Estimation of udder emptying based on milk constituents of strip samples after milking.

Milk ejection disorders were induced by oxytocin receptor blockade. We tested the hypothesis that the degree of udder emptying at incomplete milk ejection can be estimated based on the concentration of various milk constituents in different milk fraction samples. To induce different levels of spontaneous udder emptying (SUE) 10 Holstein dairy cows were milked either with or without i.v. injection of the oxytocin receptor blocking agent atosiban (ATO). In ATOearly, 12 µg/kg BW ATO was injected immediately before and in ATOlate directly after a 1 min manual udder preparation. The normal milking routine served as Control treatment. In all 3 treatments the udder was completely emptied by the i.v. injection of 10 IU oxytocin (OT) at the end of spontaneous milk flow. During all experimental milkings 4 milk samples were taken in all treatments: at the start of udder preparation (foremilk; FM), immediately after cessation of spontaneous milk flow and cluster detachment by hand stripping (strip milk; SM), from spontaneous removed milk in the bucket 1 (milk before OT; MBOT) and from the milk obtained after OT injection in the bucket 2 (milk after OT; MAOT). Fat, protein, lactose and electrolytes (Na, Cl and K) were measured in each milk sample. In addition, electrical conductivity (EC) was determined in parallel to continuous milk flow recording. The treatments induced individual degrees of SUE; therefore, the final evaluations of data were based on SUE classes instead of treatments. The most pronounced differences of milk constituents at different degrees of SUE were found for the milk fat content. The fat content of SM and MBOT remained almost unchanged up to 60% SUE, but was considerably higher if >80% of the milk was spontaneously removed. The concentrations of Na and Cl were highest and of K lowest if less than 20% on milk was received in the different samples. The EC was higher in SM and MBOT if <20% of milk was received. In conclusion, the blockade of the OT effect influences primarily the fat content, which confirmed an OT-induced fat secretion during milking. Similar effects are likely found in situations of disturbed milk ejections, caused by a lacking or reduced release of OT in response to different degrees of tactile udder stimulation. Our results show that the measurement of fat content and the EC in strip milk samples collected after cluster detachment can be used to estimate the completeness of udder emptying.

Stress indicators in dairy cows adapting to virtual fencing.

Virtual fencing (VF) enables livestock grazing without physical fences by conditioning animals to a virtual boundary delimited with an audio tone (AT) and an electric pulse (EP). The present study followed the adaptation process of lactating dairy cows to a VF system with changing virtual boundaries and investigated its impact on animal welfare. Twenty cows were divided into stratified groups (2× VF; 2× electric fencing, EF) of five individuals. Each group grazed half-days in a separate EF paddock of comparable size during 3 d of acclimation (P0), followed by 21, 14, 14, and 7 d of experimental treatment (P1 to P4). At the start of the trial, all cows were equipped with an IceQube pedometer (Peacock Technology Ltd, Stirling, UK) and a VF collar (Nofence AS, Batnfjordsøra, Norway). During P0, cows were accustomed to their first paddock with a deactivated virtual boundary and wearing the sensors. In P1 to P4, an active virtual boundary for the VF groups, and a second EF for the EF groups was set up parallel to an outer EF within their paddock. Throughout the trial, the sensors continuously tracked cow positions and activity behavior at 15-min intervals. From P1 onwards, the VF collars additionally recorded each AT and EP per cow with a georeferenced time stamp. During P0 to P4, daily feed intake, body weight, and milk yield were recorded in the barn. A total of 26 milk samples were collected per cow to determine milk cortisol levels. Behavioral observations were conducted for 2 h on day 23 to record agonistic behaviors, vocalizations, and excretions. The total number of stimuli per cow ranged from 37 to 225 ATs (mean ±â€…SD: 1.9 ±â€…3.3 per day) and 3 to 11 EPs (mean ±â€…SD: 0.1 ±â€…0.7 per day) throughout the trial. The maximum number of EPs per day was 8 for an individual cow and occurred once on D1. Mean EP/AT decreased by 55% during the first three half-days of grazing and with each paddock change from 0.2 EP/AT in week 1 to 0.03, 0.02, and 0 EP/AT in weeks 4, 6, and 8, respectively. Linear and generalized mixed effects models revealed that milk yield and cortisol, feed intake, body weight, and activity and lying behavior did not significantly differ between VF and EF groups. A higher number of agonistic behaviors were observed in the VF groups when the VF system was activated. However, due to the short observation periods only few contacts were observed in total. Overall, all cows adapted to the VF system without evidence of lasting adverse effects on animal welfare.

Virtual fences are commercially available but face restrictions in some countries due to animal welfare concerns. For virtual fencing (VF), animals are equipped with collars that emit audio tones (ATs) followed by electric pulses (EPs) when they cross a virtual boundary tracked by global navigation. Existing studies have so far not covered the aspect of longer-term learning, impacting possibly VF suitability. The present study followed therefore the learning process of dairy cows with changing virtual boundaries and examined behavior and stress indicators in dairy cows during an 8-wk adaptation to VF across four experimental periods. Four control and treatment groups of five cows each were investigated. EPs occurred most frequently on days 1 to 3 and remained low for the remaining experiment. In the latter two experimental periods, almost no EPs were recorded while ATs were still triggered, indicating that it took the animals two introductions to a new fence line to respond to the ATs only. Animal welfare was assessed by monitoring cow activity and lying behavior, milk yield, milk cortisol, feed intake, body weight, and frequencies of agonistic interactions, vocalizations, and excretions. All cows adapted to the VF system without compromising animal welfare during the study period.

