Once-daily Milking Research Articles

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.

Combined effects of once-daily milking and feeding level in the first three weeks of lactation on milk production and enzyme activities, and nutritional status, in Holstein cows

Effets de la traite une fois par jour combinee au niveau d'alimentation pendant les trois premieres semaines de la lactation sur la production et les activites enzymatiques du lait, et l'etat nutritionnel, chez des vaches Holstein. Vingt-quatre vaches multipares ont ete reparties des le velage en 4 lots, selon un schema factoriel 2 x 2: 2 frequences de traite (1 traite par jour pendant les 3 premieres semaines de lactation, puis 2 traites par jour vs. 2 traites par jour en permanence) x 2 concentrations energetiques de la ration (normale ou basse). L'essai a dure en moyenne 30 semaines et s'est termine au pâturage, le 28 mai 2000. Pendant la periode hivernale, les vaches etaient logees ensemble dans une stabulation libre a logettes et recevaient a volonte une ration complete. La traite omise etait celle du soir. Les vaches non traites ont emis significativement plus de vocalisations que les temoins autour de la traite omise, et elles ont ete plus nombreuses a perdre du lait. La traite 1 fois par jour a progressivement reduit la quantite de lait secretee par rapport a celle produite par les vaches traites 2 fois par jour, l'ecart atteignant 8,5 kgj -1 (P 0,10) pour l'ensemble de l'essai. La traite 1 fois par jour n'a pas affecte la teneur du lait en matieres grasses, en proteines (vraies), en albumine serique, et en lactose, ni le nombre de cellules somatiques ou l'activite de la plasmine et celle induite par l'activation du plasminogene. Elle a accru la teneur en immunoglobulines G1 (P = 0,02; mesure a la semaine 3) et a diminue l'activite de la lipoproteine lipase, ce qui n'avait pas encore ete rapporte. Elle a ameliore l'etat nutritionnel en debut de lactation (pertes de poids vif et d'etat corporel reduites, bilan energetique calcule accru) et n'a eu aucun effet sur la quantite de ration ingeree. La ration de concentration energetique normale a entraine, par rapport a celle de concentration energetique basse, les effets attendus: accroissement significatif des quantites ingerees (1,2 kg MSj -1 ), de la quantite de lait produite (3,1 kgj -1 ), de son taux proteique (2,0 gkg -1 ) et des index nutritionnels, notamment. La reduction de quantite de lait produite au cours des 3 premieres semaines de la lactation entrainee par la traite 1 fois par jour a ete de 5,5 kgj -1 et 8,5 kgj -1 respectivement pour les lots recevant les rations de concentration energetique faible ou normale (interaction non significative; P > 0,10).

Advances in bovine theriogenology in New Zealand. 1. Pregnancy, parturition and the postpartum period

Unique systems of breeding and calving management have been developed to allow New Zealand cattle herd owners to maintain seasonally concentrated calving patterns. Improved pastures are used as the sole ration for most beef and dairy cows with limited conservation and no grain feeding. Patterns of calving are described in relation to herd Planned Start of Calving (PSC) dates, calculated as 282 days after the first date of insemination in the preceding seasonal artificial breeding (AB) programme. Corti-costeroids have been systematically used in over 80% of New Zealand dairy herds to induce premature parturition (calving induction) during the third trimester of pregnancy for about 25 years, to condense calving patterns into periods of 6-12 weeks. Widespread use of calving induction has minimised the adverse effects of declining reproductive performance in dairy herds on the sustainability of seasonally concentrated calving. The use of calving induction is now discouraged on animal welfare grounds and due to possible consequences for the marketing of New Zealand dairy products. Recent declines in the reproductive performance of dairy herds are linked to increased prevalence of extended periods of postpartum anovulatory anoestrus (AA), which has become the major form of infertility in dairy herds in New Zealand and can be related to reliance on grazed pasture as the sole diet for cows of increasing genetic merit The prevalence of AA is influenced by parity, breed, recent genetic origin within a breed, body condition score, herd and year. Management strategies such as oncedaily milking, preferential grazing or feeding of silage, have not proven as successful as hormonal treatments. Although seasonally concentrated calving has remained a standard feature of the industry's low-cost, pasture-based system of management, continuing research will be required to economically maintain this pattern.

