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Simple Summary: In the Americas, the Comarca Lagunera (CL), located in North-arid Mexico, concentrates one of the main dairy cattle hubs (>500,000 Holstein cows) managed under highly technified-industrial schemes. Dairy cows' nutrition is based on the use of total mixed rations; whereas feed rejection (i.e., 3–5%) has been observed, such feed-leftovers retain a high-pitched nutritional value. The CL also holds an emergent sheep industry, which exhibited the largest production value growth (i.e., >580%; 2010–2023). With that in mind and considering a circular economy perspective, we envisioned a research opportunity. Our working hypothesis states that a basal diet founded on such dairy cow feed-leftovers and aligned with short-term supplementation (i.e., 40 d) with Withania somnifera L. (Ashwagandha) will enhance some reproductive and behavioral outcomes in Black Belly rams. Such approach should bridge these two interesting animal production systems in the CL. Considering a circular economy perspective, this study evaluates the possible effect of targeted short-term supplementation with Withania somnifera L. (WS; Ashwagandha) on ram's seminal quality, socio-sexual behaviors, and blood constituents. Black Belly rams (n = 20) received a basal diet comprising feed-leftovers from dairy cows in the north-arid Mexico (i.e., Comarca Lagunera CL). The experimental units, with proven libido and fertility, were homogeneous in terms of age (3.41 ± 0.21 yr.), live weight (LW; 53.8 ± 3.3 kg), body condition (BC; 2.96 ± 0.01 units), initial sperm concentration (2387 ± 804 × 106), and viability (23.9 ± 15.6%). Rams were randomly assigned during the transition reproductive period (i.e., May to Jun; 25° NL) to three treatment groups: non-supplemented control group (CONT; n = 6), low WS-supplemented (LWS; i.e., 100 mg kg LW−1 d−1 × 40 d; n = 7), and high-WS-supplemented (HWS; i.e., 200 mg kg LW−1 d−1 × 40 d; n = 7). The basal leftover diet was offered twice daily (0700 and 1600 h); the experimental period (EP) lasted 47 d. No differences (p > 0.05) among treatments occurred regarding LW and BCS at the onset of the EP. Whereas the greater scrotal circumference (SCRC, cm) arose in the LWS and CONT rams, an increased ejaculated volume (VOLEJA, mL) occurred in the WS-rams. A total of 5/9 (i.e., 55%) appetitive and 3/3 (i.e., 100%) consummatory sexual behaviors favored (p < 0.05) the WS-rams, particularly the HWS rams, towards the final EP. The same was true (p < 0.05) regarding the hemogram variables white blood cell count (×109 cells L−1), hemoglobin concentration (g dL−1), and medium corpuscular volume (fL). This study, based on a rethink–reuse–reduce enquiry approach, enabled connectedness between two noteworthy animal systems in the CL: dairy cows and meat sheep schemes. Certainly, the use of dairy cow feed-leftovers aligned with the short-term supplementation with WS promoted enhanced testicular function, augmented seminal volume, and an increased sexual behavior in Black Belly rams in northern Mexico. Finally, while our research outcomes should enhance not only the resilience and sustainability of sheep production and the well-being of sheep-producers and their families, it may also embrace clinical translational applications. [ABSTRACT FROM AUTHOR]

