Comparison of different diluents based on liposomes and egg yolk for ram semen cooling and cryopreservation.

BACKGROUND: Sperm cryopreservation is an important tool for breed improvement, nonetheless, spermatozoids of rams are extremely sensitive to cryopreservation. AIMS: The present research was to compare a liposome-based (OptiXcell: OX) diluent, a commercial TRIS-egg yolk (Optidyl: OP) and a citrate egg yolk-based (CY) diluent on ovine semen quality through the cryopreservation process. METHODS: Semen was collected from four sexually mature Dorper rams during the natural breeding season. After collection, semen was evaluated and diluted in OX, OP or CY diluent and was cooled from 37°C to 4°C for 2 h (refrigerated semen, RS), after that semen-filled straws were placed in liquid nitrogen (LN) vapour for 10 min, then immersed into LN at -196°C (cryopreserved semen, CS) and stored until evaluation. RESULTS: For fresh semen (FS), similar values (P>0.05) were obtained from the 3 diluents [motility (4.2 ± 0.3), viability (75.4 ± 3.2), hypo-osmotic swelling test (HOST) (59.2 ± 2.1), and normality (84.7 ± 3.5)]. The motility values were higher for RS with OX and CY (4.0 ± 0.2 and 3.6 ± 0.3, respectively) compared to OP (3.0 ± 0.21; P<0.05). The viability was reduced after refrigeration and freezing (P<0.05). Refrigerated semen viability was similar for OX (65%), CY (63%) and OP diluents (60%; P>0.05), but for frozen semen, viability was lower in the CY diluent (P<0.05). Membrane integrity (HOST) in OX (53.6 ± 1.7) was similar to that in OP (50.7 ± 1.5; P>0.05) but higher than in CY (48.7 ± 1.5; P<0.05). CONCLUSION: No difference was found between the OX diluents and those made with egg yolk in terms of sperm parameters; however, the OX diluent was more efficient in protecting the integrity of membrane in freezing/thawing semen.

Economic evaluation of the environmental impact of a dairy cattle intensive production cluster under arid lands conditions.

At a global level, dairy cow production systems (DCPS) are important sources of nourishment and profits, but they generate environmental impacts such as overexploitation of different resources including water, lands and fossil energy. Quantification of water and carbon footprint to define mitigation strategies and a more rational use of natural resources, is a reiterated claim. The aim of this study was to perform an economic evaluation of the environmental impact of the DCPS from the Comarca Lagunera, Mexico (24°N, 102°W, 220 mm, hot-semiarid climate) We contrasted the economic value (EV) generated by the DCPS with respect to the economic costs (EC) due to the greenhouse gas emissions (GHGE) and the water footprint (WFP) of this DCPS. While quantifications of GHGE considered those proposed by the Intergovernmental Panel on Climate Change, the WFP involved the use of blue, gray and green water by the DCPS and related activities. Quantification of the EC of WFP considered an international average price of water. In the year 2017, the Comarca Lagunera registered a dairy cow inventory of 493 144 heads, with 227 142 lactating cows, which produced 2386 million liters of milk per year with an annual average EV of €525.3 million. The EC (€, millions) generated by the GHGE and WFP were €311.8 and €11 980.7, respectively, with a total EC of € 12 292.5 million. When the EV of milk production and the total environmental EC are compared, the contrast demonstrates not only the noteworthy environmental impact but also the significant and senseless biological and EC. In addition, having a large dairy cow concentration creates pollution concerns and the DCPS transfers both nutrients and water resources from an ecologically vulnerable arid region. Therefore, some mitigation strategies such as, better cow genotype, feed and manure management combined with the production of forages and grains in a different geographical region are suggested to promote an optimum use of water in order to uphold the social, economic and biologic sustainability of the Comarca Lagunera, Mexico.

Exposure of sexually inactive males to estrogenized females increased the investigative and consummatory sexual behavior.

