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PubMedDate not supplied

Oxytocin and milk removal: two important sources of variation in milk production and milk quality during and between milkings.

This review describes the effects of milking (routine and management) on milk yield and milk quality on dairy ruminants and examines the physiological effects of milking on the synthesis and secretion of milk. During milking, differences in the composition of milk as a result of milk ejection reflex are observed: the cisternal milk, immediately available, contains little fat, then milk ejection provokes active transport of high-fat content alveolar milk, into the cisternal compartment. Milking frequency has the capacity to affect milk production too. So, an increase in milking frequency augments milk yield whereas a decrease in milking frequency decreases milk production, with effects on milk composition. The milk ejection reflex is mediated by oxytocin, which induces myoepithelial cell contraction. Nevertheless, other actions of oxytocin may exist, such as a direct effect on proliferation and differentiation of myoepithelial cells and on secretory processes in the mammary epithelial cells.

Animals↗
PubMed1993

The effects of daily oxytocin injections before and after milking on milk production, milk plasmin, and milk composition.

Exogenous daily oxytocin injections given immediately before milking increase milk production. To investigate the mechanism by which oxytocin increases milk production, oxytocin injections were given before and after milking, and saline injection was given before milking as a control. The experimental design was a replicated Latin square; two complete trials were performed: one with 12 cows (45 d) and another with 15 cows (95 d). In the first trial, the least squares means of milk production were 29.2, 29.3, and 28.3 kg for oxytocin injection before milking, oxytocin injection after milking, and saline injection before milking, respectively. In the second trial, the least squares means of milk production were 33.3, 32.9, and 32.4 kg for oxytocin injection before milking, oxytocin injection after milking, and saline injection before milking, respectively. Oxytocin before and after milking significantly increased milk production by 3%. The results suggest that increases in milk production may not be caused by removal of residual milk but by increased gland output of milk. The effect on milk plasmin activity, fat, protein, SCC, and lactose was nonsignificant and may indicate that effect of oxytocin is not manifested through an effect on cell remodeling.

Animals↗
PubMed2003

Feeding behavior, milking behavior, and milk yields of cows milked in a parlor versus an automatic milking system.

This study compared feeding and milking behavior and milk yields for cows housed in the same barn, fed the same ration, but milked with a conventional milking parlor (parlor) or automatic milking system (robot). Behavioral data were videotaped hourly 1 d/mo for 9 mo. Feeding behavior patterns differed and were more variable for parlor cows than for robot cows. Both groups had low feeding rates at night and early morning. Feeding activity increased after milking and feed delivery for parlor cows. Milking and feeding activity in the robot system increased after human intervention at 7 a.m.; feed bunk activity peaked 3 h later and remained relatively constant from 10 a.m. to 8 p.m. Percentages of cows at the feed bunk were significantly greater for robot cows than parlor cows only at 10 a.m. and 9 p.m. Batch milking of parlor cows with free access to feed, vs. sequential milking of robot cows, with restricted movement to feed by a one-way gate system, resulted in higher peak percentages of cows at the bunk for parlor cows. Lower, more consistent percentages of cows eating at one time suggests that less bunk space may be needed for cows in robotic milking systems. Higher percentages of cows were observed in the robot from 8 a.m. to 1 p.m. and again from 3 to 7 p.m. Percentages of cows in the robot holding area were greatest from 8 to 11 a.m. and 3 to 6 p.m. and were lowest from midnight to 6 a.m. Milk production over 39 d in summer for subsets of cows was slightly but significantly higher (26.4 vs. 25.8 +/- 0.2 kg/d) for cows in the robot group. Milking frequency, days in milk, parity, and maximum air temperature for 3 d (-2 d to day of observation) affected milk yield comparisons. Results have implications for design of feeding and handling facilities used with automated milking systems.

Animals↗
PubMed1992

Prospective estimation of IgG, IgG subclass and IgE antibodies to dietary proteins in infants with cow milk allergy. Levels of antibodies to whole milk protein, BLG and ovalbumin in relation to repeated milk challenge and clinical course of cow milk allergy.