Founded on a circular economy perspective, the possible effect of targeted supplementation with leftover feed from dairy cows (i.e., intensive system) upon the productive economic performance of crossbred–rangeland goats (i.e., extensive system) in northern arid Mexico was assessed. Multiparous goats (n = 38) with similar body condition score (BCS) and body weight (BW) were randomly assigned during the deep anestrus season (i.e., March–April, 25° N) into two groups: (1) the control-non-supplemented group (CONT; n = 19; BCS: 1.76 ± 0.06; BW: 44.3 ± 2.5 kg) and (2) the supplemented group (SUPL; n = 19; BCS: 1.76 ± 0.07; BW: 43.7 ± 1.8 kg). While the SUPL group received 400 g goat d−1 of dairy cow feed leftovers prior to grazing, both groups went daily to the rangeland (i.e., ≈8 h). The study considered an experimental period of 36 d with an experimental breeding of 11 d (d0–d10). Previously, on days −20, −10, −1 preceding the male-to-female interaction, the anovulatory status of goats was confirmed through ultrasonographic scanning. Prior to mating, the males were separated from goats and treated for a period of 3 weeks (i.e., every 3rd d) with testosterone (i.e., 50 mg i.m.). The response variables evaluated considered goats induced to estrus (GIE, %), goats ovulating (GO, %), ovulation rate (OR, units), pregnancy rate-1 (PRd36, %), pregnancy rate-2 (PRd50, %), embryo mortality-d50 (EMO, %), potential kidding index-d50 (PKId50,%), kid weight at birth simples (KWBS, kg), potential litter efficiency at birth (PLEB, kg), and potential litter efficiency at weaning (i.e., d21 post kidding), either expressed as kg head−1 (PLEW1) or USD head−1 (PLEW2). Although no differences (p > 0.05) occurred for GIE and PRd50, increases in the phenotypic expression of OR (1.42 vs. 0.73), PRd36 (68.4 vs. 36.8), EMO (23.0 vs. 0), PKId50 (74.7 vs. 26.8), and KWBS (4.1 vs. 3.3) occurred (p < 0.05) in the SUPL goats. To have a more integrative evaluation regarding the out-of-season reproductive outcomes, three bio-economic efficiency indices per goat exposed to males were generated: PLEB (4.3 vs. 0.6 kg), PLEW1-kg (7.7 vs. 3.1 kg), and PLEW2-USD (63.9 vs. 26.1 USD), which also favored (p < 0.05) to the SUPL goats. The last result occurred despite no differences (p > 0.05) regarding BW, BCS, and serum glucose concentrations between experimental groups. Furthermore, applying the main research outcomes from this specific study toward the large-scale goat production system in the Comarca Lagunera—one of the largest dairy goat production hubs in The Americas—denoted promising expectations, either from an economic or productive–reproductive standpoint. Certainly, goat producers from the region would increase their potential annual income just from the sale of kids by close to 250%; that is from MUSD 1.1 to 3.9. This result should reduce food insecurity and economic stress, as well as enhance the livelihoods of the goat keepers and their families. [ABSTRACT FROM AUTHOR]

The possible effect of body condition score (BCS) on ovarian function, sexual behavior, (i.e., females and males; appetitive and consummative), estrus, ovulation, and reproductive performance was investigated in crossbred dairy goats under extensive conditions. Based on their BCS, female goats (n = 48) were divided into two experimental groups, either with a low (LG; 1.0 ± 0.2 units; n = 26) or with a high BCS (HG: 2.5 ± 0.9 units; n = 22). Bucks n = 4; cc = 2.5. Female sexual behavior (i.e., acceptance of anogenital sniffing and approach, flight, and tail wagging) was higher in the HG (p < 0.05). In addition, bucks exposed to HG goats showed more approach and mounting attempts (p < 0.01). There were no significant differences (p > 0.05) between the groups in either the follicular diameter or size. Interestingly, although follicular volume, pregnancy rate, kidding rate, and total number of kids born alive were higher in the HG goats (p < 0.05), there were no significant differences (p < 0.05) in fetal mortality and prolificacy between the HG and LG goats. In addition, the response variables of female ovulation, total number of corpus luteum, ovulation rate, corpus luteum diameter, and luteal tissue volume were more favorable in the HG goats (p < 0.05). Our research results demonstrate that a higher BCS improves not only the reproductive responses, but also sexual behavior (i.e., female and male). Larger ovarian structures, higher ovulation rates, higher pregnancy and kidding rates, and higher prolificacy were observed in the HG goats managed under a marginal semiarid extensive production system. [ABSTRACT FROM AUTHOR]

Social hierarchies among animal species are established on the dominance-aggressiveness level of the animal aligned with the subordination of their mates. This study aimed to evaluate the association among social rank hierarchy, scrotal circumference (SC), semen quality (SQ), and sexual drive (SD). Adult Dorper rams (n=24) with similar live weight (LW), body condition score (BCS), and age (AG) were subjected to a behavioral test to define the success index (SI) based on male-to-male interactions, determining three social ranks: low hierarchy rams (LHR; SI = 0-0.33; n=9), medium hierarchy rams (MHR; SI=0.34-0.66; n=10) and high hierarchy rams (HHR; SI= 0.67-1; n=5). Afterward, the SC, SQ, and SD were evaluated. The GLM procedure of SAS (SAS Institute, Cary, NC) was used to analyze LW, AG, BCS, SC and SQ variables such as ejaculate volume, and sperm concentration. Microscopic characteristics of sperm cells were subjected to an ANOVA using the MIXED procedure of SAS. The GENMOD procedure was used to assess the effect of social rank (three levels) on the SD variables. Differences were considered as significant at P < 0.05. SC was greatest (P< 0.05) for HHR rams (40.0±3.5) and least for rams with medium social rank (MHR; 29.3±1.20). SQ was greatest (P< 0.05) for HHR rams (3,848±187) and least for LHR (2,660±463). The rejection percentage to mount an estrous ewe or SD was 77.7 for LHR and 20% for HHR and MHR rams (P < 0.05). To conclude, the HHR rams presented the highest successful copulation, the greatest scrotal circumference, and the greatest sperm cell concentration compared with rams with lesser social rank scores. [ABSTRACT FROM AUTHOR]