The mouthpiece chamber vacuum pattern indicates the cessation of milk flow and suits as an indicator to reduce teat end vacuum at a quarter level.

We investigated the suitability of the quarter mouthpiece chamber vacuum (MPCV) as an indicator for cessation of quarter milk flow to potentially adjust the teat end vacuum at a quarter level. We tested the hypothesis that a MPCV increase is a clear indicator of quarter milk flow cessation. In addition, we tested if a quarter-individual vacuum reduction at MPCV increase reduces the mechanical effect on the teat. Ten dairy cows were milked twice daily with a quarter-specific vacuum supply with continuously high (51 kPa; TRT51) or low vacuum setting (41 kPa; TRT41), or high vacuum setting combined with a quarter-specific vacuum reduction by 10 kPa immediately after the quarter-specific MPCV increase (TRT51/41). Whole udder milk flow was continuously recorded. Each treatment was repeated at 4 subsequent milkings. The high vacuum settings (TRT51; TRT51/41) reached higher values in peak flow rate and average milk flow and consequently shorter machine-on time. The time from start of milking until the steep increase of the MPCV was shorter in front than rear quarters, and hence the time from start of MPCV increase until end of milking was longer in front than rear teats. Teat condition of the right front teats was measured for teat wall diameter by ultrasound and teat tissue thickness by cutimeter at 5 and 20 min after each experimental milking. The teat measurements were taken at the teat tip (distal barrel) and 2 cm above the teat tip (proximal barrel). The proximal teat wall diameter tended to be higher in TRT51 than in TRT41, both 5 and 20 min after milking. The distal teat wall diameter at 5 min was greater in TRT51 than in TRT41. In TRT51/41 the teat wall diameter at both locations was intermediate, not significantly different from either TRT51 or TRT41. The distal teat tissue thickness was greater in TRT51 than in TRT41, and tended to be greater in TRT51/41 than in TRT41 at 5 min. The proximal teat tissue thickness at 5 min was higher in TRT51 and TRT51/41 than in TRT41. The teat tissue thickness decreased from 5 to 20 min only in the proximal barrel. The quarter-individual MPCV increase appears to be a suitable indicator of the cessation of milk flow. The lack of a significant reduction of mechanical effect on the teat by a reduced vacuum of 41 kPa indicates that the vacuum level chosen may be still too high under conditions of a separate vacuum supply for each quarter, which prevents a vacuum drop caused by the whole udder milk flow.

Efficacy of oral administration of specific immunoglobulins in preventing neonatal calf diarrhoea in dairy herds.

BACKGROUND: The aim of this study was to evaluate the efficacy of bovine concentrated lactoserum (BCL) containing specific immunoglobulin G against Escherichia coli, rotavirus and coronavirus in preventing neonatal calf diarrhoea (NCD). METHODS: A total of 489 newborn calves from 35 herds were orally given either BCL or a placebo before the first feeding of colostrum and clinically supervised by the farmers for the first 14 days of life. The diarrhoea score was defined according to the following criteria: 0 = no diarrhoea; 1 = light diarrhoea without medical treatment; 2 = diarrhoea requiring oral treatment (rehydration and/or antibiotic therapy); and 3 = severe diarrhoea requiring parenteral rehydration or resulting in death. RESULTS: A total of 138 calves suffered from diarrhoea (28%), and 65 (13%) showed signs of diarrhoea requiring treatment. The odds of getting NCD were reduced (odds ratio = 0.326; p < 0.001) in the BCL group. There was a tendency towards a reduction in the duration of NCD in the BCL group (2.25 (±1.7) days vs. 2.88 (±2.7) days in the placebo group) (p = 0.052). Furthermore, no calves died in the BCL group, whereas four calves died in the placebo group. LIMITATIONS: Because of the design of the study using animals in practice, the mechanisms explaining the clinical findings remain as hypotheses. Diarrhoea scoring performed by farmers has to be analysed and interpreted with caution. CONCLUSIONS: This study demonstrates that BCL as a single preventive treatment is effective in reducing the incidence of NCD even in a region with good general management of dairy calves and overall good colostrum quality.

Effect of voluntary waiting period on metabolism of dairy cows during different phases of the lactation.

