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Small ruminants not only differ on mammary gland anatomy, milk's properties and the amount of milk yielded comparable to those of dairy cattle, but also on the milking routine strategies and machine milking settings to maximize daily milk secretion. The udder compartment is proportionally larger in dairy sheep and goats, which requires modifications in the milking machine settings, milking procedures and allows the use of different milking strategies as they better tolerate extension of milking intervals. Depending on the breed, cisternal milk in goats varies from 70% to 90%, whereas in dairy sheep it varies from 50% to 78% of the total gland capacity. This explains why these species are commonly milked without pre-milking teat preparation, while in goats it is applied only in cases of high prevalence of intramammary infection in the herd. Recent French researchers observed that 40% of the goats presented an unbalanced udder as well as unbalanced morphology (21% to 30%) and functional milk flow (around 10% to 20% more) which could induce overmilking. In dairy sheep, selection for higher milk production increases teat angle insertion. Thus, to increase machine milk fraction, it is recommended to use either the 'Sagi hook' as an alternative for lifting up the 'pendulous' udder during milking or to perform machine stripping. There are three cluster removal strategies for small ruminants: manual, timed and milk flow driven automatic cluster removal (ACR). Automatic cluster removal reduces overmilking, improves teat condition, enables labour saving and provides a consistent milking routine in small ruminants. There are three to five main milk flow profiles in ewes and goats, which result in curves with one or two peaks (or plateau) and different patterns of the milk flow decreasing phase due to the degree of mammary gland imbalance and teat characteristics. When taking into account our current knowledge, ACR recommended take-off settings for goats are: 200 g/min+10 s delay time (DT) for a long decreasing phase or two plateau curves and 500 g/min+5 s DT for a short decreasing phase and one plateau curve. The ACR take-off settings for ewes are: 150 g/min +10 s DT for long decreasing phase and 200 g /min+5 s DT for a short decreasing phase. This review is intended to be useful for scientists and producers seeking basic knowledge of milking routines and cluster detachment settings for parlour performance and milk quality.

Friendly interactions between humans and animals such as gentling or petting have been shown to have positive behavioural and physiological consequences in many species. In primates, rodents and dogs, oxytocin has been associated with tactile contact and anti-stress effects that may influence bonding and responses to stress situations. However the activation of the oxytocinergic system in other human-animal interactions such as with herbivores, had not yet been studied. Sixteen female lambs were reared by artificial feeding reinforced with 3× 30 s daily stroking sessions. At 6 weeks of age, the test consisted in measuring first plasma oxytocin and cortisol responses in lambs during a first 6-min phase in the home pen where the familiar caregiver gently stroked the lamb, and then physiological and behavioural responses in a test pen during a 20-min - phase of social isolation followed by a 20-min - phase of reunion with its familiar caregiver. The lambs expressed behavioural agitation during the whole period of isolation. A strong affiliative response towards the human and a sustained reduction of the agitation behaviour were observed during reunion. Lambs' behaviours when isolated and when in contact with the human were correlated suggesting a response to social separation from the familiar caregiver more than to social isolation from congeners. No significant changes in cortisol levels were observed during the test. Oxytocin levels did not vary during human contact, but increased when the familiar caregiver left the lamb alone in the test pen. In conclusion, lambs displayed affiliative responses towards their caregiver, and the lack of cortisol response during isolation while oxytocin was released suggest an anti-stress effect of oxytocin., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Two experiments were designed to determine if melatonin concentrations differ between jugular veins. In a first experiment, blood was collected continuously every 30 min from each jugular during 12-h from 6 ewes. In a second experiment, 100 ewes were sampled twice at night simultaneously from the two jugular veins. In both experiments, mean melatonin concentrations were similar between right and left jugulars. However, within individuals, large differences were observed between the two sides (p<0.001). This difference was stable over time and the higher side varies among individuals. The concentrations of prolactin and oxytocin, measured in the same samples did not show such differences. This observation raises the question of the origin of this phenomenon. Moreover, it has important implications for studies in which melatonin concentrations need to be assessed accurately. Indeed, a reliable quantitative assessment of melatonin production by the pineal gland requires sampling from both jugular veins., (Copyright 2009 Elsevier Ltd. All rights reserved.)