Usually, social order is defined by the animal size, live weight, or age. This study aimed to evaluate the association among horn presence (HP), and horn size (HS) on social rank hierarchy. Adult Dorper rams (n=24) with similar live weight (LW), body condition score (BCS), and age (AG) were subjected to a behavioral test to define the success index (SI, ranked form 0 to 1) based on male-to-male interactions, determining three social ranks: low hierarchy rams (LHR; SI = 0-0.33; n=9), medium hierarchy rams (MHR; SI=0.34-0.66; n=10) and high hierarchy rams (HHR; SI= 0.67-1; n=5). Afterward, skull, horn (HP and HS), and body morphometrics were measured. The GLM procedure of SAS (SAS Institute, Cary, NC) was used to analyze LW, AG, BCS, HS and HP with three social ranks and five to ten replicates per group. Rams within social rank were the experimental units. Differences were considered as significant at P < 0.05. Regarding HP, 80% of the HHR rams had horns, while 77.7% of the LHR rams were hornless, with intermediate values for MHR (50%), but no differences were found regarding HS between low, medium and high hierarchy rams (85.1±2.6, 84.3±3.3, and 90.7±4.7, respectively). In conclusion, while presence of horns have an important role for establishing social hierarchy, it is a complex trait influenced by factors other than horn presence or size so, we recommend more research in relation to other factors that could influence the position of rams in the hierarchy rank levels of the herds. [ABSTRACT FROM AUTHOR]

Limited data is available on reproductive seasonality in French Alpine goat bucks raised under intensive conditions in northern Mexico, at subtropical latitude (26° N). A study was done of eleven young French Alpine bucks subject to natural, regional photoperiod variations (13:41 h/light at summer solstice; 10:19 h/light at winter solstice). Animals were fed alfalfa hay (17% CP) ad libitum and a commercial supplement (14% CP) at 200 g animal-1 day-1 during the experimental period (December to September). Sperm motility increased (P<0.05) from 1.5 units from January to May to 2.5 units from July to September. Sperm viability also increased, from 25 % in January to May to 40 % in July to September. Ejaculate volume was 0.1 ± 0.03 ml ejaculate-1 from January to July, lower (P<0.05) than the 0.5 ± 0.04 ml ejaculate-1 recorded in August, September and December. Latency to ejaculate in an artificial vagina decreased (P<0.05) from 102 ± 7 sec in December to July, to 52 ± 1 sec in August and September. The studied French Alpine bucks exhibited seasonality in semen quality characteristics, body and testicular variables and sexual response, with generally lower variable values and less sexual activity from January to July followed by increased values and activity. [ABSTRACT FROM AUTHOR]

The high temperatures recorded during the summer season in hot regions compromise the reproductive capacity of domestic animals. In rams, heat stress (HS) causes in the body a series of physiological, metabolic, endocrine and molecular adjustments in order to maintain normothermia and survive; however, several of these changes are negatively associated with their fertility, mainly endocrine ones. HS in rams causes a decrease in blood testosterone concentrations through different mechanisms, and this is negatively reflected on the process of spermatogenesis and sexual behavior. Consequently, heat-stressed rams exhibit low seminal quality and libido; at the sperm level, structural and DNA damage has been observed. Given this situation, the use of HS mitigation strategies during the summer in sheep farms in hot regions is recommended, such as the use of shades in pens, administration of antioxidants or modifications in the diet. Therefore, the objective of this document is to review the current knowledge regarding the effect of HS on the thermoregulation and reproductive capacity of rams, as well as the application of strategies for its mitigation. [ABSTRACT FROM AUTHOR]