Effect of Milking Frequency on Mammary Functioning and Shape of the Lactation Curve

Milk yield is a function of the number of mammary secretory cells and their metabolic activity. Both are not static, but change during the course of lactation. The rate at which they change may be influenced by farm management practices, such as feeding, photoperiod, hormonal treatment (e.g., bovine somatotropin), and milking frequency. By applying such practices, or a combination thereof, at any time during lactation, the farmer has tools to alter the shape of the lactation curve. These practices could be applied after peak lactation to increase milk yield and perhaps slow down the rate of postpeak decline in milk yield, but can also be used to promote mammary involution near drying-off. The present review focuses on milking frequency. Compared with twicedaily milking, milking three times a day or more often (robotic milking) will increase milk yield by 18%, whereas once-daily milking decreases milk output by 20%. Although frequent milking is practiced more often than once daily, the once-daily milked gland provides an excellent model to study functional changes related to milking frequency. The effects of increasing and decreasing milking frequency on mammary functioning are discussed, with emphasis on functional changes in the once-daily milked gland with regard to processes such as changing cell number or activity, feedbackinhibition, tight junction leakiness, apoptosis, and cisternalalveolar milk storage.

Production responses of tropical crossbred cattle to supplementary feeding and to different milking and restricted suckling regimes

The relationships between cow nutrition, restricted suckling and milking patterns and their effect on milk yield, milk composition and calf growth were examined under tropical conditions in south east Mexico. Eleven Bos indicus× Bos taurus cows, 14 days postpartum, with calves weighing on average 37 kg were used in a change-over experimental design. All cows were fed Cynodon nlemfuensis hay ad libitum, and either 4.0 kg Leucaena leucocephala, 2.0 kg sorghum grain and 0.25 kg sugar-cane molasses on a fresh weight basis (L1), or twice this amount of the same supplement (L2). The calves were offered the same hay ad libitum in addition to suckling milk. The milking/restricted suckling treatments were: twice-daily milking with suckling after morning milking (2×AM), and once-daily milking in the morning with afternoon suckling (1×PM). The two regimes were examined at L1 and L2 feeding levels. A suckling time of 30 min was allowed at each suckling occasion. For 2×AML1, 2×AML2, 1×PML1 and 1×PML2, respectively saleable milk yields (SMYs) (kg/day) were 5.43, 5.99, 3.47, 4.09 (S.E.M. 0.174); calf suckled milk (CSM) (kg/day) 1.36, 1.46, 3.14, 3.43 (S.E.M. 0.160); and total milk yield (kg/day) 6.79, 7.46, 6.62, 7.53 (S.E.M. 0.226). For SMYs, fat contents (g/kg) were 30.0, 29.4, 29.0, 28.7 (S.E.M. 1.11), respectively, and for CSM 59.6, 63.4, 38.8, 42.4 (S.E.M. 2.46). Protein contents (g/kg) for SMYs were 27.5, 29.1, 29.3, 30.4 (S.E.M. 0.67) and for CSM 27.9, 28.4, 29.1, 30.3 (S.E.M. 0.81). Total food intakes of cows were 10.84, 12.12, 10.99, 12.16 (S.E.M. 0.331) kg DM/day. Calf growth rates were, respectively, 0.17, 0.20, 0.41, 0.52 (S.E.M. 0.029) kg/day, and hay DM intake 0.58, 0.49, 0.41, 0.34 (S.E.M. 0.040) kg/day. It was concluded that level of supplementation and restricted suckling and milking regimes could both be used to manipulate TMY, SMY and calf performance.