An extended calving interval (CInt) by extending the voluntary waiting period (VWP) could be associated with altered metabolism in dairy cows. The aim of this study was first to evaluate the effects of VWP on metabolism and body condition during the first 305 d after the first calving in the experiment (calving 1), around the end of the VWP, and during pregnancy (280 d before calving 2). Second, the effects of the VWP on metabolism were determined from 2 wk before until 6 wk after calving 2. Third, individual cow characteristics were used to predict milk production and body condition of cows after different VWP. Holstein-Friesian cows (N = 154, 41 primiparous [PP], 113 multiparous [MP]) were blocked for parity, milk production, and lactation persistency, randomly assigned to a VWP of 50, 125, or 200 d (VWP50, VWP125, or VWP200) and followed from calving 1 until 6 wk after calving 2. In the first 6 wk after calving 1 and from 2 wk before until 6 wk after calving 2, weekly plasma samples were analyzed for nonesterified fatty acids (NEFA), ß-hydroxybutyrate, glucose, insulin, and insulin-like growth factor 1 (IGF-1). From wk 7 after calving 1 until 2 wk before calving 2, insulin and IGF-1 were analyzed every 2 wk. Fat- and protein-corrected milk (FPCM) and body weight (BW) gain were measured weekly. Cows were divided in two parity classes based on calving 1 (PP and MP) and remained in these classes after calving 2. During pregnancy, MP cows in VWP200 had greater plasma insulin and IGF-1 concentration and lower FPCM compared with MP cows in VWP125 (insulin: 18.5 vs. 13.9 µU/mL, CI 13.0-19.7, P < 0.01; IGF-1: 198.5 vs. 175.3 ng/mL ± 5.3, P = 0.04; FPCM: 22.6 vs. 30.0 kg/d ± 0.8, P < 0.01) or VWP50 (insulin: 15.8 µU/mL, P < 0.01; IGF-1: 178.2 ng/mL, P < 0.01; FPCM: 26.6 kg/d, P < 0.01) and had a greater daily BW gain compared with cows in VWP50 (3.6 vs. 2.5 kg/d ± 0.2; P < 0.01). After calving 2, MP cows in VWP200 had greater plasma NEFA concentration (0.41 mmol/liter) compared with MP cows in VWP125 (0.30 mmol/liter, P = 0.04) or VWP50 (0.26 mmol/liter, P < 0.01). For PP cows, the VWP did not affect FPCM or body condition during the first lactation in the experiment, or metabolism after calving 2. Independent of the VWP, higher milk production and lower body condition before insemination were associated with higher milk production and lower body condition at the end of the lactation. Variation in these characteristics among cows could call for an individual approach for an extended VWP.

Extending the voluntary waiting period (VWP) reduces the frequency of calvings. This may benefit cow health but includes the risk of fattening and low milk yield at the end of the lactation. The aim of this study was to evaluate the effects of the VWP on metabolism and body condition during different phases of the lactation and start of the next lactation. Moreover, individual cow characteristics in early lactation were used to predict milk production and body condition of cows after different VWP. An extended VWP did not affect milk production or metabolism of primiparous cows. Multiparous cows with an extended VWP had a greater plasma insulin concentration and a lower milk production around the end of the VWP and during pregnancy, and a greater body condition during pregnancy. A higher milk production and a lower body condition before successful insemination were associated with a higher milk production and a lower body condition at the end of the lactation. Therefore, selecting multiparous cows with a higher milk production and a lower body condition for an extended lactation may reduce the risk of fattening and low milk production at the end of the lactation, while still having the benefit of a reduced frequency of calvings.

Endocrine changes during the peripartal period related to colostrogenesis in mammalian species.

This review discusses endocrine and functional changes during the transition from late gestation to lactation that are related to the production of colostrum in different mammalian species. Species covered in this article include ungulate species (cattle, sheep, goats, pigs, horses), rodents (rat, mouse), rabbits, and carnivores (cats, dogs), as well as humans. An immediate availability of high quality colostrum for the newborn after birth is crucial in species where a transfer of immunoglobulins (Ig) does not or only partially occur via the placenta during pregnancy. Declining activity of gestagens, in most species progesterone (P4), is crucial at the end of pregnancy to allow for the characteristic endocrine changes to initiate parturition and lactation, but the endocrine regulation of colostrogenesis is negligible. Both, the functional pathways and the timing of gestagen withdrawal differ considerably among mammalian species. In species with a sustaining corpus luteum throughout the entire pregnancy (cattle, goat, pig, cat, dog, rabbit, mouse, and rat), a prostaglandin F2α (PGF2α)-induced luteolysis shortly before parturition is assumed to be the key event to initiate parturition as well as lactogenesis. In species where the gestagen production is taken over by the placenta during the course of gestation (e.g., sheep, horse, and human), the reduction of gestagen activity is more complex, as PGF2α does not affect placental gestagen production. In sheep the steroid hormone synthesis is directed away from P4 towards estradiol-17ß (E2) to achieve a low gestagen activity at high E2 concentrations. In humans the uterus becomes insensitive to P4, as parturition occurs despite still high P4 concentrations. However, lactogenesis is not completed as long as P4 concentration is high. Early colostrum and thus Ig intake for immune protection is not needed for the human newborn which allows a delayed onset of copious milk secretion for days until the placenta expulsion causes the P4 drop. Like humans, horses do not need low gestagen concentrations for successful parturition. However, newborn foals need immediate immune protection through Ig intake with colostrum. This requires the start of lactogenesis before parturition which is not fully clarified. The knowledge of the endocrine changes and related pathways to control the key events integrating the processes of colostrogenesis, parturition, and start of lactation are incomplete in many species.

