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PubMed2002

Effect of frequency of milking on yield, composition and processing quality of milk.

The objective was to determine the effect of once-daily milking (ODM) and omitting one evening milking each week (13TWM), in late lactation on milk production, composition and processability. Seventy-two cows were assigned to three treatments (ODM, 13TWM and twice-daily milking [TDM]) from 4 October to 12 December. Cows were on average 218 d into lactation at the start of the trial, and all cows were managed similarly throughout the trial. Milk yields and gross milk composition of cows on all treatments were measured, and milk samples for detailed compositional and processability analysis were collected from TDM and ODM treatments at two consecutive milkings and at one milking each week, respectively. Milk yield was significantly reduced (P < 0.001) and milk fat and protein concentrations were increased (P < 0.01) with ODM compared with TDM. Milk yield and fat and protein concentrations of milk from TDM and 13TWM herds were similar. Casein concentrations in ODM and TDM milks were similar, but ODM milk had a higher (P < 0.05) whey protein content. Somatic cell count of ODM and TDM milks was similar. Rennet coagulation time (RCT) and curd firmness (A60) of milk were not affected by milking frequency. However, rate of curd aggregation (K20) of ODM milk was reduced (P < 0.05) compared with that of TDM milk. Plasmin activity in ODM milk was numerically higher than in TDM milk, but the effect was not significant. ODM milk had higher NAGase activity than TDM milk (P < 0.01). In conclusion, once daily milking reduced milk yield by 29% and did not adversely affect the processability of milk. Moreover, one evening milking per week could be eliminated without adverse effects on milk yield or composition.

Acetylglucosaminidase↗
PubMed2005

Milk quality and automatic milking: fat globule size, natural creaming, and lipolysis.

Thirty-eight Italian Friesian first-lactation cows were allocated to 2 groups to evaluate the effect of 1) an automatic milking system (AMS) vs. milking in a milking parlor (MP) on milk fat characteristics; and 2) milking interval (< or =480, 481 to 600, 601 to 720, and >720 min) on the same variables. Milk fat was analyzed for content (% vol/vol), natural creaming (% of fat), and free fatty acids (FFA, mEq/100 g of fat). Distribution of milk fat globule size was evaluated to calculate average fat globule diameter (d(1)), volume-surface average diameter (d(32)), specific globule surface area, and mean interglobular distance. Milk yield was recorded to calculate hourly milk and milk fat yield. Milking system had no effect on milk yield, milk fat content, and hourly milk fat yield. Milk from AMS had less natural creaming and more FFA content than milk from MP. Fat globule size, globular surface area, and interglobular distance were not affected by milking system per se. Afternoon MP milkings had more fat content and hourly milk fat yield than AMS milkings when milking interval was >480 min. Milk fat FFA content was greater in AMS milkings when milking interval was < or =480 min than in milkings from MP and from AMS when milking interval was >600 min. Milking interval did not affect fat globule size, expressed as d32. Results from this experiment indicate a limited effect of AMS per se on milk fat quality; a more important factor seems to be the increase in milking frequency, generally associated with AMS.

Animals↗
PubMedDate not supplied

Effect of suckling cow's milk or milk replacer on abomasal luminal pH in dairy calves.

Abomasal ulceration occurs commonly in suckling calves, and the cause for the high prevalence of abomasal ulceration is unknown. We hypothesized that diet may play a role in the etiopathogenesis of abomasal ulceration. Six male dairy calves with an abomasal body cannula suckled fresh Holstein cow's milk, all milk-protein milk replacer, or combined milk- and soy-protein milk replacer twice daily at 12% of body weight/d. Abomasal luminal pH was measured every second for 24 hours by using a miniature glass pH electrode. Mean 24-hour abomasal luminal pH for all milk-protein milk replacer (3.22) and combined milk- and soy-protein milk replacer (3.27) were similar but significantly (P < .05) higher than that for cow's milk (2.77; standard error = 0.08). Both milk-replacer formulations failed to clot after the addition of chymosin, whereas cow's milk clotted within 2 minutes. The in vitro titration curve of cow's milk and all milk-protein milk replacer were similar, but different to that of combined milk- and soy-protein milk replacer. The osmolalities of all milk-protein milk replacer (375 mOsm/kg) and combined milk- and soy-protein milk replacer (410 mOsm/kg) were greater than that of cow's milk (278 mOsm/kg). The slightly lower mean abomasal luminal pH in calves suckling cow's milk, compared to milk replacer, was probably due to clotting of cow's milk, with extrusion of low pH whey, and a slower rate of abomasal emptying caused by the hyperosmolality of milk replacer. Examination of our results suggests that suckling cow's milk may increase the prevalence of abomasal ulceration by decreasing mean luminal pH, although this remains to be determined.

