Alternatives to hormonal treatments (HT) in dairy sheep reproduction management are being explored in response to increasing societal concerns regarding animal welfare and food safety. However, hormone-free reproduction implies higher variability in flock performances and additional constraints for timely synchronised artificial insemination (AI) in the flock, impacting the diffusion of genetic progress. The use of the male effect, a well-known practice to induce synchronised oestrus, combined with precision tools (e.g., heat detector), is a plausible way to implement AI without HT in dairy sheep farms. To date, the consequences of such alternative reproduction management on the whole farm sustainability remain unknown. To anticipate these potential impacts, a multi-agent model (REPRIN’OV) was used to simulate dairy sheep farm’s sustainability indicators (biotechnical, economic, environmental and workload). A reproduction management scenario, including the use of the male effect followed by AI on the adult ewes (HFAI), was simulated and compared to the current reproduction management of four case study farms (Early_conv, Late_conv, Early_org and Late_org). They were selected to represent the different agricultural models (Conventional or Organic) and reproduction seasons (Early -during spring, out of ewes’ natural reproduction season - or Late -from early summer to the end of autumn) of the Roquefort Basin’s farms in Southern France. Simulation results showed that the HFAI scenario had different consequences depending on the farm’s production system type. A negative effect on most key sustainability indicators of the Conv farms was observed, as a significant reduction in the fertility rate, in the proportion of young ewes born from AI (-54 % in both farms; P<0.05) and in the flock’s milk production were observed; while the workload and greenhouse gas (GHG) emissions were increased compared to the initial scenario. In the Org farms, HFAI had neutral to positive effects on most indicators as the fertility, milk production of the flock, workload during milking and GHG emissions were barely affected by this scenario, while an increase in the proportion of young ewes born from AI was observed (+39% and +43% in each farm respectively; P<0.05), allowing a better farm gross margin. Still, the workload during lambing was increased in Early_org (+18%; P<0.05), as Early farms, tended to be more negatively impacted by HFAI than Late ones. Overall, our simulation approach provides interesting elements to exchange with stakeholders on how to progress toward a socially acceptable reproduction management system, for the dairy sheep sector.

Hormone-free (HF) reproduction in dairy sheep is a way to meet current societal demands, but it requires being prepared for collateral impacts on related system components. The efficiency of HF practices (e.g., using the male effect for estrus induction and synchronization) is uncertain compared with hormonal treatment (HT). For example, these practices can lead to higher variability in the flock physiological stage patterns throughout the year, which has direct consequences for feeding regimens. The objective of this work was to simulate the impacts of HF reproduction management, including artificial insemination (AI), on the temporal distribution of productive performance and nutritional requirements of a conventional dairy sheep flock. Using the REPROsheep2.0 model, 6 scenarios were compared over one typical production season for the same flock (n = 597 Lacaune ewes) intensively reared in the Roquefort region of France. These scenarios depicted reproduction with HT and AI in mid-May (Early); HT and AI in July (Summer Late); HT and AI in November (Autumn Late); and their HF versions (HF-Early; HF-Summer Late, and HF-Autumn Late, respectively). In all HF scenarios, a reduction in the number of ewes lambing and consequently in the annual milk production of the farm was observed (-1 to -7%). This affected annual performance with a subsequent decrease of total annual nutritional requirements (-2 to -6%). The HF scenarios resulted in a staggering of lambing events with a 7- to 14-d shift in the appearance of milk production peaks and related nutritional requirements compared with the HT scenarios. Transitioning from conventional to HF reproduction management, while preserving AI, would increase farm workload, lengthen milking period operations, and necessitate a readjustment of feeding management strategies with regard to available feed resources. Depending on the production season, the observed delay in the distribution of nutritional requirements could be either an attractive or an unfavorable outcome for farmers. The delay may be concordant, for example, with the recently observed impacts of climate change on seasonal forage availability in Mediterranean regions (less spring herbage production and warmer temperatures) that are affecting farmers' decision-making about the most efficient use of forage and feed resources.

