oils.


Author(s):  
A Gavelis ◽  
V. Þilaitis ◽  
A Juozaitis ◽  
V. Juozaitienë ◽  
G. Urbonavièius ◽  
...  

The aim of this study was to evaluate relationship between milk progesterone concentration (P4) and milk traits at the start of estrus time and 12h after start of the estrus in dairy cows. The 96 milk samples of 48 Lithuanian dairy cows without reproduction disorders and 90–100 days after calving were evaluated. Cows were classified into two groups based on milk yield per day: less than 30 kg (n=20) and e”30 kg (n=28). Data were categorized by milk fat and protein content at the start estrus and 12h after start of estrus to evaluate relationship between P4 and milk traits examined. P4 at estrus time in dairy cows was significantly positively correlated with milk yield (P less than 0.001), whereas it was negatively correlated with milk protein (P less than 0.05-P less than 0.01) and fat at 12h after start of estrus. Dairy cows with F/P from 1.0 to 1.5 had the lowest P4 in milk. Results of the pregnancy in dairy cows were related with lower P4 and milk yield level (P less than 0.001), higher milk fat (P less than 0.05) and milk protein content (P less than 0.001). These cows had 1.90 times lower prevalence of the signs of subclinical ketosis (P less than 0.05) at estrus time when compared with non-pregnant cows. As a result, it was clearly demonstrated that P4 in dairy cows can help to evaluate and improve the reproductive properties of cows.


2015 ◽  
Vol 31 (2) ◽  
pp. 245-253 ◽  
Author(s):  
N. Maksimovic ◽  
F. Bauman ◽  
M.P. Petrovic ◽  
V.C. Petrovic ◽  
D. Ruzic-Muslic ◽  
...  

The purpose of this study was to evaluate present level of productivity and determine linear body traits of Alpine goats raised in Serbia on smallholder farms. Data were collected from 22 smallholder farms located in Belgrade district, with total of 330 purebred Alpine does 2-9 years of age, 145 yearling does and 476 kids. Traits measured were: body weight of does, body weight of kids at birth, 30 days of age and at weaning (90-120 days), prolificacy of mature and yearling (primiparous) does, six linear body traits of does (wither height, body length, hearth girth, chest depth, chest width, pelvic width) and milk production (milk yield, milk fat and milk protein content). The analysis showed the average body weight of does to be 54.96 kg, while the average body weight of kids at birth, 30 days of age and weaning was 2.73 kg, 8.7 kg and 18.3 kg., respectively. Prolificacy was 144% in mature and 125% in yearling does. Measurements of linear body traits were: wither height 67.87 cm, body length 71.92 cm, hearth girth 81.79 cm, chest depth 32.93, chest width 21.49 cm and pelvic width 17.63 cm. Among dairy production traits, following results were obtained: lactation length 220.73 days, total milk yield 531.66 kg, milk fat content 3.33% and milk protein content 3.16%. It was concluded that the overall productivity of Alpine goats raised under smallholder production systems in Serbia is satisfying. Giving the fact that these animals are usually kept under poor conditions, many of these productive traits are very good.


2000 ◽  
Vol 25 ◽  
pp. 179-199 ◽  
Author(s):  
J.C. MacRae ◽  
B.J. Bequette ◽  
L.A. Crompton

AbstractDietary manipulation of milk fat content and/or fatty acid composition is becoming a feasible, and for certain niche–markets, attractive means of boosting the nutritive value and acceptability of milk and its secondary products. However it is not yet possible to indicate equivalent ways of manipulating milk protein content and/or composition. This paper will consider current knowledge on milk protein biosynthesis and the opportunities for nutritional manipulation. Recent infusion studies which have linked changes in mammary amino acid metabolism with changes in milk protein content will be examined in an attempt to elucidate key features of the metabolic regulation of the dairy cow which need to be addressed if the British consumer is to have the choice of higher protein (possibly designer protein) milk products. This review will (in part) utilise data from a joint project at the Rowett Institute and Reading University funded by a consortium comprising government (MAFF, BBSRC and SOAEFD) and agribusiness (MDC, Purina Mills and Hendrix).