Prospectively, serum levels of IgE, specific IgE antibodies (AB) to whole cow milk protein (CMP), bovine se-albumin, bovine immunoglobulin, bovine lactoferrin, bovine lactalbumin and beta-lactoglobulin (BLG), IgG and IgG subclass antibodies to ovalbumin (OA) and BLG, and IgG4 RAST to CMP (bovine whey) were measured in 39 infants with cow milk protein allergy (CMPA) at birth (cord blood), at time of diagnosis and before and after milk challenge at the age of 12 months. Immunological measurements were also undertaken in 33 control infants without CMPA at birth, at 6 months and at 18 months. At no time, were differences found between the levels of IgG and IgG subclass AB to OA and BLG in control versus infants with CMPA. In the 39 infants with CMPA no correlation was found between the levels of IgE, IgG and IgG subclass AB in cord blood and subsequent levels of these values, irrespective of the type of CMPA (IgE-mediated (CMA) or non-IgE-mediated (CMI)), and irrespective of whether remission had occurred. In cord blood 25/33 (76%) of the infants with CMPA had specific IgE-AB to one or more of the bovine milk proteins indicating a prenatal intrauterine sensitization to cow milk protein. At 6 months the frequency of specific IgE-AB to bovine milk proteins was significantly (p less than 0.05) higher in infants with CMA versus CMI, and at 12 months total serum-IgE and the increase of these specific IGE-AB and RAST to CMP were significantly higher (p less than 0.05) in infants with persistent CMA. From 6 to 12 months withholding milk resulted in a significant fall in specific IgE-AB to CMP, and IgG, IgG1 and IgG4 anti-BLG followed by an increase after milk challenge. Decreasing levels of IgG anti-OA from birth to 6 months reflect passive maternal transfer of IgG through the placenta, and increasing levels of IgG anti-BLG, already from birth to 6 months, may represent an early exposure to CMP in all infants. Significantly higher levels (p less than 0.05) of IgG anti-OA AB, IgG1 and IgG4 anti-BLG AB were found in infants with persistent CMA, indicating a close relation between the synthesis of IgE and IgG and between IgE and IgG subclasses (IgG1 and IgG4) in symptomatic cow milk-allergic individuals.(ABSTRACT TRUNCATED AT 400 WORDS)

Child, Preschool↗
PubMed1991

An evaluation with piglets of bovine milk, hydrolyzed bovine milk, and isolated soybean proteins included in infant milk formulas. II. Stomach-emptying rate and the postprandial change in gastric pH and milk-clotting enzyme activity.

The piglet was used as a model for the human infant to determine the effect of the protein source of a milk formula on stomach-emptying rate and the postprandial changes in gastric pH and milk-clotting enzyme activity. Three liquid milk formulas containing either intact bovine milk protein, hydrolyzed bovine milk protein, or isolated soybean protein as the sole source of dietary protein were given to five 37-day-old piglets that had undergone surgery for the preparation of a simple gastric fistula. At set times after commencement of a meal, the stomach contents were removed via a gastric cannula and weighed; then pH and milk-clotting enzyme activity were determined. The isolated soybean protein-based formula tended to empty from the stomach more slowly than did the bovine milk-based formulas. Maximum difference (p less than 0.05) was found at 3 h postfeeding, where 30% of the ingested soybean formula dry matter remained in the stomach; comparable values for the intact bovine milk-based formula and hydrolysate were 22 and 12%, respectively. The type of protein did not significantly (p greater than 0.05) affect the postprandial change in gastric pH or gastric milk-clotting enzyme activity. Gastric pH increased sharply after feeding, from pH 1.5 at 0 h to pH 5.2 at 1 h, and then fell gradually over the following 4 h to pH 1.84.

Analysis of Variance↗
PubMed1987

The effect of goat milk fractions on synthesis of milk constituents by rabbit mammary explants and on milk yield in vivo. Evidence for autocrine control of milk secretion.

Lactose and casein synthesis by rabbit mammary explants in organ culture was inhibited when fractions of goat milk were included in the culture medium. Inhibition was dose-dependent, and readily reversed when milk fractions were removed. The pattern of effects obtained with various fractions of milk indicated that inhibition was caused by a protein of 10,000-30,000 Da, which was present in the milk serum or whey fraction. The inhibitor fraction decreased milk accumulation when injected into lactating rabbit mammary glands via the teat ducts, whereas other milk proteins had no effect. Results are discussed in terms of autocrine regulation of milk synthesis through negative feedback by milk constituents.