Livestock production systems are strongly influenced by societal constraints which induce changes in their overall chain value organization. In dairy sheep farming, practices such as the male effect (ME) supported by new precision tools (heat detector) can be used to stop the use of hormonal treatments (HT) for heat induction and synchronization. However, the effectiveness of these "hormone-free" (HF) methods for managing ewes' reproduction remains more uncertain than that of HT. Thus, introduction of HF practices in farms currently managed with HT could imply collateral impacts on the overall functioning of the production system and affect its longterm sustainability. In this work, a new multi-agent model (called REPRIN'OV) was designed to simulate consequences of introducing a HF reproduction management on a series of biotechnical, economic and environmental farm performance indicators, including farmer workload. Three reproduction management scenarios were simulated over five consecutive years for the case study of a French dairy sheep farm considered as conventional (i.e. using HT for reproduction management). They were defined as: use of HTs and insemination (HAI); no use of HTs while preserving insemination practice (HFAI); no use of HTs and direct mating only (i.e., no insemination; HFM). Results confirm that implementing HF reproductive management without accompanying it with further changes in farm management, could negatively impact several indicators of the farm sustainability in the medium and long-term. Indeed, the HF scenarios resulted in overall lower farm biotechnical performances (e.g., -4% for the fertility rate; P < 0.05) due to a more variable heat induction. An increase in farmer's workload during the lambing period (+34% and +33% of h/L of milk in HFAI and HFM, respectively; P < 0.05) was also observed, mainly due to more staggered lambing periods. As for the simulated environmental indicators, they were increased, mostly due to the reduction of the total milk production in HF's (e.g., +6% of farm methane emissions per L of milk for both HFAI and HFM; P < 0.05). Nevertheless, positive outcomes were also simulated in the HFs as ewes lambing peaks were lower than in HAI suggesting, e.g., a possibility to improve ewes and lamb surveillance during lambing. HF scenarios also led to higher gross margin (GM) per litre of milk produced because no HT was used, reducing the production costs compare to HAI. In addition, implementing insemination in HFAI improved farm milk production and quality (i.e., fat and protein content), which resulted in improved total GM compared to HFM. Still, the reduction in the total milk production in HFs was too important compared with the improvement of the GM per litre, resulting in a reduced total GM in these scenarios (-4% and -5% in HFAI and HFM, respectively; P < 0.05). Overall, simulation results showed that to warrant sustainable introduction of HF strategies (including ME), new frameworks in the organization of key operations at the farm level should be explored (e.g., extending reproduction or milking periods length) and trade-offs should be discussed, considering all involved stakeholders of the dairy sheep industry and the chain's value requirements. The REPRIN'OV model, may provide an effective tool to simulate the collateral impacts of establishing HF reproductive management and could be used as a decision support system to accompany the ambitious transition towards a HF dairy sheep industry in Europe and beyond.

The male effect is an effective natural technique to induce off-season ovulation and ultimately mating or artificial insemination in small ruminants. It constitutes an alternative to hormonal treatments in conventional breeding systems and, to shift and organise the yearly production cycle, is currently the only solution complying with European organic standards. However, its associated performances are still heterogeneous, both in terms of the global response and the extent of reproductive synchronisation of the females, due to complex interactions with environmental factors that limit its use on commercial farms. This study was carried out on a French organic farm under commercial conditions to investigate, in the field and across five consecutive years, the main parameters affecting the early ovarian response to a ram effect on Lacaune dairy ewes. While the within-year binary logistic regressions yielded contrasting results, the cross-year mixed-effect binary logistic regression models clearly showed that parameters associated with the nutritional state of the animals have a profound influence on the ovarian response of the ewes. Indeed, the probabilities of a spontaneous resumption of ovarian activity before the ram effect and of an early ovarian response to the ram effect were positively associated with the body condition score, total milk production and the age of the animals, while being negatively associated with the milk production level at the 3rd milk recording. The probabilities of a spontaneous resumption of ovarian activity before the ram effect were positively associated with the interval between lambing and the introduction of the rams. Altogether, these results indicate that the ovarian performances in response to a male effect follow a bell-curve pattern with optimal performances depending upon a complex combination between photoperiodic and nutritional cues. Regarding these latter, this study highlights the major contribution of body reserves and energy balance dynamics.