Two trials were conducted to evaluate the effect of diverse socio-sexual cues upon male sexual behavior and the reproductive performance of anestrous does (AD). Trials were conducted in northern Mexico (26°N) during the natural anestrous season (Feb-Mar) with crossbred dairy bucks. In Experiment 1, sexually inactive bucks (SIB, n=12) were randomly allotted to three groups, four males/group: a) DEE 9novelty stimulation) - daily exchange of estrogenized females (EF) 12&12h, b) NEE (no novelty stimulation) - no-exchange of EF, 24h, or c) CON (saline-treated_ -daily exchange of AF 12&12h. Sexually active bucks (SAB) from the DEE, NEE and CON groups were subsequently exposed to AD (n=72; n=24/group) and the reproductive outcomes were recorded. In Experiment 2, SAB (n=12; n=6/group) were randomly divided in: 1) B+EF - males+four-EF exposed to AF (n=36), and 2) B+NEF; males+four-saline-treated AD and exposed to AD (n=36). Prior to the onset of the experimental breeding in both experiments, the investigative (ISB), consummatory (CSB) and resting (RSB) sexual behavior of males were quantified (2h×d×2d). Sexual behaviors considered were: ISB - flehmen, ano-genital sniffing, approaches, vocalizations, kicking, penis extrusion, CSB; mount attempts and mounts, and RSB - isolation, attempted escape, aggression and distractions. While EF were an effective stimulus (P<0.05) for evoking mounting in SIB males, daily exchange of estrous does used to stimulate males promoted an enhanced response (P<0.05) in terms of both ISB and CSB. After being exposed to AD, the B+EF bucks induced an earlier estrous response (P<0.05) as compared with the B+NEF bucks. The untreated females did not induce any sexual activity in males and stimulation of ovarian function did not occur when saline treated (CON) AD were exposed to AD. Also, the B+EF group induced an enhanced increase (P<0.05) of the male ISB and CSB, inducing in turn an increase percentage onset of estrus in does that had previously been anestrus (P<0.05).

Reproductive outcomes of Alpine goats primed with progesterone and treated with human chorionic gonadotropin during the anestrus-to-estrus transition season.

This study aimed to determine the possible effects of a single injection of human chorionic gonadotropin (hCG) as a means for estrus induction in acyclic French-Alpine goats during the reproductive transition period at 25°N, 103°W. The potential effects of hCG upon ovarian function and reproductive performance of goats were also assessed. Multiparous acyclic French-Alpine goats (n = 39; 37.4 ± 8 .5 kg) were primed with 20mg progesterone (P4) 1 day prior to hCG administration. Thereafter, does were treated either with saline (hCG-0; n = 10), 50 (hCG-50; n = 9), 100 (hCG-100; n = 10), or 300 IU of hCG (hCG-300; n = 10). Ovarian structures and pregnancy were monitored by transrectal ultrasonography. In addition, after hCG application, goats were monitored twice daily (0800 and 1800 h) to detect estrus signs, with the use of aproned, sexually active bucks treated with testosterone. Goats were bred 12h after the onset of estrus. Two days after hCG administration, the number of large follicles was higher (P < 0.05) in the hCG-50 and hCG-300 groups (1.7 ± 0.1 and 1.8 ± 0.2, respectively) compared with the hCG-100 and hCG-0 groups (1.4 ± 0.2 and 1.1 ± 0.1, respectively). Although none of the hCG-0-goats depicted estrus, the estrus response from the hCG-50, hCG-100, and hCG-300 groups over the 7-d breeding period was 67%, 100%, and 90%, respectively (P > 0.05), being always accompanied by ovulation. Pregnancy rate (67, 100, and 70%), kidding rate (55%, 80%, and 70%), and litter size (1.6 ± 0.5, 1.5 ± 0.5, and 1.5 ± 0.5) for hCG-50, hCG-100, and hCG-300, respectively, did not differ among the hCG-treated does. Therefore, the combined use of P4-priming plus a 100-IU hCG injection is an effective protocol for inducing estrus in non-cycling Alpine goats during the anestrus-to-estrus transition period, which is of key importance for both goat producers and industrializers.

Effects of supplementation during late gestation on goat performance and behavior under rangeland conditions.

This study evaluated the effects of peripartum feed supplementation on doe and kid BW and BCS, milk yield and composition, serum metabolites, and maternal-neonatal behavior under rangeland conditions in northern Mexico. Adult does ( = 23) were randomly assigned to 3 nutritional plane groups: 1) goats supplemented (500 g of concentrate [18% CP/kg DM, 2.7 Mcal/kg DM, and 2% salt]) from 15 d prepartum to 7 d postpartum (G15; = 8), 2) the same supplementation as G15 but from 35 d before until 7 d after kidding (G35; = 8), and 3) nonsupplemented does (GC; = 7). Supplemented goats differed from GC goats in BW (48 ± 1.8, 46.1 ± 2.5, and 44.9 ± 2.3 kg; < 0.05), milk yield (1.8 ± 0.1, 1.9 ± 0.2, and 1.2 ± 0.1 kg at d 15 postpartum; < 0.01), kid birth weights (3.8 ± 0.2, 3.6 ± 0.2, and 3.4 ± 0.2 kg; < 0.05), and kid BW at 15 d after birth (6.9 ± 0.2, 6.6 ± 0.2, and 5.6 ± 0.2 kg; < 0.05) for the G35, G15, and GC, respectively. Serum concentrations for total protein, glucose, and cholesterol were not affected ( > 0.05) by treatments. Milk of GC goats showed increased ( < 0.05) percentages for fat, protein, lactose, and nonfat milk solids, whereas total quantities of these variables where higher ( < 0.05) in the G15 and G35 groups. Furthermore, GC dams spent more time seeking their offspring and emitted more low-pitched bleats 4 h postpartum ( < 0.05) in a 2-choice test compared with the G15 and G35 groups. In general, peripartum supplementation promoted a closer dam-kid relationship at 8 h postpartum. Goat performance may be improved in this semiarid region of Mexico with marginal production through supplementation in late gestation.