Animals↗
PubMed1988

A prospective study of cow's milk allergy in exclusively breast-fed infants. Incidence, pathogenetic role of early inadvertent exposure to cow's milk formula, and characterization of bovine milk protein in human milk.

A cohort of 1,749 newborns in the municipality of Odense were followed prospectively for the development of cow's milk allergy (CMA) during their first year of life. Altogether 39 fulfilled the criteria for CMA (2.2%). Out of the 39 infants, 17 developed symptoms of CMA during breast-feeding, in all cases before the age of 3 months. Nine of these were solely breast-fed at the time of diagnosis, giving a one year incidence of CMA in exclusively breast-fed infants of 0.5% (9/1,749) in a study population with a frequency of exclusive breast-feeding of 52% at 3 months of age. None of the infants had signs of CMA in the neonatal period. Review of records from the newborn nursery revealed that all 9 infants had been exposed to cow's milk formula in amounts corresponding to approximately 0.4-3.0 g of beta-lactoglobulin (BLG) during the first three days of life. Human milk samples were analyzed by enzyme-linked immunosorbent assay (ELISA) for the content of bovine BLG. Detectable amounts (0.5-45 ng/ml) were found in 3/9 samples of human milk against which the infants reacted clinically. Analysis of the size distribution by high pressure liquid gel permeation chromatography in combination with ELISA indicated a molecular weight of BLG corresponding to that of monomeric BLG (18 kD). Possibly early inadvertent and occasional exposure to cow's milk proteins may initiate sensitization in predisposed neonates. Subsequent exposure to minute amounts of bovine milk proteins in human milk may act as booster doses eliciting allergic reactions.

Animals↗
PubMed2001

Continuous nasogastric milk feeding versus intermittent bolus milk feeding for premature infants less than 1500 grams.

BACKGROUND: Most premature infants less than 1500 grams birth weight must be fed initially by tube because of their inability to suck effectively, or to coordinate sucking, swallowing and breathing. Milk feedings can be given by tube either intermittently, typically over 10-20 minutes every two or three hours, or continuously, using an infusion pump. Although theoretical benefits and risks of each method have been proposed, effects on clinically important outcomes remain uncertain. OBJECTIVES: To examine the evidence from randomized trials regarding the effectiveness of continuous versus intermittent bolus nasogastric milk feeding in premature infants less than 1500 grams. The primary outcomes reviewed included feeding tolerance, days to reach full enteral feeding, somatic growth, days to discharge and incidence of necrotizing enterocolitis (NEC). SEARCH STRATEGY: Searches were performed of MEDLINE, CINAHL, HealthSTAR, and the Cochrane Controlled Trials Register. As well, studies identified from abstracts and conference proceedings and references from relevant publications were retrieved. SELECTION CRITERIA: Randomized and quasi-randomized clinical trials that met the following criteria for relevance: a) Enrollment of infants < 1500 grams birth weight with no major congenital anomalies which might interfere with feeding tolerance b) Comparison of continuous nasogastric versus intermittent bolus tube feedings using breastmilk or formula c) Assessment of relevant outcomes including feeding tolerance, days to full feeds, somatic growth, days to discharge, and complications such as NEC or apnea DATA COLLECTION AND ANALYSIS: All articles retrieved from the complete search were assessed independently by the two reviewers for relevance (see selection criteria), and for methodologic quality using the following criteria: blinding of randomization, blinding of intervention, complete follow-up and blinding of outcome measurement. Only those articles judged by both reviewers to be relevant and to have appropriate methodologic quality were included in the analysis. Differences were resolved through discussion and consensus of the reviewers. MAIN RESULTS: Infants fed by continuous tube feeding method took longer to reach full enteral feeds (weighted mean difference 3.0 days; 95% CI 0.7, 5.2). Although there was no evidence of a difference in the days to discharge overall, one study suggested a trend toward earlier discharge for infants less than 1000 grams birth weight fed by the continuous tube feeding method (mean difference (MD) -11days; 95% CI -21.8, -0.2). Overall, there was no evidence of a difference in somatic growth (weight, length, head circumference or skinfold thickness) between the two groups, but subgroup analyses in one study suggested that infants less than 1000 grams and 1000 - 1250 grams birthweight gained weight faster when fed by the continuous tube feeding method (MD 2.0 g/day; 95% CI 0.5, 3.5; MD 2.0 g/day; 95% CI 0.2, 3.8, respectively). There was no evidence of a difference in the incidence of NEC. One study showed a trend toward more apneas during the study period in infants fed by the continuous tube feeding method (MD 14.0 apneas during study period; 95% CI -0.2, 28.2). REVIEWER'S CONCLUSIONS: Infants fed by the continuous tube feeding method took longer to reach full feeds, but there was no difference in somatic growth, days to discharge, or the incidence of NEC for infants fed by continuous versus intermittent bolus tube feeds. Small sample sizes, methodologic limitations and conflicting results of the studies to date, together with inconsistencies in controlling variables that may affect outcomes, make it difficult to make universal recommendations regarding the best tube feeding method for premature infants less than 1500 grams. The clinical benefits and risks of continuous versus intermittent nasogastric tube milk feeding cannot be reliably discerned from the limited information available from randomized trials to date.