Abomasum↗
PubMed2002

Estimating daily fat yield from a single milking on test day for herds with a robotic milking system.

The objective of this study was to estimate the daily fat yield and fat percentage from one sampled milking per cow per test day in an automatic milking system herd, when the milking times and milk yields of all individual milkings are recorded by the automatic milking system. Multiple regression models were used to estimate the 24-h fat percentage when only one milking is sampled for components and milk yields and milking times are known for all milkings in the 24-h period before the sampled milking. In total, 10,697 cow test day records, from 595 herd tests at 91 Dutch herds milked with an automatic milking system, were used. The best model to predict 24-h fat percentage included fat percentage, protein percentage, milk yield and milking interval of the sampled milking, milk yield, and milking interval of the preceding milking, and the interaction between milking interval and the ratio of fat and protein percentage of the sampled milking. This model gave a standard deviation of the prediction error (SE) for 24-h fat percentage of 0.321 and a correlation between the predicted and actual 24-h fat percentage of 0.910. For the 24-h fat yield, we found SE = 90 g and correlation = 0.967. This precision is slightly better than that of present a.m.-p.m. testing schemes. Extra attention must be paid to correctly matching the sample jars and the milkings. Furthermore, milkings with an interval of less than 4 h must be excluded from sampling as well as milkings that are interrupted or that follow an interrupted milking. Under these restrictions (correct matching, interval of at least 4 h, and no interrupted milking), one sampled milking suffices to get a satisfactory estimate for the test-day fat yield.

Animals↗
PubMed2004

Effect of different milking intervals on the composition of cisternal and alveolar milk in dairy cows.

Effects of six different milking intervals on the distribution of milk between cistern and alveoli were studied in a randomized, incomplete Latin Square experiment with four lactating Holstein cows. Cisternal and alveolar milk was measured by udder quarter at 4, 8, 12, 16, 20 and 24-h intervals with a 3-d interperiod of regular milking. Cisternal milk was evacuated using a cannula after injection of an oxytocin-receptor blocking agent, followed by an injection of oxytocin to remove the alveolar fraction. Milk samples from each fraction and quarter were collected for analysis. Cisternal and alveolar milk increased with milking interval and represented on average 30 and 70% of the milk stored in the udder, respectively. Fat content in alveolar milk remained constant during the first 16 h, increasing rapidly thereafter, reaching its maximum at 24 h (6.95%). Fat content in cisternal milk decreased with milking interval and reached its minimum at 24 h (0.96%). Total fat yield tended to increase for cisternal milk with longer milking intervals, but it increased markedly for alveolar milk, showing that fat globules did not pass freely from alveoli to cistern between milkings. Milk protein content was greater in rear quarters than in front quarters for both milk fractions. Milk protein content increased in the cisternal milk fraction and tended to increase in the alveolar milk fraction with longer milking intervals, but values did not differ between cisternal and alveolar fractions or between front and rear quarters. Total protein yield increased with milking interval in both fractions, indicating that casein micelles passed more freely than fat globules from the alveolar to the cisternal compartment. In conclusion, the short-term effects of milking intervals in milk composition were explained by the changes observed in alveolar and cisternal milk ratio.

Animals↗
PubMed2001

Implication of milk and milk products in food-borne diseases in France and in different industrialised countries.