This paper aims to compare different adaptive responses of the mammary gland of cows, ewes, and goats submitted to extended milking intervals in different systems of management. Depending on the species, these extended milking intervals can be characterized by the following milk removal approaches; 3 milkings every 2 d, elimination of 1 milking per week (i.e., 13 vs. 14 milkings per week), and once-daily milking with additional suckling (i.e., dual purpose system of suckling and milking) or without suckling (exclusive once-daily milking). All the high-yielding animals and breeds adapted without problems to being submitted to intervals between milking less than 20 to 21 h. Under these conditions, all ruminant species demonstrated only low and transitory variations in milk production and quality. Thus, management systems using such an interval are good tools for the dairy producer who wants to save time without important adverse economic impact. When animals have good mammary gland health, these management systems can be applied without preliminary adaptation. However, goats and some breeds of dairy ewes seem to adapt to once-daily milking better than cows. Additionally, goats and ewes with higher production levels demonstrate a lower reduction in milk yield. With goats, there is only a limited variation in milk quality and cheese-making capacity of the milk produced, but ewes and cows show a significant enrichment of milk constituents, especially in fat. This indicates some differences in the regulation of lactose, protein, and fat synthesis depending on the duration of the milking interval and provides interesting models for physiological studies on milk secretion and synthesis regulation. Anatomical and physiological characteristics of lactating cows and ewes, in terms of cisternal vs. alveolar volumes within the mammary glands, could contribute to different abilities in adaptation to different milking systems. In goats, however, other mechanisms, such as compliancy of the mammary gland and regulation of tight junction impermeability, could be involved in milk secretion regulation and, thus, could become new targets for genetic selection of animals better adapted to accept extended milking intervals.

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

The objective was to compare in the ewe the effects of easy and difficult procedures for artificial insemination (AI) (as related to rapid or poor accessibility of the cervix, respectively) on plasma cortisol (CORT) and oxytocin (OT), and uterine motility. All AI were simulated using a catheter empty of semen to study genital and environmental stimuli only. In experiment 1, 40 ewes were sampled after Al, and whether it was an easy or difficult procedure was reported for each animal. While CORT concentrations rose to a similar amount in all ewes, whatever the Al procedure, a significant OT response occurred after a difficult procedure only (n = 18) (17.4 +/- 1.7 versus 12.7 +/- 0.7 pg x mL(-1) before Al, p < 0.05). In experiment 2, uterine activity was monitored in 4 ewes using an implantable telemetric transmitter equipped with an intrauterine pressure catheter. An increased uterine activity occurred during 2 +/- 1 min after an easy Al (n = 5), whereas the evoked activity lasted for 15 +/- 4 min after a difficult Al (p < 0.001, n = 7). A similar long-lasting response occurred after OT administration (100 mIU, i.v.). We concluded that the increase in uterine motility after a difficult Al resulted from a reflex release of OT, and not to a "stress" effect.

The potential luteal effects on milk production were examined in dairy ewes that were not superovulated in contrast to studies using superovulated ewes. Lactating East Friesian crossbred ewes (n = 24) were synchronized using intravaginal progesterone (controlled intravaginal drug-releasing device), PGF2alpha, and gonadotropins. After ovulation, corpora lutea (CL) were counted via laparoscopy on d 4 and 11. On d 5, ewes received either saline (CLYES, n = 12) or PGF2alpha (CLNO, n = 12) to allow CL persistence (2.4 +/- 0.3 CL on d 11) or regression (0 CL on d 11), respectively. Each ewe received two CIDR d 5 to 18 to maintain high concentrations of plasma progesterone (P4) and to suppress estradiol (E2). Each ewe received PGF2alpha on d 18. Data were collected during three periods (pretreatment: d 0 to 5; treatment: d 6 to 18; posttreatment: d 19 to 25). Milk yield and milking time were recorded daily, milk samples were obtained for analyses of fat and protein, and blood samples were collected for P4 and E2 immunoassay. During treatment, CLYES ewes had higher milk yield (1.56 vs. 1.44 +/- 0.01 kg/d), milk fat (92.2 vs. 81.1 +/- 1.3 g/d), and milk protein (83.7 vs. 77.5 +/- 0.8 g/d) compared with CLNO ewes, respectively. Differences were maintained posttreatment, despite luteolysis in CLYES ewes. Estradiol concentrations did not differ between treatments and were low after d 5. Milk production was increased in East Friesian ewes in the presence of an average of 2.4 corpora lutea, an effect independent of estradiol.