This manuscript reviews and compares hormonal and functional changes occurring in the conceptus (embryo and its extra-embryonic membranes) and their effects on the mammary gland during development from pregnancy to colostrum formation and milk production in multiple mammalian species. Declining activity of gestagens at the end of pregnancy is crucial to allow for both parturition and onset of milk production in most mammals. Strategies to achieve this state of low gestagen activity are different among species. In species where the corpus luteum is sustained throughout the entire pregnancy, luteolysis is the key event to initiate parturition and onset of milk secretion (cattle, goat, pig, cat, dog, rat, mouse, rabbit). However, in species where the placenta takes over gestagen production during the course of pregnancy, the achievement of a state of low gestagen activity is more complex. It ranges from redirection of the hormone production pathway away from gestagens in sheep, to decreasing sensitivity of the uterus towards gestagens in humans. In the horse, there is evidence pointing towards redirection of the hormone production as well as a decrease in sensitivity towards gestagens, but the exact mechanisms are still not clarified.

Effects of feeding level, milking frequency, and single injection of cabergoline on blood metabolites, hormones, and minerals around dry-off in dairy cows.

This study aimed to investigate the effect of the different dry-off strategies based on reducing feeding level (normal vs. reduced energy density), reducing milking frequency (twice vs. once daily), and administration of a dopamine agonist after last milking (i.e. saline vs. cabergoline injection) on blood metabolites, hormones, and minerals around dry-off. In this experiment, 119 Holstein dairy cows were used in a 2 × 2 × 2 factorial arrangement. In the last week before dry-off, cows were allocated to 1 of the 4 possible dry-off strategies based on feeding level and milking frequency. Within 3 h after last milking, cows were injected with either saline or a D2 dopamine agonist (cabergoline; Velactis, Ceva Santé Animale, Libourne, France; labeled for use only with abrupt dry-off, e.g., no preceding reduction in feeding level or milking frequency before last milking). After dry-off, all cows were fed the same dry cow diet and data collection continued for a week. Blood samples were collected from the coccygeal vein on d -9, -6, -5, -2, 1, 2, 5, and 7 relative to dry-off. Additionally, blood was sampled at 0, 3, and 6 h relative to injection of either cabergoline or saline, equivalent to d 0.125, 0.250, and 0.375 relative to last milking (dry-off). The reduced feeding level before dry-off caused reduced glucose and insulin concentrations as well as increased free fatty acid concentrations, particularly when reduced feeding level was combined with milking the cows 2× daily. The intramuscular injection of cabergoline caused the expected reduction in circulating prolactin concentrations. In addition, dopamine-agonist cabergoline induced an atypical simultaneous pattern of plasma metabolites (i.e., increased glucose and free fatty acid concentrations), hormones (i.e., reduced insulin and increased cortisol concentrations), and minerals (i.e., reduced calcium concentration), indicating that normal metabolic and mineral homeostatic regulations were hindered after the injection of ergot alkaloid cabergoline. In conclusion, reducing milking frequency seems the best management strategy to reduce milk production at dry-off among those tested in this study.

The interplay of continuous milk ejection and milking system with and without prestimulation at different vacuum settings.

Efficient machine milking requires an optimal interaction of alveolar milk ejection in the udder and milk removal by the milking machine. The aim of the present study was to test whether the equilibrium between continuous milk ejection and milk removal can also be maintained at very fast milking through a particularly high vacuum. Eight Holstein dairy cows were milked at 42, 52, or 60 kPa, with (PS) or without (nPS) prestimulation. Each of the 6 treatments was conducted at 2 afternoon milkings in each animal. The prestimulation lasted 40 s and consisted of forestripping and teat cleaning. The cluster attachment followed after a 20-s latency period. Throughout each milking, B-mode ultrasound videos of the gland cistern of 1 front quarter as well as milk flow and claw vacuum curves were recorded. Total milk yield was neither affected by nPS or PS nor by the vacuum level. Milk removed within the first minute and the first 2 min of milking and average milk flow were higher, and the duration of incline and time until peak milk flow were shorter at PS than at nPS milkings at all vacuum levels. Machine-on time was shorter at PS than at nPS milkings, although only at 42 and 52 kPa vacuum, obviously caused by the high percentage of bimodalities occurring in nPS milkings (17% bimodalities in PS vs. 92% bimodalities in nPS milkings). The frequency of bimodalities was higher at high than at low vacuum both in PS and nPS milkings. Peak flow rate and average milk flow were both higher at higher vacuum levels. The duration of milk flow plateau was shorter at 60 kPa than at 42 kPa milkings. At the highest vacuum (60 kPa), the shorter plateau phase indicated a declining milk ejection rate toward the end of the plateau phase, and milk ejection could no longer keep up with the fast milk removal; hence, a higher milking efficiency at a higher vacuum level could only be achieved as long as the gland cistern remained sufficiently filled by the continuous milk ejection. The ultrasound imaging confirmed this finding as the duration of cisternal area plateau in the recorded front quarter was shorter at high than at low vacuum. Thus, the highest vacuum of 60 kPa did not cause a shorter machine-on time than 52 kPa. In conclusion, milking at a very high vacuum can increase milking efficiency compared with a low vacuum. However, a vacuum reduction at the start and toward the end of milking is required to prevent overmilking if milking is performed at a very high vacuum.

Effects of different nutrient supply on metabolism and mammary immune response to an LPS challenge in early lactation of dairy cows.