Managing reproduction of a dairy sheep flock without using hormones for oestrus induction and synchronisation is an alternative method that complies with agroecological principles, animal welfare and public health concerns. However, shifting from conventional reproductive management to a hormone-free philosophy means leaving more room for individual intraflock variability in oestrus occurrence. The success of establishing alternative hormone-free reproduction systems relies on managing the variability of ewes' individual responses, which are themselves influenced by individual characteristics. Therefore, the so-called REPROsheep model was built to study the effects of individual ewes' characteristics, such as age, body condition score (BCS) or milk yield, on individual responses, as well as the overall productive and reproductive performances of the flock. This dynamic agent-based model (ABM) represents individual reproduction and lactation processes in a hormone-free management context. Outputs at the flock level were simulated using this model. Two dynamic outputs (weekly number of ewes lambing and weekly milk yield) and two punctual outputs (total number of ewes lambing and total milk yield) were simulated. Sensitivity analysis showed that the studied outputs were affected by ewe age, pre-mating BCS and milk-yield distributions in the flock. Increasing average age or pre-mating BCS by 0.5 from a starting point of 2.5 and average milk-yield by 50 L from a starting point of 195 L appeared to increase, for one breeding season, the number of ewes lambing, the concentration of those lambing events over one period, as well as total milk yield, whereas decreasing the average value of these factors by the same amount appeared to produce the opposite effect. Management strategies favouring an optimum age and pre-mating BCS, as well as good milk yield for the individuals of the flock, may thus be a lever for optimising performance, especially lambing distribution over time. Therefore, the REPROsheep model seems relevant to determine how a management strategy (affecting flock structure in terms of age, body condition or production potential) can impact the performance of a dairy sheep flock in the context of hormone-free reproduction.

Shortage and refeeding situations lead to switches in metabolic pathways induced by undernutrition and body energy reserve (BR) replenishment cycles. In a 122-d experiment, 36 adult Merinos d'Arles ewes were chosen and first accustomed to diet ingredients (i.e., wheat straw, pelleted alfalfa and sugar beet pulp) and the facility environment for 22 d. Then, ewes were randomly assigned to one of three "diet challenge" treatments during 50 d, (control, underfed and overfed; 12 ewes each) corresponding to 100%, 70% or 160% of energy requirements allowances, respectively. Then, a "refeeding challenge" was applied the last 50 d (i.e., diets adjusted with the same ingredients). An individual monitoring of body weight (BW), body condition score (BCS) and energy metabolism was carried out. The last day, a "ß-adrenergic challenge" was applied. Anabolic or catabolic responses were accompanied by synchronized metabolic regulations, leading to contrasting metabolic and BR profiles. Average BW and BCS were higher and lower in overfed and underfed ewes, respectively, which was proportional to lower and higher BR mobilization dynamics. Higher plasma free fatty acids (FFA) were accompanied by lower blood insulin, leptin and glucose levels. After refeeding, a rebound in BW and BCS were observed, and FFA were drastically reduced in underfed ewes. No differences were detected in plasma FFA at the end of the study, but the lipolytic activity was different and contrasted with the adipose tissue mass.

Background In order to maintain homeostasis, ruminants submitted to alternating shortage and refeeding situations manifest switches in metabolic pathways induced by undernutrition and body reserves ( BR ) replenishment cycles. The objective of this experiment was to study adaptive regulatory mechanisms present during subsequent feeding transition periods and the inherent lipolytic activity of the adipose tissue in individuals with contrasted BR. Three diets containing different levels of energy were offered to 36 mature, dry, non-pregnant Mérinos d’Arles ewes in an experiment lasting 122 days. Ewes were selected with similar body weight ( BW ), body condition score ( BCS ) and were allocated into three equivalent treatments according to the plane of nutrition: normally fed ( Control ); underfed ( Under ) or overfed ( Over ). The BW, BCS and individual energy metabolism were monitored. At the end of the experiment, lipolytic activity of adipose tissue was studied through a ß-adrenergic challenge to the same ewes, with body conditions according to the offered diet ( Normal, Leans and Fat , respectively). Results Anabolic or catabolic responses to energy dietary manipulation were accompanied by synchronised metabolic regulation, leading to contrasting metabolic and BR profiles. Average BW and BCS were higher and lower in Over and Under ewes, respectively. The higher and lower BR variations were observed for Under and Over ewes. Higher plasma non-esterified fatty acids ( NEFA ) concentrations were accompanied by lower insulin, leptin and glucose. Differences in leptin were consistent with the dietary energy load (Over > Control > Under). After refeeding, a rebound in BW and BCS was observed for the three groups whereas NEFA was drastically reduced in Under ewes. No differences among treatments were detected in NEFA profiles at the end of the study but lipolytic activity responses to the ß - adrenergic challenge were different and coherent with the adipose tissue mass (Fat > Normal > Lean) and, importantly, was also different between ewes from the same group or BR status, thus evidencing diversity among individual adaptive capacities. Conclusions The ability of ewes to quickly overcome undernutrition situations by efficiently using their BR was confirmed. There is potential for a simplified ß-adrenergic challenge protocol helping to identify differences in adaptive capacity among individuals.