Milk yield and plasma oxytocin (OT), prolactin (PRL), and cortisol (CORT) during suckling and machine milking were measured in multiparous ewes subjected to a mixed management system of 3 sucklings and two daily milkings. Peak hormones were significantly increased and were similar during suckling and milking for PRL (181 vs. 163.3 ng x mL(-1)) and CORT (12.5 vs. 11.5 ng x mL(-1)). During the period of exclusive suckling, OT was always significantly released (90.3 pg x mL(-1)); however, during the period of mixed management, OT concentrations only increased during suckling compared to milking (91.7 vs. 13.1 pg x mL(-1)). The mean volume of milk obtained during suckling (632 mL) was significantly higher than during milking (255 mL). Thus, during a mixed management system, oxytocin and prolactin releases are not under similar central regulation. A mixed system, without OT release during milking, does not contribute to accelerate the conditioning of ewes for machine milking.

The aim of this work was to investigate whether luteal oxytocin released after non-luteolytic prostaglandin F2 alpha (PGF2 alpha) challenge could explain the intramammary pressure (IMP) rises previously described in pregnant ewes after the normal life span of a corpus luteum. Blood oxytocin levels and IMP after challenge were measured in cycling and pregnant lactating ewes until the response ceased (approximately 55 d post oestrus). Oxytocin release was not significantly different for cycling and pregnant ewes, and fell to its lowest levels on days 16-18 post oestrus in both groups, i.e. with or without luteolysis. However, although IMP response fell with luteolysis in cycling ewes, the response persisted until day 55 in pregnant ewes. This lack of correlation between oxytocin release and IMP response raised interesting questions including: is there an unknown oxytocic compound that can be released after PGF2 alpha stimulation of the corpora lutea?

This experiment was conducted in 59 Lacaune breed ewes in order to compare milk production and milk distribution between alveolar and cisternal storage after superovulation. After a corpora lutea (CL)-free control period, the ewes were superovulated by different treatments (experimental period) and 5 classes were differentiated according to the number of corpora lutea observed (0, 1, 2, 3 to 6 and > 6 CL respectively (group A (n = 20), B (n = 7), C (n = 14), D (n = 7), E (n = 11)). Our results showed a positive correlation between the number of corpora lutea and the oxytocin and progesterone levels in plasma, total milk production and cisternal volume, and a negative correlation with alveolar volume. The milk production at the evening milking for groups A and E (388.6 and 384.8 ml respectively during the control period) respectively reached 321.7 ml (-17.2%) and 413.4 ml (+7.4%) during the experimental period; ie, a 24.6% difference between these 2 extreme groups. These results could likely be explained by oxytocin levels reaching those obtained during milking and by the effect of milk transfer from the alveolar to the cisternal lumen. Additionally, progesterone could act directly on milk synthesis at the level of the secretory cells.

In four ewes direction of propagation of uterine contractions was evaluated using an electromyographic technique during 15 entire estrous periods; 120,101 propagations were analyzed. When horns were considered separately 89.9% of all propagations were classified into three main modes: ascending (34.3%), descending (59.85%), and divergent (5.85%). When both horns were analyzed simultaneously, horn's synchronicity was observed in most instances; on this basis, eight modes of propagation were identified of which three accounted for two-thirds of all propagation: synchronous descending (24.9%), reciprocal propagation (descending on one horn and then ascending on contralateral horn) (22.1%), and isolated descending propagation (18.0%). A time-dependent pattern of propagation throughout estrus was clearly identified, the percentage of ascending propagations reaching a minimum (16.5%) and the percentage of descending propagation reaching a maximum (77%) at peak uterine motility level. By considering both direction of uterine propagation and cervical mechanical activity, a new hypothesis concerning two aspects of sperm transport (speed and mechanism) was formulated. It is hypothesized that the high prevalence of descending propagations is important to reduce sperm cell population by selecting the most vigorous spermatozoa; such selection is possible when the mechanical cervical activity is low or absent (cervix open); when cervical mechanical activity is high (cervix closed), it is suggested that both descending and ascending propagations participate in sperm transport by back and forth motion of luminal fluid within the uterine lumen.