Energy and nutrient deficiency in dairy cows in early lactation is considered to contribute to their increased susceptibility to mastitis. We have tested the hypothesis that feeding diets with high contents of either nitrogenic, glucogenic, or lipogenic components in early lactation affects both the endocrine and metabolic status, as well as the mammary immune competence. After calving, cows were fed increasing amounts of concentrate up to 10 kg/d rich in crude protein (nitrogenic, n = 10), glucogenic precursors (glucogenic, n = 11), or lipids (lipogenic, n = 11). In wk 3, one udder quarter was challenged with lipopolysaccharide (LPS) from Escherichia coli. Blood and milk were sampled on the day before LPS challenge (d -1), and on d 0, 1, 2, 3, and 9 after LPS challenge. On the day of LPS challenge additional samples were taken hourly for quarter milk and every 3 h for blood. Urea concentrations were higher in plasma and milk of cows fed the nitrogenic diet. However, plasma concentrations of glucose, cholesterol, triglycerides, ß-hydroxybutyrate, nonesterified fatty acids, as well as insulin, glucagon, and insulin-like growth factor-1 were not affected by the different diets. The mammary immune challenge induced a substantial increase of somatic cell count (SCC) in the treated quarter, and a transient decrease of total milk yield and white blood cells similar in all diet groups for one day. The absolute phagocytosis of blood leukocytes was decreased; however, the phagocytosis per cell was increased in glucogenic-fed cows at 6 h after LPS challenge. During mammary inflammation an insulin resistance, shown by increased plasma glucose, insulin, and glucagon, developed similarly in all diet groups. ß-hydroxybutyrate and nonesterified fatty acids were decreased at 1 d after LPS challenge in glucogenic-fed cows only. Cholesterol did not change, and triglycerides only decreased significantly in lipogenic-fed cows 6 h after challenge. On d 9 after LPS challenge, SCC and milk yield and metabolic factors were recovered in all groups. In conclusion, the endocrine and metabolic situation, and the immune response to intramammary LPS of dairy cows during early lactation was not substantially influenced by the elevated supply of nitrogenic, glucogenic, or lipogenic components due to the provided feed in this study.

Drying-off practices on Swiss dairy farms: Status quo and adoption potential of integrating incomplete milking.

Drying-off practices to reduce milk production before dry-off are gaining attention because high milk yields at dry-off are becoming more common and increase the risk to cow health and welfare during the dry period. Incomplete milking for the last days before dry-off is one approach for reducing milk production. We conducted an online survey to determine the currently used drying-off practices on Swiss dairy farms and to identify the adoption potential of integrating incomplete milking before dry-off. In March 2021, the online survey was sent to a representative sample of 1,974 Swiss dairy farmers. A total of 518 completed questionnaires were analyzed. The mean number of dairy cows per farm was 39 (range: 11-140 cows). Thirty-five percent of cows produced considerable quantities of milk (>15 kg/d) at dry-off, and milk yield at dry-off increased with increasing annual milk yield. Abrupt dry-off was applied on 45% of the farms. The participants reported observing behavioral changes of cows such as increased vocalizations and decreased lying time associated with dry-off. Selective dry cow therapy was applied on 74% of the farms, and 44% of the participants indicated the use of antibiotics at dry-off as being "rather often," "often," or "always." Correlation analysis revealed that with increasing annual milk yields, the frequency of observed behavioral changes and antibiotic use at dry-off increased as well. Therefore, drying-off approaches that reduce milk production while supporting cow welfare are needed. We found that farmers showed an interest in testing the presented drying-off approach of incomplete milking. In addition, the farmers indicated that they would be more willing to test incomplete milking before dry-off if it became available for automated use in milking parlors or robots. Uncertainties regarding udder health appeared to be the main barrier for the adoption potential of this approach.

Implications of placentation type on species-specific colostrum properties in mammals.

Maternal care is essential to optimally support survival of the offspring. During evolution of mammalian species, different phenotypes have evolved in relation to gestation length, number, size, and maturation stage of the offspring at parturition, as well as colostrum and milk composition. The aim of the present review is to describe relationships between placental function and colostrum and milk composition in different mammalian species. Species covered in this article include humans, rabbits, rodents (rat and mouse), carnivores (cats and dogs), and a variety of ungulate species (cattle, sheep, goats, pigs, and horses). Species-specific aspects are elucidated with a special focus on the transfer of passive immunity. In this regard, the structure and thus the capability of the placenta to transport immunoglobulins from maternal to fetal circulation in utero dictates the necessity of the passive transfer of immunity via colostrum. Consequently, species with exclusive postpartal transfer of immunity such as in all ungulate species have greater immunoglobulin G concentrations in colostrum than species with a prepartal transfer in utero, where especially immunoglobulin A with its local immune function in the gastrointestinal tract is present in colostrum (e.g., rabbit and human). In terms of the nutritional purpose, suckling frequency is an important factor determining the gross composition of colostrum as well as in the mature milk of these species. Milk of nidicolous animals with long intervals in-between suckling events contains more fat than milk of nidifugous animals with constant access to their mother. However, the importance of colostrum and milk consumption for newborn animals and human babies goes beyond nutrition and the transfer of immunity. Numerous bioactive components such as growth factors, hormones, and oligosaccharides are enriched in colostrum and transition milk, which support the development of the intestinal tract and local immune system.