An experiment was conducted to observe the oestrous behaviour in ewes through an automated oestrus detection system. Five mature adult Merino male rams, equipped with an electronic detector (Alpha-D), were included with a total of 60 ewes from the same breed. The libido of the males was assessed as the number and frequency of mounts. The accepted mountings by ewes were recorded by an electronic identifier worn by the female. In the first synchronized oestrus (C1), the ewes were exposed to rams wearing an anti-mating apron. In the following spontaneous cycle (C2), all the rams were allowed to mate. In the third cycle (C3) and the fourth cycle (C4), the rams were assumed to detect ewes in oestrus (open ewes). After the exclusion of isolated readings, the mean interval from sponge withdrawal to onset of oestrus was 31 +/- 11 h and duration of oestrus in C1 C3 was 22 +/- 18,16 +/- 11 and 16 +/- 8 h, respectively. The libido differed widely among the rams and cycles number with an average number of mounts per ram in C1-C4, that were 213,322, 85 and 3 respectively. It is concluded that all the females were correctly detected and the assessed libido of males was repeated. (C) 2017 Elsevier B.V. All rights reserved.

To evaluate the effects of nutrition on the sexual behaviour of ewes, forty-eight mature (7.61 +/- 1.9 years old) Merino d'Arles ewes with an average initial body condition score (BCS = 2.26 +/- 0.23) and similar body weight (BW = 46.6 +/- 13.8 kg) were fed three contrasting diets for three months. The diets provided varying levels of energy expressed as proportion of Maintenance Energy Requirements (i.e. Low= 70%MER; Medium =113%MER and High = 180%MER) with the ultimate objective of obtaining different BW and BCS. Blood samples were taken before and at the end of the three-month experimental period to measure plasma metabolites (glucose, GLU; beta-Hydroxybutyrate, beta OHB; non-esterified fatty acids, NEFA) and hormones (insulin, INS and leptin, LEPT). The ewes' sexual behaviour, e.g. attractiveness, receptivity and proceptivity, was estimated through normalized pen-tests before and at the end of the experiment after hormonally-induced oestrus. As expected, the dietary treatments induced significant changes in BW (i.e. the final weights were 38.6 +/- 2.5, 47.3 +/- 3.6 and 55.0 +/- 2.2 kg for Low, Medium and High groups, respectively) and BCS (1.33 +/- 0.4, 1.90 +/- 0.2 and 2.33 +/- 0.2 for Low, Medium and High, respectively). The metabolic and hormonal changes were in agreement with the known effects of feeding regimes.The sexual behaviours of ewes were only partially changed by feeding regimes. While the scores of receptivity (SR) of ewes to males (i.e. number of agonistic interactions with the courting ram) and scores of proceptivity (SP) towards rams (i.e. time spent close to a pen with rams) remained unchanged (P> 0.05), there were significant (P< 0.001) changes (Low= 2.42; Medium =3.63 and High = 4.47; P< 0.001) in their scores of attractiveness (SA: i.e. a higher score is given to the preferred ewes by rams). This SA was well correlated with the BW (r= +0.83; P<0.0001) and BCS (r = +0.73; P<0.0001) of ewes, it was also negatively correlated with metabolites (NEFA: r= -0.32; P <0.05) and positively with anabolic hormones (INS: r= +0.42; P<0.01). Combining these variables, the SA is clearly explained (R-2 = 0.79; P<0.0001; n =36) by a model including the static (long-term) effects of nutrition (BW and BCS) and the dynamic effects of nutrition (NEFA and INS). This work demonstrates that the nutritional status of female sheep, during oestrus, produces efficient cues that clearly orient males in their mating choices. (C) 2017 Elsevier B.V. All rights reserved.

We investigated if sexual behaviour of rams can be assessed with an electronic Alpha-Detector (AD) which automatically records mounts of mating rams. To evaluate the rams’ libido (i.e. all sexual activities), we used six intact and six vasectomised rams in pen tests in three different seasons (late spring, autumn and early spring). The pen tests consisted of 30-min visual observations of each ram placed in a group of six Merino ewes (three ewes in oestrus and three ewes not in oestrus). In the pen tests, sexual behaviour was recorded and divided into two categories: pre-copulatory and copulatory. For validation purposes, during the pen tests the 12 rams were equipped with the AD and the number of times the 18 oestrous ewes were mounted were counted over a period of 3 days. Of the 1191 mounts visually identified in the six 30-min sessions, 1026 were recorded automatically by the AD (i.e. 94%). The paddock test is an automated method consisting of the same rams wearing an AD and placed in a flock of ~250 Merino ewes on two occasions (late spring (spring 1) and early spring of the following year (spring 2)), their copulatory activities were automatically recorded over a 5-day period. The results of the pen tests in the three seasons revealed no difference between the two types of rams (breeding v. detecting rams). Based on live observations high correlations (r=+0.81, P<0.003 for breeding and r=+0.76, P<0.02 for detecting rams) were found between pre-copulatory and copulatory behaviours. The libido of the two types of rams measured in pen tests showed high repeatability across the three seasons (83 and 75%, P<0.05 for copulatory and pre-copulatory behaviours, respectively). When measured automatically in paddock tests over two consecutive springs, even higher repeatability was observed in both breeding (94%; P<0.01) and detecting rams (97%; P<0.004) in the number of mounts. In addition, high correlations (+0.89<r<+0.94) between copulatory behaviours, as measured by live observations, and those measured by the AD were obtained. The automatic measurement of ram libido in paddock tests appears to be more reliable than pen tests and far less time consuming. We therefore recommend this automated method to estimate the libido of rams. In addition, this method can be used at any season of the year provided that ewes in oestrus are present in the flock.