Enteral Nutrition↗
PubMed1996

Simultaneous recording of oxytocin release, milk ejection and milk flow during milking of dairy cows with and without prestimulation.

The effects of manual teat stimulation compared with stimulation by the liner of a conventional milking machine and the influence of milk ejection on the course of milk flow during the entire milking were investigated. Twelve cows were milked with or without prestimulation on three quarters and milk flow was recorded while intramammary pressure (IMP) was recorded in the left front quarter and blood samples for the determination of oxytocin (OT) were taken at 1 min intervals. OT concentrations increased very similarly in response to manual teat stimulation or liner stimulation and remained elevated during the entire milking procedure. Milk flow curves were generally bimodal without stimulation and not bimodal during milking after prestimulation. Milk yield was not significantly lower in milkings without than with stimulation, whereas machine-on time was prolonged and peak milk flow rate was reduced during milking without stimulation. Time to reach milk flow plateau, time to reach peak flow rate and IMP profiles were similar in both treatments if time was calculated from the start of stimulation. IMP increased similarly in response to manual or liner teat stimulation. In milkings with and without prestimulation IMP did not reach its maximum until the start of milking. In bimodal milk flow curves the second increase of milk flow occurred concomitantly with the start of IMP increase; ejection IMP generally occurred concomitantly with the milk flow plateau. In some cases during milking without prestimulation only small and transient CT release was observed. In response, IMP did not increase to its maximum and increased further in response to a stripping-related CT release. During the course of milking IMP decreased slightly because of the emptying of the three milked quarters. After the end of milking, and with CT concentrations decreasing to the premilking values, IMP again decreased slightly to another plateau, probably owing to myoepithelial relaxation. Thus the course of milk ejection, i.e. the IMP profile, influenced milk removal markedly during early milking.

Animals↗
PubMed1999

Influence of pig substitution on milk yield, litter weights, and milk composition of machine milked sows.

This study was conducted to 1) determine milk yield of sows that were machine milked up to four times daily; 2) determine the effect of pig substitution on milk yield; 3) assess litter weight changes for sows that are milked; and 4) determine milk composition. Eight sows were milked four times daily to d 51 postpartum. Sows either maintained their own litter or had a week-old replacement litter to replace 25-d-old pigs. Individual gland milk yields were obtained on random days throughout lactation, and different diameter and weighted teat cups were rotated so that all glands received all combinations. Composite milk samples were analyzed for fat, protein, and somatic cells. Milk yields peaked at about 19 d postpartum and declined to 45 d postpartum in sows with their own litter, whereas milk yields peaked earlier and had a more dramatic decline after fostering of a younger litter. Litter weights were 17.1 +/- 1.0 kg at farrowing with 13.6 +/- .6 pigs born alive. Final litter weights were 34.4 +/- 11.7 kg for sows with replacement litters and 74.4 +/- 13.5 kg for sows with their own litters, and numbers of pigs weaned were 6.5 +/- 1.3 and 9.7 +/- 1.5, respectively. Milk fat was influenced by route of oxytocin administration (6.53 +/- .12 for i.v. vs 7.21 +/- .19% for i.m. administration; P < .05). Milk fat percentage was highest on d 2 and declined to 13 d postpartum. Milk protein was influenced by time of day of milking (lowest at the fourth milking, 5.57 +/- .11%) and followed a pattern similar to that for milk fat. Milk protein was affected in a linear manner by milk yield, with highest protein associated with lowest milk yields. Somatic cells in milk were influenced by litter replacement (P < .05) and oxytocin administration (P < .01). There was a linear increase in somatic cells from about 8 x 10(6) cells/mL milk at d 2 to more than 12 x 10(6) cells/mL milk at d 51 postpartum. These results show that pig replacement affects the amount of milk obtained. Moreover, milk composition changes throughout lactation. However, milk removal from sows has a severe impact on litter weight gains, and in systems where sow's milk is needed for commercial purposes, pig supplementation is necessary.