A study was carried out to estimate the proportion of diseases due to milk and milk products among food-borne diseases recorded in France and in other countries since 1980. Particular attention was given to whether the milk involved was heat-treated or not. Four etiologic agents were considered: Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and pathogenic Escherichia coli. An overview of food-borne disease annual reports from seven countries indicated that milk and milk products were implicated in 1-5% of the total bacterial outbreaks; however, details about the type of product and milk involved were usually not provided. When considering 60 outbreaks and four single cases described in the literature and implicating milk and milk products, confirmed or suspected food vehicles were distributed as follows: milk, 39.1%, cheese, 53.1%, other milk products, 7.8%. Overall, 32.8% of the food vehicles were made from pasteurised milk; 37.5% from raw milk; 10.9% from milk stated as "unpasteurised"; and 18.8% from unspecified milk. Salmonella spp. were responsible for 29 outbreaks, L. monocytogenes for 10 outbreaks and four well-documented single cases, pathogenic E. coli for 11 outbreaks, and S. aureus for 10 outbreaks. Analysis of unpublished data about food-borne disease outbreaks, listeriosis excluded, collected by the coordinator of the French surveillance system from 1992 to 1997, revealed 69 documented outbreaks for which milk and milk products were confirmed as the vehicle by the isolation of the etiologic agent. The food vehicles were distributed as follows: milk, 10%; cheese, 87%; others, 3%. UHT milk accounted for 1.5%, raw milk and raw milk products for 48%, and milk and milk products from unspecified milk for 50.5% of the 69 outbreaks. S. aureus was by far the most frequent pathogen associated with these outbreaks (85.5% of the outbreaks), followed by Salmonella (10.1%). This study demonstrates the limitations of the surveillance systems and the difficulties in estimating the contribution of milk and milk products to food-borne diseases. In particular, it was not possible to find out in many outbreaks what heat treatment, if any, the milk had undergone.

Animals↗
PubMed2003

A comparison of selected public health criteria in milk from milk-shops and from a national distributor.

Selected public health criteria of pasteurised milk available to the consumer from milk-shops in a pre-defined area of Pretoria compared with a national distributor's milk was evaluated. Of the 135 milk samples purchased from milk-shops, 87% were not fit for human consumption on the basis of the minimum standards prescribed in the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of1972). The national distributor's milk (n = 79) did not contain any pathogens, toxins nor inhibitory substances and passed all the criteria laid down in the Act. Even though milk-shop milk was sold as having been pasteurised, 38.5% of samples were alkaline phosphatase positive, indicating probable inadequate pasteurisation. Milk-shop milk quality varied between milk-shops and between sampling days and differed significantly (P < 0.05) from the national distributor's milk. Total aerobic plate and coliform counts were generally high for all milk-shop milk samples. Somatic cell counts of milk-shop milk differed significantly (P < 0.05) from the national distributor's milk. Escherichia coli was detected in 1 ml of 17% of milk-shop milk, 95% of which originated from milk which was alkaline phosphatase positive. Salmonella spp. could not be detected in 1 ml in any of the E. coli-positive milk tested. Staphylococcus aureus was isolated from 40% of milk-shop milk samples, and S. aureus enterotoxins from 7.8% of 51 cultures. Inhibitory substances were detected in 54.1% of milk-shop milk. The presence of inhibitory substances and the isolation of E. coli and S. aureus (some of which were able to produce enterotoxins) indicated potentially unsafe milk and poses a serious public health risk to consumers.

Alkaline Phosphatase↗
PubMed2006

Absorption of calcium from milks enriched with fructo-oligosaccharides, caseinophosphopeptides, tricalcium phosphate, and milk solids.

BACKGROUND: Adequate intakes of calcium are required for optimal bone health and protection against chronic disease. Dairy products are an excellent source of calcium. OBJECTIVE: The absorption of calcium from a range of fortified milks was measured in humans with the use of stable isotopes. DESIGN: Fifteen volunteers participated in a randomized, controlled, double-blind crossover study. Five types of semi-skimmed (1.9% fat) milk drinks were administered with a light breakfast: standard milk (control milk); milk enriched with calcium from milk solids and tricalcium phosphate [(TCP) MSS milk]; milk enriched with calcium from concentrated milk (CON milk); milk with added fructo-oligosaccharides [(FOSs) FOS milk]; and milk with added caseinophosphopeptides [(CPPs) CPP milk]. All the milks were labeled with 42Ca as CaCl2. The MSS milk was also labeled with 44Ca as TCP. The quantity of calcium in each drink was kept the same by varying the volume given. RESULTS: Calcium absorption did not differ significantly between the control milk and the calcium-fortified milks (MSS and CON milk) or the FOS and CPP milks. However, calcium absorption from the TCP added to the MSS milk was significantly higher than that from the control milk (27.5 +/- 7.6% and 24.5 +/- 7.3%, respectively; P = 0.003). CONCLUSIONS: Calcium-enriched milks are a valuable source of well-absorbed calcium. Absorption of added calcium as TCP was higher than that of calcium from the control milk, but the addition of FOSs or CPPs did not significantly increase calcium absorption. Further research is needed to ascertain the cost-effectiveness and public health benefits of consuming fortified milks.