The objective of this work is to determine the efficiency of the electronic oestrus detection system Alpha Detector (AD) in sheep. Males are equipped with a harness carrying the electronic device. This original system consists of a custom RFID reader which is triggered at the time of mounting to read the transponder that is placed on the females' rump. This detector stores the ID number of ewe together with date and time of each mount. Two trials were developed with Merinos d'Arles sheep. In Trial 1, visual observations (VO, i.e., continuous video records) were compared to readings made by 2 rams on 12 ewes. Ewes were allocated into two groups and were followed up for a period of two oestrous cycles i.e., hormonally induced oestrus (Cl) and natural oestrus (C2). In Trial 2, 30 ewes tagged with a caudal transponder were naturally sired by a ram equipped with AD. In Trial 1, despite a widespread of the number of mounts per ewe (i.e., from 2 to 83), the AD allowed detection of 100% of the females that came in oestrus (11/12 in Cl and 8/12 in C2). Hence, when considering only standing oestrus, the coincidence of true mounts reaches 94% (342 readings/364 observed mounts). With regard to males' sexual activity, the first ram M1 did 242 mounts, while only 110 mounts were recorded for the second male M2. Overall Khi-2 analysis confirmed highly significant (p <0.0001) difference in male activity both due to a male difference (M1 > M2) and to a cycle effect (Cl > C2). This decline of sexual activity is assumed to be due to the onset of seasonal anoestrous.In Trial 2, oestrus occurrences, signaled by frequent mountings of the ram, were constantly distributed along time. All ewes displayed an oestrus during the first cycle (C1 i.e., 17 days with the first ram). There is also a wide range in the number of mounts per ewes (from 3 to 205). Remarkably, 2 ewes that were mounted during first cycle came back in oestrus 17 days later as revealed by frequent mountings of the second ram in C2. Lambing dates confirmed the time of conception observed with the AD. As observed in Trial 1, it is however necessary to discard isolated mounts that occurred just after male introduction and did not correspond to standing oestrus (no further readings within 6 h).With the AD device 100% of oestrus ewes were detected. Many researches on reproductive physiology and behavior that can be developed with this device are presented for small-ruminants at large. (C) 2016 Published by Elsevier B.V.

The proportion of anoestrous ewes ovulating after exposure to a sexually active ram is variable mainly due to whether an LH surge is induced. The aim of this study was to determine the role of oestradiol (E 2 ) in the ram-induced LH surge. In one study, we measured the plasma concentrations of E 2 in ewes of different breeds before and after the ‘ram effect’ and related these patterns to the presence and latency of the LH surge, while another compared ovarian responses with the ‘ram effect’ following exposure to rams for 2 or 12 h. In all ewes, the concentration of E 2 increased 2–4 h after rams were introduced and remained elevated for 14.5±0.86 h. The quantity of E 2 secreted before the LH surge varied among breeds as did the mean concentration of E 2 . The granulosa cells of IF ewes collected after 12 h exposure to rams secreted more E2 and progesterone and had higher levels of StAR than the 2 h group but in MV ewes there was no differences between these groups for any of these parameters. These results demonstrate that the LH surge induced by the rams is a result of increased E 2 secretion associated with increased levels of STAR in granulosa cells and that these responses varied among breeds. The results suggest that the variable occurrence of a LH surge and ovulation may be the result of variable ovarian responses to the ‘ram effect’ and insensitivity of the hypothalamus to the E 2 -positive feedback signal. Free French abstract : A French translation of this abstract is freely available at http://www.reproduction-online.org/content/149/5/511/suppl/DC1 .