During evolution of mammalians, intrinsic strategies and components of maternal care during the transition from pregnancy to lactation have evolved into a broad variety in gestation length, number, size, and maturation stage of the offspring at parturition, and colostrum and milk composition. The original purpose of immuno-protective glandular secretions is still conserved in many mammalian species, where colostrum, that is, the very first milk obtained after parturition, contains the greatest amounts of immunoglobulins, leukocytes, lysozyme, lactoferrin, oligosaccharides, etc. Apart from its nutritive function, bioactive components in colostrum and milk support the development of gastrointestinal structures and intestinal microflora. Depending on the placentation type and intrauterine transfer of immunoglobulins, the survival of the neonate depends more or less on the passive transfer of immunoglobulins via colostrum. The aim of the present review is to describe relationships between placenta function and colostrum (and milk, respectively) composition in different mammalian species. Special attention is paid to the transfer of passive immunity from the dam to the offspring.

The teat cup detachment level affects milking performance in an automatic milking system with teat cleaning and milking in the same teat cup.

The goal of the present study was to determine the best quarter milk flow for teat cup detachment depending on lactational stage and milking interval to optimize the milking process in automatic milking systems (AMS). Milking characteristics and post-milking teat condition were recorded in an AMS with all actions from teat cleaning to post-milking teat dipping occurring in the same teat cup and liner (GEA DairyRobot R9500). In 24 dairy cows, 12 in early (<80 DIM) and 12 in late lactation (>180 DIM), 294 milkings were recorded during 12 consecutive days. Teat cup detachment was set at a quarter milk flow of 50, 87.5 or 125 g/min. Voluntary milking intervals varied similarly in cows in early (6.1-14.8 h) and late lactation (6.3-15.7 h). Total milk yield, milk production per h and average milk flow were higher in early than in late lactation cows. Total milk yield per milking did not differ between detachment levels. The mean milking time was reduced by up to 1.5 min at the highest compared to the lowest detachment level mainly in early lactation cows (P < 0.05). However, no significant effect of the detachment level on milking time was observed at milking intervals >10 h. Average milk flow was higher at milking intervals >10 h than ≤10 h (P < 0.05). In the early lactation cows (only) the average milk flow increased with higher detachment levels (P < 0.05). Teat condition did not differ among detachment settings or milking intervals. In conclusion, teat cup detachment up to 125 g/min reduces milking time in both early and late lactation without a loss of milk yield or affecting the teat condition. Combined with a higher average milk flow through avoiding too short milking intervals, the total milking time and hence stall occupancy can be optimized by early teat cup detachment.

Effect of Type of Cow-Calf Contact on Health, Blood Parameters, and Performance of Dairy Cows and Calves.

Prolonged cow-calf contact (CCC) could potentially improve dairy calf welfare. However, it is currently unknown how different types of CCC affect animals' biological functions. We evaluated health and performance parameters of dairy calves and their dams, where calves: (i) had no contact with their dam (NC), in which the calf was removed from the dam directly after birth (n = 10); (ii) were allowed to have partial contact (PC) with their dam, in which the calf was housed in a calf pen adjacent to the cow area allowing physical contact on the initiative of the dam but no suckling (n = 18); (iii) were allowed to have full contact (FC) with their dam, including suckling, in which calves were housed together with their dams in a free-stall barn (n = 20). Throughout the first 7 weeks postpartum, data were collected on the health status, fecal microbiota, hematological profile, immune and hormonal parameters, and growth rates of calves, and on the health status, metabolic responses, and performance of dams. Overall, FC calves had more health issues (P = 0.02) and a tendency for higher antibiotic usage (P = 0.07) than NC calves. Additionally, FC calves showed elevated levels of erythrocytes, hematocrit, hemoglobin, and leukocytes on day 49 compared to NC calves (P < 0.001). Calf fecal microbiota changed over time, and we found preliminary evidence that fecal microbiota is affected by the type of CCC, as reflected by differences in relative abundances of taxa including Lactobacillus in FC calves compared to NC and PC calves except on days 7 and 66. The FC calves had a greater average daily gain in body weight than NC and PC calves (P = 0.002). Cow health was not affected by the type of CCC, although in the first 7 weeks of lactation FC cows had a lower machine-gained milk yield accompanied by a lower fat percentage than NC and PC cows (P < 0.001). These results indicate that full contact posed a challenge for calf health, presumably because the housing conditions of FC calves in this experimental context were suboptimal. Secondly, ad libitum suckling leads to higher weight gains and negatively affected milk fat content besides machine-gained yields. More research into strategies to improve cow-calf housing and management in CCC systems is warranted.

Feeding and Manual Brushing Influence the Release of Oxytocin, ACTH and Cortisol Differently During Milking in Dairy Cows.