1998 ◽  
Vol 1998 ◽  
pp. 201-201
Author(s):  
R. H. Phipps ◽  
A. K. Jones ◽  
J.G. Perrot

An earlier study conducted at the Centre for Dairy Research (Phipps et al. 1996) using a total mixed ration (TMR) based on maize silage, showed that when distillers grains wheat and molassed sugar beet feed (MSBF) replaced cereal and protein supplements, milk yield and dry matter (DM) intake were maintained but there was a large and significant reduction in milk fat and a small but significant reduction in milk protein. This depression in milk protein was attributed to the high oil content of distillers grains, which would have reduced fermentable metabolisable energy intake which in turn may have adversely affected microbial protein synthesis and reduced milk protein content. The aim of the current study was to devise a nutritional regime using distillers grains maize (DGM) and MSBF in a TMR which would allow milk fat content to be substantially reduced without compromising either DM intake, milk yield or milk protein content.


1998 ◽  
Vol 1998 ◽  
pp. 201-201
Author(s):  
R. H. Phipps ◽  
A. K. Jones ◽  
J.G. Perrot

An earlier study conducted at the Centre for Dairy Research (Phipps et al. 1996) using a total mixed ration (TMR) based on maize silage, showed that when distillers grains wheat and molassed sugar beet feed (MSBF) replaced cereal and protein supplements, milk yield and dry matter (DM) intake were maintained but there was a large and significant reduction in milk fat and a small but significant reduction in milk protein. This depression in milk protein was attributed to the high oil content of distillers grains, which would have reduced fermentable metabolisable energy intake which in turn may have adversely affected microbial protein synthesis and reduced milk protein content. The aim of the current study was to devise a nutritional regime using distillers grains maize (DGM) and MSBF in a TMR which would allow milk fat content to be substantially reduced without compromising either DM intake, milk yield or milk protein content.


Author(s):  
М.Ю. САННИКОВ ◽  
С.И. НОВОПАШИНА ◽  
С.А. ХАТАТАЕВ ◽  
Е.И. КИЗИЛОВА

Изучена молочная продуктивность потомства I, II и III поколений при скрещивании молочных коз в типе зааненской породы с козлами нубийской породы. Установлено, что самый высокий удой за лактацию (576,5±11,62) был у чистопородных зааненских коз (n=72) — на 10,8—25,3% (P≦0,05) больше, чем у помесных животных за счет более длительной лактации (на 13,0%). Среднесуточный удой за лактацию был на 2,1% выше у помесей I поколения (n=26), чем у зааненских, на 4,9% — чем у помесей II (n=24) и на 13,5% — чем у помесей III поколений (n=21) (P≦0,05). Козоматки III поколения по содержанию жира превосходили сверстниц на 0,14—0,50 абс. процента, а белка — на 0,18—0,37 абс. процента. Среднесуточное количество молочного жира было выше у помесей I поколения на 0,9—7,3%, молочного белка — на 1,5—5,1%. За счет более продолжительного периода лактации козоматки зааненской породы превосходили своих помесных сверстниц по количеству молочного жира на 5,3—11,8% (1,2—2,5 кг) и по количеству молочного белка — на 7,7—11,3% (1,2—1,7 кг). Таким образом, поглотительное скрещивание является эффективным приемом для получения чистопородных животных нубийской породы. И может быть использовано в качестве селекционного приема в товарных хозяйствах для повышения качественных показателей молока коз в типе зааненской породы. Milk productivity of the offspring of generations I, II, and III during milk goat breeding in the type of the Saanen breed with goats of the Nubian breed was studied. It was found that the highest milk yield per lactation (576.5±11.62) was demonstrated by purebred Saanen goats (n=72) — by 10.8—25.3% (P≦0.05) more than in crossbred animals due to prolonged lactation (by 13.0%). Average daily milk yield per lactation was 2.1% higher in crossbred animals of generation I (n=26) compared to the Saanen breed, 4.9% higher than in crossbred animals of generation II (n=24), and 13.5% higher than in crossbred animals of generation III (n-21) (P≦0.05). By fat content the breeding goats of generation III are superior to their age-mates by 0.14—0.50 absolute percent, and by protein — by 0.18—0.37 absolute percent. Average daily milk fat content was 0.9—7.3% higher in crossbred animals of generation I; average daily milk protein content was 1.5—5.1% higher. Due to prolonged lactation breeding goats of the Saanen breed were superior to their crossbred age-mates in milk fat quantity by 5.3—11.8% (1.2—2.5 kg), and in milk protein quantity — by 7.7—11.3% (1.2—1.7 kg). Accordingly, accumulation cross breeding is an effective method of obtaining purebred animals of the Nubian breed. It can be used as a selection technique in commercial farming to increase qualitative characteristics of goat milk in the type of the Saanen breed.


Sign in / Sign up

Export Citation Format

Share Document