Regulation of yield loss and milk composition during once-daily milking: a review

Once-daily milking (ODM) of ruminants results in loss of milk production. In cows this loss is very variable between individuals but in recent short-term trials, on average, the loss was 13%. Full lactation studies indicate losses of 35–50% but documentation from some commercial farms using ODM suggests that losses are lower. ODM also results in changes in mammary permeability leading to changes in milk composition through increased influx of serum proteins and ions and increased efflux of lactose and potassium. Somatic cell count is also increased by ODM. Yield loss occurs through a combination of acute and chronic changes in mammary function. Anatomical and physiological characteristics which are likely to minimise production losses on ODM include production of a concentrated milk, possession of a large cistern, good drainage from the alveolar compartment and a low initial somatic cell count. Efficient removal of strippings, use of oxytocin and/or injection of bovine somatotropin all act to restore yield during ODM. It is proposed that the mechanism of the yield loss is through changes in mammary function initiated by changes in cell shape during alveolar filling. Central to these changes is an increased permeability of the udder through impairment of tight junctions between the alveolar cells. This effect appears to be linked to a mild inflammatory response which occurs in the last 12 h of a 24-h period of milk accumulation. The ability to further reduce production losses on ODM could lead to much wider adoption of ODM. Key to this is the development of methods to identify high-producing animals tolerant of extended milking intervals.

Effect of temporary once-daily milking in early lactation on milk production and nutritional status of dairy cows

Chez 50 vaches Holstein (15 primipares), nous avons etudie l'effet de la traite temporaire une fois par jour, a partir du velage, sur la production laitiere et l'etat nutritionnel. Les vaches primipares ont ete reparties en deux lots: un lot temoin (Pc) trait en permanence 2 fois/j et un lot experimental (P3) trait une fois/j pendant les trois premieres semaines de lactation puis deux fois par jour. Les vaches multipares ont ete reparties en trois lots: un lot temoin (Mc) trait en permanence deux fois par jour ; un lot experimental trait une fois par jour pendant les trois premieres semaines de lactation puis deux fois par jour (lot M3) ; un autre lot experimental trait une fois par jour pendant les six premieres semaines de lactation puis deux fois par jour (lot M6). L'essai s'est termine a la fin de la periode hivernale. La traite une fois par jour n'a pas semble provoquer d'inconfort chez les vaches. Elle a diminue la production laitiere de 2,7 kg.j -1 en 1 re semaine de lactation, de 8,4 kg.j -1 en 3 e semaine, et de 14,5 kg.j -1 en 6 e semaine. Son effet n'a pas ete different entre les vaches primipares et multipares (p > 10 %). Des la premiere semaine de traite deux fois.j -1 , la production laitiere des vaches experimentales a augmente de 6,8 kg.j -1 (difference non significative entre les lots P3, M3 et M6). A partir de la semaine 7 la production laitiere des lots P3 et M3 a ete, en moyenne, plus faible que celle des lots Pc et Mc de 2,4 kg.j -1 en moyenne, et celle du lot M6 a ete plus faible que celle du lot Mc de 5,4 kg.j -1 en moyenne. Le taux proteique du lait des vaches traites une fois par jour a ete plus eleve que celui des vaches temoins, de 2,4 g.kg -1 pendant les periodes experimentale et post-experimentale. Le nombre de cellules somatiques dans le lait n'a pas ete significativement different entre les lots. Les vaches traites une fois.j -1 ont perdu moins d'etat corporel et moins de poids vif en debut de lactation que les vaches temoins, et elles ont presente un bilan energetique moins negatif ou plus positif (difference significative pour le lot M6). Le profil sanguin (teneurs en glucose, acides gras libres, 3-hydroxybutyrate) a atteste un meilleur equilibre energetique des vaches traites une fois par jour en debut de lactation. Cet essai suggere que les vaches fortes productrices supportent sans inconvenient apparent d'etre traites une fois par jour pendant le debut de la lactation et qu'il pourrait etre envisageable d'alimenter ces animaux avec des regimes plus pauvres en concentres que maintenant, sans accroissement des risques sanitaires.