Analysis of Variance↗
PubMed2002

Investigations on milk flow and milk yield from teats with milk flow disorders.

The objective of this study was to investigate peak milk flow, average milk flow, and milk yield in teats with milk flow disorders. A total of 100 hard milking teats were studied in 97 cows. Teats with milk flow disorders were examined endoscopically. Quarter milk flow and quarter milk yield were examined with four Lactocorders attached to a quarter milking machine. Peak milk flow, average milk flow, and milk yield were measured in all teats of the udder before treatment of the affected teat, as well as 1 and 6 mo later. Teats with milk flow disorders were compared to all other teats of the same udder. Before treatment, peak milk flow from affected teats was 20%, average milk flow 14%, and milk yield 53% of the control teats, adjusted for other significant explanatory variables. Milk flow and milk yield increased after surgical treatment of the affected teats. Six months after treatment peak milk flow was 79%, average milk flow 76%, milk yield was 71% compared with control teats. We conclude from these findings that teat endoscopy and measuring quarter milk flow and milk yield with Lactocorders are useful tools for examining teats with milk flow disorders.

Animals↗
PubMed1999

Intestinal barrier function and cow's milk sensitization in guinea pigs fed milk or fermented milk.

BACKGROUND: The respective effect of milk and fermented milks on intestinal barrier capacity and on sensitization to beta-lactoglobulin was studied using a guinea pig model of cow's milk allergy. METHODS: Guinea pigs were fed a control diet or the same diet supplemented with milk, fermented milk (Streptococcus thermophilus and Bifidobacterium breve), or dehydrated fermented milk. Intestinal barrier capacity to macromolecules was assessed in an Ussing chamber, and sensitization to cow's milk proteins was measured by systemic anti-beta-lactoglobulin immunoglobulin G1 titers and by intestinal anaphylaxis, the latter assessed by the beta-lactoglobulin-induced increase in short-circuit current of jejunal fragments (deltaIsc(beta-LG)). RESULTS: The electrical resistance of jejunum was similar in the four groups (approximately 80 omega/cm2) suggesting the same paracellular permeability. The transport of 14C-beta-lactoglobulin from mucosa to serosa was significantly decreased in the animals fed dehydrated fermented milk (403+/-131 ng / hr x cm2) compared with that in control animals or animals fed milk (767+/-250 ng / hr x cm2 and 749+/-475 ng / hr x cm2, respectively; p < 0.05). Milk fermentation did not modify native beta-lactoglobulin concentration but anti-beta-lactoglobulin immunoglobulin G1 titers were higher in fermented milk and dehydrated fermented milk (log10 titer = 2.86 and 2.79, respectively) than in guinea pigs fed milk (log10 titer = 2.5; p < 0.007). However, beta-lactoglobulin-induced intestinal anaphylaxis remained the same in the three groups (deltaIsc(beta-LG), 9.6+/-4.1 microA/cm2, 8.5+/-4.3 microA/cm2, and 8.5+/-3.4 microA/cm2 in milk-fed, fermented milk-fed, and dehydrated fermented milk-fed guinea pigs, respectively). CONCLUSIONS: The intestinal barrier capacity to milk proteins seems to be reinforced by dehydrated fermented milk, but milk and fermented milks are equally efficient in inducing cow's milk allergy in guinea pigs.

Animals↗
PubMed2003

Effects of once versus twice daily milking throughout lactation on milk yield and milk composition in dairy goats.