Adult↗
PubMed2001

Trace elements and their distribution in protein fractions of camel milk in comparison to other commonly consumed milks.

Studies on camels' milk, whether with respect to concentration or bioavailability of trace elements from this milk, are limited and warrant further investigation. The object of this study was to analyse the concentration and distribution of zinc, copper, selenium, manganese and iron in camel milk compared to those in human milk, cows' milk and infant formula under similar experimental conditions. Camels' milk and cows' milk were collected from local farms, human milk samples were obtained from healthy donors in Kuwait and infant formula was purchased locally. Milk fractionation was performed by ultra-centrifugation and gelcolumn chromatography. The concentration of trace elements was analysed by atomic absorption spectrometry and that of protein was determined spectrophotometrically. The concentration of manganese and iron in camels' milk was remarkably higher (7-20-fold and 4-10-fold, respectively) than in human milk, cows' milk and infant formula. The zinc content of camels' milk was higher than that of human milk but slightly lower than in cows' milk and infant formula. The concentration of copper in camels' milk was similar to that of cows' milk but lower than in human milk and infant formula. The selenium content of camels' milk was comparable to those of other types of milk, Approximately 50-80% of zinc, copper and manganese in camels' milk were associated with the casein fraction, similar to that of cows' milk, The majority of selenium and iron in camels' milk was in association with the low molecular weight fraction, It is recommended that camels' milk be considered as a potential source of manganese, selenium and iron, perhaps not only for infants, but also for other groups suspected of mild deficiency of these elements. Further investigations are required to confirm this proposal.

Animals↗
PubMed1993

Nutritional factors affecting milk quality, with special regard to milk protein: a review.

This paper reviews some of the recent scientific literature that relates nutritional management to protein concentration in the milk of dairy cows. Nutritional management of the dairy cattle was organized under the headings of nutrition and body condition before calving, forage to concentrate ratio, type and treatments of forage, dietary fibre, dietary protein, dietary amino acid supplementation, dietary fat, dietary carbohydrates, concentrate composition, vitamins, feed additives, and feeding frequency. The level of feeding and rate of liveweight change prior to calving within "normal" limits seems to have relatively little effect on milk yield and composition. Cows which are thin at calving, are biologically more efficient because they produce more milk directly from food rather than from mobilization of body reserves. Increasing the forage content of the diet leads to increased milk fat and depressed milk protein as well as milk yield, and vice versa. Modification of forage type and the treatments of forage seem to exert a relatively weak effect on milk composition. Increasing neutral detergent fibre (NDF) concentration of the diet from 25% to 37% on dry matter (DM) basis corresponds to a linear decrease in milk production, milk protein and a linear increase in the fat content of milk. When data were analysed by the source of roughage, a significant interaction of effects was found between NDF content of the diet on milk yield. Increasing the protein concentration of the diet up to 22% was found to raise milk yield and milk fat concentration, but an increase beyond that level had no consistent effect. A moderate amount of undegradable protein, however, can improve the milk yield and milk protein content of high-lactating cows. Milk protein concentration may be improved by various combinations of ruminally protected methionine and lysine if these amino acids are limiting in the diet. The inclusion of free lipids in diets generally increases the milk yield, but decreases milk protein concentration. By-pass lipids improve milk yield. Levels of dietary fat above 6-7 per cent lead to a depression of both total milk yields and fat and protein content. The source of carbohydrate in the concentrate has little effect on milk production when the concentrates are of similar metabolizable energy (ME) content. Dietary beta carotene has no significant effects on milk production or milk components, while vitamin A may be more effective. Niacin supplementation may correct a milk protein depression induced by dietary oil.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Feed↗
PubMed2001

Formula milk versus term human milk for feeding preterm or low birth weight infants.