Relationships among sleep, feeding behavior, posture, and GH secretion were investigated in two groups of ruminant lambs in January (n = 6) and May (n = 3). Lambs were placed in individual cages and fed ad libitum. Behavioral features were obtained from continuous polygraphic recording. Blood was collected from undisturbed sheep every 3 min for 24 h via an indwelling catheter connected to a peristaltic pump. One month after the sampling session, ovine GH (oGH) was iv administered to evaluate oGH kinetic parameters. From GH plasma concentrations and oGH kinetic parameters, the instantaneous secretion rate of GH was reconstituted using a numerical deconvolution method. All lambs exhibited normal behavioral patterns. The clearance of oGH was similar for the two groups, and the daily production rates of GH were estimated at 14.60 +/- 7.99 micrograms/kg.24 h in January and 10.57 +/- 5.21 micrograms/kg.24 h in May. Analysis of concentration profiles indicate an episodic pattern of GH secretion into plasma. The mean number of peaks was 16.22 +/- 4.47/24 h, and the mean duration was 47.2 +/- 12.8 min for the nine sheep. When instantaneous secretion rates were taken into account, the number of identified peaks was similar, but the mean duration was reduced (32.9 +/- 9.8 min for the nine sheep). Significant relationships were not found between GH plasma concentration profiles and the state of vigilance, food behavior, or posture. Conversely, when the instantaneous secretion rates were taken into account, the highest GH production rate was detected during rest, i.e. slow wave sleep and rapid eye movement sleep, absence of food intake or rumination, and lying down. It is emphasized that the use of GH instantaneous secretion rate instead of GH concentration is of importance when evaluating the relationships between GH dynamics and short duration events. It is concluded that the influence of vigilance on GH secretion, which has already been demonstrated in humans, is likely to exist in other species.

The oxytocic effect of a prostaglandin F2 alpha analogue, fenprostalene, was assessed in 4 ovariectomized ewes fitted with electrodes in both uterine horns and in the cervix. In the absence of estradiol priming, significant motility changes were not elicited by fenprostalene. Conversely, when ewes were primed with 17-beta-estradiol, fenprostalene markedly increased the electrical activity in the uterus and cervix. After a single subcutaneous fenprostalene administration (5 micrograms/kg), activity values remained about twice that of the control values during 8.52 +/- 3.31 hours. When the same dosage was administered IM, similar post-injection activity values were obtained, but only during 5.88 +/- 0.72 hours. Oxytocic effects of fenprostalene were far longer than those elicited by a single IM administration of 50 micrograms of prostaglandin F2 alpha (tham salt)/kg (0.91 +/- 0.32 hours) or by a single IM administration of 1 microgram of cloprostenol/kg (1.88 +/- 0.81 hours). Using the dose-effect relationship curve obtained from the same ewes by continuous IV infusions of oxytocin (OXT), the postinjection activity values reached after a single subcutaneous administration of fenprostalene were equivalent to those of an IV infusion of OXT at an average dose of 4.09 ImU of OXT/kg/hr for 6 to 13 hours, according to the values of the particular ewe concerned. These long-lasting oxytocic properties, in addition to its luteolytic capabilities, would make fenprostalene a suitable drug for promoting effective evacuation of the uterus when required in daily veterinary practice.

Review of the Sicilo-Sarda dairy sheep micro-sector in Tunisia: current situation and prospects for the recovery of the Sicilo-Sarda breed. Introduction. The Sicilo-Sarda is the only Tunisian dairy sheep breed. Milk from this breed is used in a micro-sector of cheese production. Numbers of sheep from this breed fell significantly during the 1990s, due to unfavorable economic and political choices, as well as a lack of technical control of livestock, which risked the sustainability of this cheese production sector. However, initiatives to preserve this breed have taken place in recent years. The present review of the scientific and professional literature highlights the current knowledge of the sheep dairy sector in Tunisia and presents the actions currently under way or to be undertaken in favor of its safeguarding. Literature. The Sicilo-Sarda breed shows low levels of milk production but this can be improved even in extensive systems. Breeding (suckling/weaning/milking) and reproductive management needs to be reviewed in order to increase milk production. Similarly, the breed's genetic pathway needs to be mobilized through the establishment of a selection scheme based on farm phenotypes of interest (quantity and quality of milk, mammary morphology) and/or the introduction of Sardinian blood via artificial insemination. Conclusions. A renewed interest in the Sicilo-Sarda breed in Tunisia has been noted since 2005 through a reorganization of the sector, giving new dynamism to the profession. Significant margins of progress have been highlighted, both in terms of animals and breeders. The downstream sector of this milk chain must also help create a better identification of the products and the "terroir" of production for consumers. This will create new opportunities to develop this micro-sector to ensure its sustainability.