Time course of milk accumulation-induced opening of mammary tight junctions, and blood clearance of milk components.

Eight cows in early lactation were used to study the effect of milk accumulation on the state of mammary tight junctions and to examine alpha-lactalbumin as an indicator of tight junction permeability in vivo. During three successive periods, the cows were milked twice (4 days), once (6 days), and twice daily (4 days). Plasma lactose, alpha-lactalbumin, and milk sodium concentrations were used as indicators of tight junction permeability. Furthermore, four cows were used to study the clearance of lactose and alpha-lactalbumin from the blood. Milk yield during once-daily milking decreased by 15.4% (P < 0.001). All indicators of mammary tight junction patency increased (P < 0.05) transiently during once-daily milking and indicated that tight junctions opened after approximately 18 h. Plasma alpha-lactalbumin and lactose were highly correlated (r = 0.82, P < 0.001), indicating the suitability of plasma alpha-lactalbumin as an indicator of tight junction status in vivo. Clearance of alpha-lactalbumin and lactose from the blood was best described by a biexponential model. Elimination half-lives for lactose and alpha-lactalbumin were 44 and 40 min, respectively. This study showed that milk stasis during early established lactation induces tight junctions to switch to a leaky state after approximately 18 h and to revert to the closed state shortly after milking.

Effect of milking frequency on milk somatic cell count characteristics and mammary secretory cell damage in cows

Abstract Objectives To examine whether once daily milking (ODM) increases somatic cell count (SCC) and causes changes in the proportion of macrophages, lymphocytes, or neutrophils in milk, and to examine whether ODM causes mammary secretory cell damage. Design During 3 successive periods, cows were milked twice daily (days 1 through 4), once daily (days 5 through 10), and twice daily (days 11 through 14); thus, each cow served as its own control. Milk samples were collected during each milking for SCC, bovine serum albumin (BSA; except days 1 and 14), and N-acetyl-β-D-glucosaminidase (NAGase) activity analyses. Differential cell counts were determined on days 2 (period 1), 5 and 8 (period 2), and 11 (period 3) in morning milk samples. Animals 8 multiparous Jersey cows. Procedures Cell counter (SCC), staining and counting (differential SCC), ELISA (BSA), and enzyme activity (NAGase). Results Once daily milking increased SCC (total and concentration), percentage of neutrophils, and BSA (content and total mass); during subsequent twice daily milking, SCC decreased, but BSA content and percentage of neutophils remained increased. Activity of NAGase was not affected by ODM. Conclusions ODM increases SCC, but this is not associated with damage to mammary secretory cells. The ODM-related sustained increase in BSA content coincided with an increase in neutrophil numbers, suggesting a causal relation. (Am J Vet Res 1996;57:902–905)

Effects of immunization against an autocrine inhibitor of milk secretion in lactating goats.

1. Lactating goats were immunized against the goat's milk protein identified as a feedback inhibitor of lactation (FIL). Immunization was by three treatments during the declining stage of lactation. 2. When antibodies to FIL were consistently detected in milk (in response to the third treatment), the rate of decline in milk secretion was significantly reduced compared with sham-immunized controls. Such a response was not apparent with the first two treatments when serum but not milk titres of anti-FIL were raised. 3. When one gland of immunized goats was switched (after the third immunization) from twice- to once-daily milking, the ipsilateral decrease in the rate of milk secretion was reduced significantly compared with sham-immunized goats. 4. The results are compatible with the hypothesis that the autocrine agent FIL acts during milk accumulation as an inhibitor of milk secretion.