BACKGROUND: Term (mature) human breast milk, compared with artificial formula milks, may provide insufficient nutrition for growth and development in preterm or low birth weight infants. However, human milk may confer advantages to infants in terms of a decreased incidence of adverse outcomes. OBJECTIVES: To determine if formula milk compared with term human breast milk leads to improved growth and development without significant adverse effects in low birth weight or preterm infants. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Review Group was used. This included electronic searches of the Cochrane Controlled Trials Register, MEDLINE, EMBASE and previous reviews including cross references. SELECTION CRITERIA: Randomised controlled trials comparing feeding with formula milk versus term human milk in low birth weight or preterm infants. DATA COLLECTION AND ANALYSIS: Data were extracted using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk, risk difference and weighted mean difference. MAIN RESULTS: Six trials, all initiated more than 20 years ago, fulfilled the pre-specified inclusion criteria. Four small trials compared feeding with standard calorie formula milk versus unfortified term human milk. Two trials compared feeding with calorie-enriched formula milk versus unfortified term human milk. No trials comparing feeding with formula milk versus nutrient-fortified term human milk were found. Only one trial reported longer term follow up of growth and development. In preterm and low birth weight infants, enteral feeding with formula milk compared with unfortified term human milk resulted in a greater rate of growth in the short term. We did not find a statistically significant difference in the incidence of necrotising enterocolitis, but this was evaluated as a pre-defined outcome in only one trial. The single trial that evaluated longer-term outcomes did not find evidence of an effect on longer-term growth and neurodevelopment. REVIEWER'S CONCLUSIONS: In preterm and low birth weight infants, feeding with formula milk, compared with unfortified term human milk, leads to a greater rate of growth in the short term. The limited data available do not allow definite conclusions on whether adverse outcomes, including necrotising enterocolitis, are increased in infants who receive formula milk compared with term human milk. There are no data from randomised trials on the comparison of feeding with formula milk versus nutrient-fortified breast milk. This limits the implications for practice of this review as nutrient fortification of breast milk is now a common practice in neonatal care. Future trials may compare growth, development and adverse outcomes in infants who receive adapted "preterm" formula milks versus nutrient-fortified human breast milk.

Humans↗
PubMed2001

Effects of amount of milk, milk flow and access to a rubber teat on cross-sucking and non-nutritive sucking in dairy calves.

The aim of this study was to test the effects of different amounts of milk, flow rate of milk, and access to a teat after milk intake on non-nutritive sucking on an empty teat and on cross-sucking on other calves in Bos taurus dairy calves. An additional aim was to test if calves prefer to perform non-nutritive sucking on a teat with the taste of milk or on a clean teat. First experiment involved 11 groups of three calves during gradual decrease from 5 to 2.5 and 1 to 0l of whole milk per meal twice daily. Milk flow was either 0.5 or 1l/min, and the teat buckets were either left or removed after milk intake. When the calves were fed with 5l of milk, non-nutritive sucking and cross-sucking decreased (P<0.001), compared to 1 and 2.5l. Removing the empty teat after milk intake increased cross-sucking (P<0.001). Slow milk flow reduced non-nutritive sucking after milk intake (P<0.05), but did not influence cross-sucking. Duration of recorded milk intake was similar with fast flow and 5l of milk, compared to slow flow and 2.5l of milk. The latter combination increased non-nutritive sucking and cross-sucking, suggesting that amount of milk is more important than duration of milk intake.Second experiment was carried out on 12 individually kept calves. The calves received 2.5l of milk either in an open bucket, in a rubber teat bucket, or half/half in both buckets. When not used for feeding, the open bucket and the teat bucket were filled and emptied again to make them 'tasty' with some drops of milk. The tasty teat bucket was either removed or present after milk intake. The calves had always access to a second clean teat bucket. Source of milk had no influence on recorded behaviour after milk intake. The tasty teat was sucked for twice as long as the clean one when both teats were present (P<0.001). When the tasty teat was removed, the calves increased sucking on the clean teat (P<0.001), but decreased total time spent sucking (P<0.001). We conclude that a high amount of milk and the presence of the teat bucket after milk intake reduces cross-sucking, and that a clean teat is less effective in encouraging calves to suck than a teat with taste of milk.

Journal Article↗
PubMed1999

Effect of feeding before, during and after milking on milk production and the hormones oxytocin, prolactin, gastrin and somatostatin.

Feeding during milking has been shown to influence milk production, milk flow and milking time as well as the secretion of the pituitary hormones oxytocin and prolactin, and the gastrointestinal hormone somatostatin. However, it is not known whether feeding before or after milking has any effect. The aim of the present study was to investigate how the timing of feeding relative to milking influences milk production and flow, milking time and hormone secretion. The trial was carried out over 9 weeks with 24 cows at varying stages of lactation. Each treatment period lasted for 3 weeks, including one registration week. The cows were fed ad lib. and were exposed to three treatments: feeding 1.5 h before milking (FBM), feeding at exactly the same time as milking (FDM) and feeding 1.5 h after milking (FAM). The most marked treatment effect was observed during morning milking. FDM resulted in higher milk production and higher yields of protein and lactose. FAM produced a lower fat yield and a lower fat content compared with FDM, and a lower lactose content than either FBM and FDM. Milking time was longer when cows were fed during milking, but no significant effects on milk flow were found. The amount of milk collected during the first 2 min of milking was lower when cows were fed after milking. Milking-related oxytocin and somatostatin secretion was lower in FAM than in FDM. The level of prolactin was lower when cows were fed before or after than during milking. More studies are needed to elucidate whether there is a long-term effect on milk production related to the discussed milking routines.