Glutamate supply positively affects serum cholesterol concentrations without increases in total protein and urea around the onset of puberty in goats.

Different neurotransmitter and neuromodulatory systems regulate synthesis and secretion of GnRH. Whereas the endocrine and neural systems are activated in response to the metabolic status and the circulating levels of specific blood metabolites, glutamate receptors have been reported at hepatic level. This study evaluated the possible effect of glutamate supplementation upon changes in serum concentrations across time for total protein (TP), urea (UR) and cholesterol (CL) around the onset of puberty in goats. Prepuberal female goats (n=18) were randomly assigned to: (1) excitatory amino acids group, GLUT, n=10; 16.52±1.04kg live weight (LW), 3.4±0.12 body condition score (BCS) receiving an i.v. infusion of 7mgkg(-1) LW of l-glutamate, and (2) Control group, CONT, n=8; 16.1±1.04kg LW, 3.1±0.12 BCS. General averages for LW (23.2±0.72kg), BCS (3.37±0.10 units), serum TP (65.28±2.46mgdL(-1)), UR (23.42±0.95mgdL(-1)), CL (77.89±1.10mgdL(-1)) as well as the serum levels for TP and UR across time did not differ (P>0.05) between treatments. However, while GLUT positively affected (P<0.05) both the onset (207±9 vs. 225±12 d) and the percentage (70 vs. 25%) of females showing puberty, a treatment×time interaction effect (P<0.05) was observed in the GLUT group, with increases in serum cholesterol, coincident with the onset of puberty. Therefore, in peripuberal glutamate supplemented goats, serum cholesterol profile could act as a metabolic modulator for the establishment of puberty, denoting also a potential role of glutamate as modulator of lipid metabolism.

Short-term beta-carotene-supplementation positively affects ovarian activity and serum insulin concentrations in a goat model.

In early October 2010, adult goats (no.=22, 3.5 yr old, 7/8 Sannen-Alpine, 26° N, 103° W, at 1117 m), were randomly assigned to: i) beta-carotene group (BC) [no.=10; live weight (LW)=45.9±1.97 kg, body condition score (BCS) =3.04±0.08; orally supplemented with 50 mg of BC per goat per day]; ii) control group (CONT) (no.=12; LW=46.2±2.04 kg, BCS=3.0±0.08). Animals received a basal diet of alfalfa hay, corn silage, and corn grain, having free access to water, shade, and mineral salts. During the second half of October, estrus was synchronized by using intravaginal sponges. Thereafter, by mid-follicular phase, an intensive blood sampling (6 h × 60 min) was performed to evaluate serum insulin concentrations (INS) by radioimmunoassay. By the end of the luteal phase, an ultrasonographic scanning was performed to evaluate total ovarian activity (TOA) [TOA=total follicles (TF) + total corpus luteum (TCL)]. The whole experimental period consisted of 34 days pre- and 17 days post-ovulation, for a total of 52 days. Average LW and BCS did not differ (p>0.05) during the experimental period. Nonetheless, increases in TF no. (5.0 vs 3.4±0.6 units; p=0.05), TCL no. (3.4 vs 2.8±0.2 units; p=0.05), TOA (8.1 vs 6.2±0.6 units; p=0.05) and INS (4.6 vs 3.9±0.4 ng ml-1; p=0.05) favored to the BC-supplemented group. A positive correlation between LW (r(2)=0.42; p=0.04) and BCS (r(2)=0.47; p=0.02) with respect to ovulation rate, was detected. BC-supplementation increased ovarian activity in the female goat while positively affected the release pattern of insulin, suggesting a potential role of BC as a central and/or pancreas-activating molecule in adult goats; such results may hold not only physiologic but also clinical significance.