The effects of once (1X) vs. twice (2X) daily milking throughout lactation on milk yield, milk composition, somatic cell count (SCC), and udder health were studied in 32 Murciano-Granadina dairy goats. Goats were assigned at wk 2 of lactation to two treatment groups; once daily milking at 0900 (1X, n = 17), or twice daily milking at 0900 and 1700 (2X, n = 15). Milk yield was recorded weekly until wk 28, and milk composition and SCC were evaluated for each individual udder half at each milking at wk 2 and 4 of lactation and then, monthly until the end of the experiment. Once daily milking resulted in an 18% reduction in the yield of 4% fat-corrected milk compared to twice daily milking (1.61 vs. 1.95 L/d, respectively). This reduction was more marked from wk 2 to 12 than in mid and late lactation. Response to milking frequency also varied according to parity number where goats of less than four parities suffered more milk yield losses during 1X than older goats. Milk of 1X goats contained higher percentages of total solids (13.6 vs. 12.9%), fat (5.10 vs. 4.62%) and casein (2.57 vs. 2.35%) than milk of 2X goats, but milk protein percentage did not differ between treatments (3.28 vs. 3.20%). Yields of total solids, fat, protein and casein tended to be higher for 2X than 1X. Milk SCC did not differ between treatments. We conclude that application of once daily milking in Murciano-Granadina dairy goats moderately reduced milk yield without negative effects on milk composition and udder health. Losses in milk yield would be reduced if 1X is practiced during mid- or late lactation and in older goats. An increase in labor productivity and a higher farmer's standard of living is also expected.

Animals↗
PubMed2002

Effect of milking interval on alveolar versus cisternal milk accumulation and milk production and composition in dairy ewes.

Cisternal and alveolar milk fractions were measured in East Friesian crossbred dairy ewes (n = 32) after 4, 8, 12, 16, 20, or 24 h of milk accumulation in a 6 x 6 Latin square design by administration of an oxytocin receptor antagonist for recuperation of cisternal milk followed by injection of oxytocin to remove the alveolar fraction. Less than half (38 to 47%) of the total milk yield was stored within the cistern for the first 12 h of udder filling compared with up to 57% after 24 h of udder filling. Subsequent milk yield was significantly reduced following the 16-, 20-, and 24-h treatments. Cisternal milk fat percentage, but not milk protein percentage, was lower than in alveolar milk (4.49 vs. 7.92% milk fat, respectively), indicating that casein micelles pass more freely from the alveoli to the cistern between milkings compared with fat globules. Alveolar compared to cisternal somatic cell count was higher for the 16-, 20-, and 24-h treatments. Significant increases in cisternal milk yield and milk composition observed for the 24-h compared with the 20-h treatment demonstrated the importance of the cistern as a storage space when the alveoli and small intramammary ducts became full. The main difference between cisternal and alveolar milk fractions is the poor fat content of cisternal milk, which is an important reason for the milk ejection reflex to be present during machine milking of dairy ewes. In a second experiment, milking every 16 h compared with every 12 h during mid- to late-lactation did not effect milk yield, milk composition, and quality, or lactation length; however, a 25% savings in labor was achieved with the longer milking interval.

Animals↗
PubMed1997

Machine milking of Ostfriesian and Lacaune dairy sheep: udder anatomy, milk ejection and milking characteristics.

Mammary cistern anatomy derived from ultrasound measurement, milk ejection in response to exogenous oxytocin and oxytocin release and milking characteristics with and without manual prestimulation in early (months 2-4) and late (months 5-8) lactation were investigated in Lacaune and Ostfriesian dairy ewes. Vertical ultrasound cisternal cross sections of the cisternal cavities did not differ in the two breeds, whereas the cisternal area fraction located lower than the exit into the teat channel was larger in Ostfriesian than in Lacaune sheep. The cisternal area enlarged within 1 min in response to i.v. oxytocin injection, indicating milk ejection. During milking, oxytocin concentrations in Lacaune generally increased dramatically within 0.5 min from the start of prestimulation or milking, whereas only slight or no oxytocin release was detected during milking without prestimulation in Ostfriesian ewes. Prestimulation induced oxytocin release in Ostfriesian sheep within 1-2 min after the start of milking, indicating delayed response to stimulation. Two peaked milk flow curves were observed when oxytocin release and milk ejection occurred only after removal of cisternal milk. This type of milk flow was more frequent in Ostfriesian than in Lacaune ewes and was reduced in both breeds by prestimulation, while the frequency of one peaked milk flow curves increased. During the course of lactation, milk yield, main milk fraction and milk flow rates decreased, while stripping yield was almost unchanged. Although milk yield was similar in both breeds, milk flow was lower and stripping yield was higher in Ostfriesian than in Lacaune ewes. We conclude that milk ejection in ewes occurred in response to elevated oxytocin concentrations. In Ostfriesian ewes reduced and delayed oxytocin response to teat stimulation resulted in milk ejection only during stripping. Therefore, and probably because a larger volume of the cistern was located below the teat exit in the Ostfriesian breed, stripping yield was higher in Ostfriesian than in Lacaune sheep.