Animals↗
PubMed2005

Effects of week of lactation and genetic selection for milk yield on milk fatty acid composition in Holstein cows.

Control (CL) and select line (SL) dairy cows (n = 22) managed identically but differing in milk yield (>4100 kg/305 d) were used to determine differences in milk fatty acid profile as lactation progressed. Milk yield was recorded daily and milk samples were collected during wk 1, 4, 8, 12, and 16 postpartum for milk composition analysis. Milk samples from wk 1, 8, and 16 were also analyzed for fatty acid composition. Select-line cows produced more milk (44.4 vs. 31.2 kg/d) and milk components than CL cows during the 16-wk period. There was no difference in rate of milk yield increase, but peak milk yield for SL cows was greater and occurred later in lactation. There were no differences in milk SCC or milk fat, protein, or lactose content. Selection for milk yield did not affect the content of most individual milk fatty acids; however, compared with CL, SL cows had a reduced Delta(9)-desaturase system and tended to produce milk with lower monounsaturated fatty acid content. Selection for milk yield did not affect milk fatty acid origin but the percentage of de novo fatty acids increased and preformed fatty acids decreased as lactation progressed. Milk fat trans-11 18:1 and cis-9,trans-11 conjugated linoleic acid increased with progressing lactation (10.7 vs. 14.1 and 3.1 vs. 5.4 mg/g, or 31 and 76%, respectively) and were correlated strongly among wk 1, 8, and 16 of lactation. Temporal changes in the Delta(9)-desaturase system occurred during lactation but these changes were not correlated with milk fat cis-9,trans-11 conjugated linoleic acid content. Results indicate prolonged genetic selection for milk yield had little effect on milk fatty acid composition, but milk fatty acid profiles varied markedly by week of lactation.

Animals↗
PubMed1996

Milkability of Murciano-Granadina dairy goats. Milk partitioning and flow rate during machine milking according to parity, prolificacy and mode of suckling.

A total of 78 lactations (25 primiparous and 53 multiparous) in a herd of Murciano-Granadina dairy goats were studied over 3 years. Animals were allocated to two experimental groups: suckling (S) goats were milked once daily until weaning (week 7) and thereafter twice daily; milking (M) goats were milked twice daily from 2 d after parturition. Milk partitioning during milking (machine and machine stripping milk fractions) was recorded every week and the residual milk every 2 weeks. Milk flow rate was studied in 63 lactations on three consecutive days during week 12 or 13. Average machine and machine stripping milk fractions over 210 d were 1.09 and 0.23 l/d for the S and 1.23 and 0.28 l/d for the M group respectively. Machine milk volume and percentage were smaller in the S group during the first 7 weeks of lactation, while the machine stripping fraction was unaffected by group, indicating that this fraction was constant. The average residual milk was 11.1 and 9.2% of total milk in the S and M groups. Goats in their third lactation had the least residual milk (8.9%). Milk flow and total machine milk volume (but not milking time) were affected by parity, second and third lactation goats having higher values. Positive correlations were found between daily milk yield and milk flow characteristics. Residual milk was positively correlated with the machine stripping but not with the machine milk fraction. The results indicated that Murciano-Granadina goats can readily be machine milked, since > 80% of the milk can be obtained without massage or stripping.

Animals↗
PubMed2002

Effect of weaning system on milk composition and distribution of milk fat within the udder of East Friesian dairy ewes.