Genotype X environment interactions in dairy cattle: a New Zealand perspective

AbstractIn recent genotype X environment studies between New Zealand and Canada, yields of fat and protein from Holstein Friesian (HF) cows were similar for daughters of sires from both countries, but Canadian daughters produced larger volumes of milk (6500 kg v. 3300 kg) and were taller. There was no interaction between the sire's national strain and the daughter's environment but there was a significant interaction between-individual sires within-strain and the daughter's environment so that the correlations between the sire proofs in the two countries were approximately half of the expected values.In New Zealand, milk production by cows of high or low genetic merit has been found to be affected similarly by differences in stocking rate, level of feeding and body condition at calving, providing no evidence of a large genotype X management interaction, although there is some evidence of an interaction between the effects of breed size and feeding, with smaller breeds being affected less severely by lower feeding level and clear evidence of genotype by milking management interactions. Over the past 40 years the need for pre-milking stimulation in New Zealand cows has been reduced or eliminated by inadvertent selection. Other recent evidence suggests that progress for genetic tolerance to once-daily milking may be possible.It can be concluded that interactions between group-average genotype and nutritional environment are not likely to have important effects on milk solid yields, at least within the HF breed, within the range of conditions normally found in temperate dairy systems, and provided that the environment is imposed from birth. However, there are likely to be significant interactions between the genotype of individual sires and environment and thus appropriate assessment and ranking of sires in each environment is essential.

Relationship between cisternal storage capacity and tolerance of once-daily milking in dairy cows

Once-daily milking reduces fixed costs, may be used strategically as a quota-management tool and could become the production system of choice in a programme of extensification. However, milk secretion is reduced during once-daily milking, through the action of an autocrine feedback inhibitor. This natural milk protein is active in milk stored within the secretory tissue, but not in cisternal milk (since it is then remote from its site of action). Consequently, large-cisterned cows should tolerate infrequent milking better than those with small cisterns, by virtue of storing a greater proportion of their milk in a site where the inhibitor is inactive. The aim of this experiment was to test this hypothesis.A group of 9 multiparous and 2 primiparous Friesian-Holstein cows from the Hannah herd calving in March and April 1991 were selected for study. All had been free of clinical mastitis during the current lactation. Throughout the experiment the group were managed routinely at grass as part of the main herd, and were fed a flat rate of 2.4 kg/d of an 18% protein concentrate feed. Normal milking was twice daily at 15:9 h intervals, and yield was recorded at each milking.

The response to thrice-daily milking and its relationship to cisternal storage capacity in dairy cows

Recently there has been increased interest in the effects of changing the milking frequency of dairy cows because of the possibilities of either increased milking frequency, through the use of robot-milkers or of once-daily milking as a part of a programme of extensification. Archer (1983), reviewing the literature and data from herds monitored by Farm Management Services, found milk yield responses on changing from twice- to thrice-daily milking from -0.14 to +0.49. These differences represent large between-animal differences in responses to thrice-daily milking and there is a need to identify sources of this variation.Milk is stored in the udder in both the cistern and the secretory alveolar tissue itself. Since milk contains a protein which is inhibitory to secretion, storage within the secretory tissue is disadvantageous and reduces the efficiency of secretory tissue. Work at the Hannah Research Institute has shown that the effect of the inhibitor can be overcome by milking more frequently and that the response to thrice-daily milking of goats was greater with animals having smaller cisterns.

Milk yield and mammary function in goats during and after once-daily milking

Starting in week 5 of lactation, goats were milked unilaterally once daily for 4 1/2 weeks, then twice daily for 12 weeks and finally thrice daily for 2 weeks. The control gland was milked twice daily throughout. During less frequent milking, yield fell by 26%. There was a rapid and essentially complete recovery of milk yield on resumption of twice-daily milking, and five of the six goats subsequently responded to thrice-daily milking with a small increase in milk yield. Mammary function was assessed during each phase by determining enzyme activities and in vitro synthesis rates of lactose and casein in mammary biopsies. There was a trend towards reduced differentiation of secretory cells during infrequent milking, with very little recovery during twice-daily milking but complete recovery during thrice-daily milking. The differentiative state of the control gland remained unchanged throughout.