Animals↗
PubMed1998

Reduction of serum cholesterol and low-density lipoprotein cholesterol levels in a juvenile population after isocaloric substitution of whole milk with a milk preparation (skimmed milk enriched with oleic acid).

OBJECTIVE: To study the effects of serum lipid levels by isocaloric substitution of whole milk intake in a group of children with a milk preparation (fat-free milk enriched with oleic acid containing a small amount of cholesterol) that is frequently consumed in our community. DESIGN: A crossover clinical trial was carried out with random selection. There were 88 children of both sexes, ranging in age from 3 to 9 years, selected at a Primary Care Center. The children were divided into two homogeneous groups. The first group consumed whole milk for the first 7-month study period, whereas the second group drank the milk substitute. At the end of the first test period, serum lipid levels were measured. Then the type of diet was reversed: Group 1 children consumed the milk substitute whereas Group 2 children drank whole milk. The rest of their intake did not vary throughout the study. At the end of the second 7-month period we measured serum lipid levels again. The levels of serum lipid evaluated were total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, Apoprotein A1, Apoprotein B, and lipoprotein (a). For the statistical analysis the nonpaired and paired t tests were used. RESULTS: The mean level of cholesterol after taking whole milk was 4.53 mmol/L (175.26 mg/dl), and the mean level after taking the milk preparation was 4.2 mmol/L (162.65 mg/dl), which indicates a 7.2% decrease. The mean level of low-density lipoprotein cholesterol after whole milk intake was 2.73 mmol/L (106.1 mg/dl), whereas after consuming the milk preparation it was 2.47 mmol/L (96.1 mg/dl), which indicates a decrease of 9.5%. Triglycerides were reduced from 0.83 mmol/L (73.53 mg/dl) after whole milk to 0.72 mmol/L (63.79 mg/dl) after the milk substitute, which suggests a 13.25% decrease. High-density lipoprotein cholesterol, apoprotein A1, apoprotein B, and lipoprotein (a) did not undergo any significant change. CONCLUSIONS: To reduce serum levels of total cholesterol and low-density lipoprotein cholesterol, without reducing caloric intake, it may be beneficial to substitute the whole milk customarily consumed by children with a milk preparation of fat-free milk enriched with oleic acid.

Animals↗
PubMedDate not supplied

[The correlation between milk flow, vacuum fluctuations and decrease in vacuum in the long milk tube at the claw in different milking machines. An introductory examination (author's transl)].

Four different milking machines have been examined for vacuum fluctuations and vacuum decrease in the long milk tube at the claw. Measurements were performed in 3 cows milked with Alfa-Laval high line HP 100, 11 cows in 3 herds milked with Alfa-Laval high line Duovac 300, 5 cows milked with Erland low line milking equipment, and in 3 cows milked with Strangko high line milking equipment. The recordings were done in the cowhouse during the daily dairy management. The milk flow for each cow was measured 24 hrs after the vacuum recordings using Milko-Scope. Compared to the other 3 milking machines, Duovac 300 had a significant higher increase in vacuum fluctuations and vacuum decrease with the increase in milk flow. Just small differences existed between Alfa-Laval HP 100 and Strangko milk pipe line equipments. Smaller vacuum fluctuations and vacuum decrease were recorded in the low line milking equipments compared to the other types. The difference was significant (P = less than 0.001). Significant correlations between milk flow and decrease in vacuum, and between milk flow and vacuum fluctuations were not found for the low line milking machine examined.

Animals↗