We investigated whether the inhibition of milk ejection during and/or between machine milkings is responsible for the low milk fat observed in commercial milk obtained from dairy ewes managed with a mixed system (MIX) of partial daily suckling (10 h) and once daily machine milking (after 14 h of udder filling). East Friesian crossbred dairy ewes were randomly allocated postpartum to the MIX system (n = 9) or to exclusive twice-daily machine milking (DY1, n = 8). Following wk 4, MIX ewes were permanently weaned from their lambs and milked twice daily. All ewes were injected with saline, oxytocin, or an oxytocin-receptor antagonist prior to three morning milkings during wk 2,4, and 6 of lactation to study cisternal and alveolar milk distribution. Overall milk yield (cisternal + alveolar) for MIX ewes was 42% greater than for DY1 ewes during wk 2 and 4, which demonstrates the beneficial effect of lamb suckling on milk production of dairy ewes. However, during normal machine milking, only the cisternal fraction was obtained from MIX ewes, confirming that milk ejection did not occur for as long as these ewes remained in partial daily contact with their lambs. Although the volume of milk stored within the cistern, and its concentration of milk protein was similar for the two weaning systems, milk of MIX ewes was significantly inferior in cisternal milk fat concentration and yield compared to DY1 ewes. This provides evidence that not only is there inhibition of milk ejection during machine milking of MIX ewes, there is additional inhibition of transfer of milk fat, but not milk protein, from the alveoli to the cistern during the evening when MIX ewes a reseparated from their lambs. Following weaning of MIX ewes, the majority of lactation traits studied were similar compared to DY1 ewes.

Animals↗
PubMed2006

Influence of raw milk quality on fluid milk shelf life.

Pasteurized fluid milk shelf life is influenced by raw milk quality. The microbial count and somatic cell count (SCC) determine the load of heat-resistant enzymes in milk. Generally, high levels of psychrotrophic bacteria in raw milk are required to contribute sufficient quantities of heat-stable proteases and lipases to cause breakdown of protein and fat after pasteurization. Sanitation, refrigeration, and the addition of CO2 to milk are used to control both total and psychrotrophic bacteria count. It is not uncommon for total bacterial counts of raw milk to be < 10,000 cfu/mL. In the past, fluid milk processors have not focused much attention on milk SCC. Increased SCC is correlated with increased amounts of heat-stable protease (plasmin) and lipase (lipoprotein lipase) in milk. When starting with raw milk that has a low bacterial count, and in the absence of microbial growth in pasteurized milk, enzymes associated with high SCC will cause protein and fat degradation during refrigerated storage, and produce off-flavors. As the ability to kill, remove, or control microbial growth in pasteurized refrigerated milk continues to improve, the original milk SCC will be the factor limiting the time of refrigerated storage before development of an off-flavor in milk. Most healthy cows in a dairy herd have a milk SCC < 50,000 cell/mL. Bulk tank SCC > 200,000 cell/mL are usually due to the contribution of high SCC milk from a small number of cows in the herd. Technology to identify these cows and keep their milk out of the bulk tank could substantially increase the value of the remaining milk for use in fluid milk processing. To achieve a 60- to 90-d shelf life of refrigerated fluid milk, fluid processors and dairy farmers need to work together to structure economic incentives that allow farmers to produce milk with the SCC needed for extended refrigerated shelf life.

Animals↗
PubMed1987

An evaluation of milk temperature measurement for detecting oestrus in dairy cattle. I. Factors affecting measurement of milk temperature.

The paper reports the development of an electronic system of milk temperature measurement and the results of investigations into the influence of milk yield, milk flow and ambient temperature on milk temperature. The milk and body temperatures of randomly selected multiparous Friesian cows were recorded at afternoon milkings. Temperature was measured by bead thermistors housed in perspex probes from which a digital read-out with an accuracy of +/- 0.1 degree C was obtained. Milk temperature was measured at four sites: the short milk tube (SMT), claw piece (CT), and the beginning (BLT) and end of the long milk tube (ELT) with readings being taken every 30 s from the commencement of milking. Body temperature measured with a probe in the vagina (VT) 38.85 +/- 0.02 degrees C) was significantly higher than milk temperature at any of the four sites although a significant positive correlation existed between milk and body temperature. Milk temperature measured at each site decreased with distance from the cows (SMT: 38.64 +/- 0.03 degrees C, ELT: 37.92 +/- 0.04 degrees C). The difference between body and milk temperature was greatest in cows in which milk flow rates were below average (less than 1.37 kg/min) and/or milk yields were below average (less than 7.82 kg/milking). Milk temperature sites SMT and CT were least affected by variation in milk yield or flow, and showed the closest relationship between maximum milk temperature and body temperature. Milk temperature measurement was most reliable when taken during the full flow of milk.

Animals↗