Aim: This study aimed to examine the effects of feeding or abdominal brushing on the release of the hormones oxytocin, ACTH and cortisol during milking in dairy cows. Methods: Twelve cows in early lactation were used (2 × 2 factorial experimental design), testing the effects of two types of sensory stimulation during milking over a 3 day period; feeding concentrate or manual abdominal brushing (1 stroke/s). Blood samples for hormone analyses were collected at time at -15, -1, 0 (onset of cluster), every min for 8 min, at 10, 12, 14, 16, 30, and 60 min. Hormone levels were assayed and AUC was calculated. Results: Milking was associated with an immediate and significant rise of oxytocin. When milking was combined with feeding, significantly higher levels of oxytocin were observed at 2 and 4 mins (p < 0.05). No effect of brushing on oxytocin levels was observed. Milking alone was associated with a significant rise of ACTH levels. Feeding in connection with milking reduced the immediate rise of ACTH levels (p < 0.05) and AUC (p < 0.02), whereas no effects of brushing were found. Milking caused a progressive rise of cortisol levels. Concomitant feeding did not influence cortisol levels, whereas brushing significantly decreased cortisol levels at 1, 5 and 14 mins after onset of milking (p < 0.05). Conclusion: Feeding increases oxytocin release in response to milking and decreases ACTH levels. Abdominal brushing did not influence these variables, but decreased cortisol levels. These data demonstrate that activation of afferent vagal nerve fibres and of cutaneous sensory nerves originating from the abdominal skin in front of the udder influence milking related hormone release differently.

Effects of short and long milking intervals on milking characteristics and changes of milk constituents during the course of milking in crossbred Istrian × Awassi × East-Friesian ewes.

The main objective of this experiment was to evaluate the effects of two milking intervals (8 and 16 h) on milk constituents (fat, protein, lactose, dry matter, and log10 SCC) of nineteen Istrian × Awassi × East-Friesian crossbred ewes in different milk fractions (0-25, 25-50, 50-75 and 75-100%) during the course of milking and in machine stripping (MS) milk. Furthermore, we sought to determine the effect of the two milking intervals on milking characteristics (average milk flow rate, peak milk flow rate, machine-on time, total milk yield, and milk production rate) and whether each milk constituent within each milking interval is best described by a linear, quadratic, or cubic function. Average milk flow rate and milk yield per milking decreased in the 8 h milking interval compared to the 16 h milking interval (P < 0.05). Peak milk flow rate, machine-on time, and milk production rate were not different between the two milking intervals. Overall, milk fat content, dry matter content, and log10 SCC increased in the 8 h milking interval compared to the 16 h milking interval (P < 0.05). Milk protein content did not change through the main milk fractions at either milking interval. Milk lactose content did not change through the milk fractions at the 8 h milking interval, whereas it decreased in the 75-100% and stripping milk fractions at the 16 h milking interval (P < 0.05). The 0-25% and stripping milk fractions contained the highest log10 SCC compared to all other milk fractions (P < 0.05). Changes of milk fat and dry matter content throughout milking were best described by quadratic functions, whereas milk protein content, milk lactose content, and log10 SCC were best described by different functions depending on the milking interval. These results demonstrate that milking interval influenced all milk constituents in various milk fractions during the course of ewe milking. Moreover, milking characteristics such as average milk flow and total milk yield, and the appropriate mathematical function to characterize milk constituents throughout a milking, were affected by milking interval.

Inhibition of lipopolysaccharide-induced suppression of luteal function in isolated perfused bovine ovaries.

Recently, we observed that lipopolysaccharide (LPS) suppresses corpus luteum (CL) function in isolated perfused ovaries. It remained unclear if this suppression was due to increased luteal PGF2α secretion or LPS-induced apoptosis. Therefore, possible impacts of PGF2α and LPS were inhibited by a non-steroidal anti-inflammatory drug (flunixin) and an endotoxin-binding agent (polymyxin B), respectively. Bovine ovaries with a mid-cycle CL were collected immediately after slaughter and perfused for 240 min. After 50 min of equilibration, either flunixin or polymyxin B (5 µg/ml of each) were added to the perfusion medium of six ovaries, respectively. All ovaries (n = 12) were treated with E. coli LPS (0.5 µg/ml) 60 min after the onset of perfusion, and received 500 I.U. of hCG after 210 min of perfusion. Progesterone and PGF2α were measured in the effluent perfusate every 10 and 30 min, respectively. Biopsies of the CL were collected every 60 min to determine the mRNA expression of the cytokine TNFA and factors of apoptosis (CASP3, -8). Flunixin-treatment inhibited the increase of PGF2α after LPS-challenge that was observed in the polymyxin B-treated (PX-LPS) ovaries. After hCG-stimulation, progesterone secretion increased (P < 0.05) in group PX-LPS but not in the flunixin-treated (F-LPS) ovaries. Compared to initial values before LPS-challenge, luteal mRNA expression of TNFA and CASP3 was increased (P < 0.05) in group F-LPS at 120 and 180 min, respectively, and those of CASP8 was decreased (P < 0.05) in PX-LPS at 60 and 120 min after LPS-treatment. In conclusion, although flunixin managed to inhibit PGF2α, it did not suffice to successfully prevent LPS-induced apoptosis. However, endotoxin-binding polymyxin B resulted in luteal responsiveness to hCG after LPS-challenge.

Reduced liner-open phase and vacuum instead of prestimulation increase parlor efficiency in dairy cows.

Adequate prestimulation is considered a requirement for a fast, gentle, and complete udder emptying at machine milking. Reduced vacuum or reduced liner-open phase of pulsation (or both) may replace prestimulation and consequently reduce work load of the milker and increase parlor efficiency. In the present study we compared 2 milking routines (MR) with manual prestimulation (LPrep = long preparation: 15 s of forestripping, teat cleaning, and stimulation; SPrep = short preparation: 5 s of teat cleaning) followed by 1-min latency period and milking at standard vacuum and pulsation settings (claw vacuum 44 kPa, pulsation rate 60 cycles/min, pulsation ratio 65/35) with 2 MR consisting of 5 s of teat cleaning, immediate cluster attachment and milking at reduced vacuum with or without shortened liner-open phase of pulsation until milk flow exceeded 400 g/min (RP = reduced pulsation: pulsation ratio 30/70, pulsation rate 50 cycles/min, claw vacuum 44 kPa; RPV = reduced pulsation and vacuum: pulsation ratio 30/70, pulsation rate 50 cycles/min, claw vacuum 34 kPa). Cluster detachment was performed at 400 g/min in all MR. Ten Holstein dairy cows were milked twice daily at 14-h and 10-h milking intervals. Milk flow and electrical conductivity (EC) were recorded throughout milking. During the first 2 min of each milking ultrasound cross-section images of the gland cistern of one front quarter were recorded, and 5 min after the end of milking teat tissue thickness of both front teats was measured by using a cutimeter. Most milking characteristics such as total milk yield, average milk flow, and machine-on time reached higher values at 14-h than 10-h milking intervals, but did not differ among MR. However, the occupancy time (time from the first touch of the udder until cluster detachment) was considerably shorter in RP and RPV compared with LPrep and SPrep. Ultrasound cross section areas of the gland cistern were larger in LPrep than in RP and RPV indicating that milk ejection already occurred at cluster attachment in LPrep. This assumption is also supported by the lower EC at cluster attachment in LPrep than in RP and RPV, which was caused by the presence of alveolar milk in the gland cistern after milk ejection. The MR RP and RPV increase parlor efficiency and are work-saving alternatives to MR, which include an adequate prestimulation (LPrep). However, shortening prestimulation to a 5-s teat cleaning followed by a latency period and milking at regular vacuum and pulsation is not adequate to save occupancy time. Because milking was performed at a relatively low vacuum (44 kPa) and at a detachment level of 400 g/min, teat tissue thickness did not differ among MR, and the vacuum reduction in RPV did not cause an additional advantage for teat condition compared with RP.

Moderate Differences in Plasma Leptin in Mares Have no Effect on Either the Amino Acid or the Fatty Acid Composition of the Uterine Fluid.

Female mammalian reproductive functions are closely linked to body condition and metabolic status. Energy homeostasis is regulated by endocrine hormones such as insulin, IGF-I, leptin, and adiponectin via the hypothalamic-pituitary-adrenal axis. These metabolic hormones and their receptors are also expressed in reproductive tissues and the embryo. We investigated the relationship between circulating leptin and the fatty acid (FA) and amino acid (AA) composition of the equine uterine fluid (UF) and peripheral blood plasma (BP) by using a mass spectrometry-based approach. UF and BP were collected from ten broodmares on days 6 and 7 post ovulation, respectively. The mares were retrospectively assigned to two groups according to their BP leptin concentrations (high leptin [> 1.6 ng/mL] versus low leptin [<0.8 ng/mL]). Specific AA and FA compositions for BP and UF were found with different levels of respective metabolite abundances. The main FAs in BP were stearic, palmitic and linoleic acid. In UF, the three most abundant FAs were eicosapentaenoic, arachidonic and stearic acid. The AA profile of BP was dominated by glycine, glutamine, serine and alanine, which were likewise among the highly abundant AAs in UF. In UF, glutamic acid had by far the highest concentration. Therefore, BP leptin concentration within a physiological range does not seem to affect the specific FA nor the AA composition of the UF. The composition of the UF may therefore be mediated by local rather than by peripheral metabolic hormones.

Amino acids activate mTORC1 to release roe deer embryos from decelerated proliferation during diapause.

Embryonic diapause in mammals leads to a reversible developmental arrest. While completely halted in many species, European roe deer (Capreolus capreolus) embryos display a continuous deceleration of proliferation. During a 4-mo period, the cell doubling time is 2 to 3 wk. During this period, the preimplantation blastocyst reaches a diameter of 4 mm, after which it resumes a fast developmental pace to subsequently implant. The mechanisms regulating this notable deceleration and reacceleration upon developmental resumption are unclear. We propose that amino acids of maternal origin drive the embryonic developmental pace. A pronounced change in the abundance of uterine fluid mTORC1-activating amino acids coincided with an increase in embryonic mTORC1 activity prior to the resumption of development. Concurrently, genes related to the glycolytic and phosphate pentose pathway, the TCA cycle, and one carbon metabolism were up-regulated. Furthermore, the uterine luminal epithelial transcriptome indicated increased estradiol-17ß signaling, which likely regulates the endometrial secretions adapting to the embryonic needs. While mTORC1 was predicted to be inactive during diapause, the residual embryonic mTORC2 activity may indicate its involvement in maintaining the low yet continuous proliferation rate during diapause. Collectively, we emphasize the role of nutrient signaling in preimplantation embryo development. We propose selective mTORC1 inhibition via uterine catecholestrogens and let-7 as a mechanism regulating slow stem cell cycle progression.