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The objective of this study was to determine the effect of the weaning method on lamb stress, body weight, sexual behavior, and semen quality of Saint Croix male lambs. The present study was carried out during the late spring and summer of 2018 in the northeast of Mexico. Sixty male lambs born as twins or triplets (3.2 ± 0.6 kg birth weight) and weaned at 60 d of age (19.21 ± 1.8 kg weaning weight) were divided into two weaning methods: complete separation from the dams (CS; the lambs were moved to a pen that was at 500 m of distance from the dams) and separation with contact from the dams (SCD); the lambs were physically separated by a steel mesh that prevented the lambs from having the possibility of sucking milk from their mothers, but they maintained permanent visual and auditory contact. Cortisol levels were determined 3 d before and 7 d after weaning. Lambs were evaluated as 3-month-old lambs for sexual behavior and semen quality for 9 weeks. The effects of the weaning method (M), week (W), and the interaction M × W were significant on body weight and cortisol levels (P<0.001). The SCD lambs had higher cortisol levels at 3, 5, and 7 d after weaning than CS lambs (P<0.001). The CS lambs had higher body weight during the first 4 weeks after weaning than SCD lambs (P<0.001). The weaning method had no effect on scrotal circumference, sexual behavior, and semen quality traits, except for progressive sperm motility, being better for the lambs that were completely separated (P<0.05). The results from this study show that complete separation of lambs and ewes at weaning is an effective method to reduce lamb stress and improve lamb growth after weaning, but it did not have long-term effects on sexual behavior and semen quality of Saint Croix male lambs.

The aim of this study was to determine the semen quality, sexual behaviour and testosterone (T) levels in Saint Croix rams under semi-desert climate conditions. Sixteen rams (70.6 ± 12.5 kg ; 24.1 ± 0.3 months old) were randomly divided into a grazing group (GG, n = 8) and a supplemented group (supplemented individually with 1 kg.d−1 of concentrate (156 g CP.kg−1 DM and 2.5 Mcal EM.kg−1 DM). SG, n = 8). Each group grazed on buffel, grass. Every two weeks, semen was collected, and sexual behaviour traits were evaluated. SG rams had greater body weight (P < 0.0001) and greater semen quality than the GG rams. SG rams had greater values for reaction time and lateral approaches than GG rams (P < 0.0001). No interaction was found between treatment and month for T concentration (P < 0.05) ; the SG rams had greater values during most of the months, but GG rams had greater values during September. Month had a significant effect on T concentration (P < 0.05) with the highest values in autumn. It can be concluded that Saint Croix rams are able to adapt to adverse environmental conditions and that supplementary feed prior to the mating season improves ram sexual behaviour.

El propósito fue evaluar el efecto del remplazo parcial de mazorca de maíz quebrado con maíz molido (MM) o con melaza de caña de azúcar (MCA) en suplementos para vacas de doble propósito. Dieciocho (18) vacas multíparas (414 ± 13 kg de peso vivo, y 106 ± 32 días en lactación) se asignaron al azar a los tratamientos: 1) suplemento testigo (ST) 87% de mazorca de maíz quebrado (MMQ), 11% pasta de soya y 2% urea; 2) reemplazo de 20% de MMQ con 20% maíz molido (MM); 3) reemplazo de 18% de MMQ por melaza (MCA). Cada vaca recibió 5 kg/día en base materia seca (MS) de suplemento, mientras que sus becerros recibieron 1.8 kg/día base MS del suplemento testigo. El experimento duró 11 semanas y los datos se registraron una vez por semana. Se utilizó un modelo mixto de SAS en un diseño completamente aleatorio. Se determinaron márgenes netos de ganancia de leche y carne (kilos de becerro destetado) mediante presupuestos parciales. No hubo diferencias (P>0.05) entre los tratamientos sobre la composición de la leche, la condición corporal ni el aumento de peso diario de las vacas y terneros. Sin embargo, en comparación con el MM, el ST mostró mayor (9.0 %, P0.05) en las demás variables de respuesta. Los márgenes combinados de ganancias netas (ventas de leche y terneros), fueron 9 % mayores para el tratamiento con MCA en comparación con el resto de los suplementos.

This study reports the nutrient composition of leaves of Moringa oleifera harvested at five different dates throughout the year. The leaves of M. oleifera were harvested from Guemez, Tamaulipas, Mexico during the rainy (3 dates) and dry season (2 dates) in 2016–2017. A proximate analysis was carried out on the processed samples using standard analytical procedures. Mineral constituents were wet digested and analyzed using an atomic absorption spectrophotometer and a flame photometer. Harvest date significantly influenced nutrient composition of M. oleifera leaves. The content of neutral detergent fiber increased (during third and fourth harvest dates) as well as acid detergent fiber (during third harvest date) and crude protein declined. The highest crude protein content (26.33%) was observed during the first harvest date. The mineral contents of Ca, Fe, Mg, Mn and Cu varied significantly across harvest dates, except Zn concentration. The ranges of Ca and Mg contents were 1.07–1.78% and 0.18–0.28%, respectively. The ranges of Fe, Zn, Mn and Cu contents were 126–414, 28.2–42.5, 67.9–95.5 and 1.03–5.46 ppm, respectively. The presence of these essential nutrients and minerals suggest that M. oleifera leaves could be utilized as source of feed supplement to improve growth performance and health status of small ruminants in harsh environments with limited feed supply in the dry season.

Agrosilvopastoral systems that integrate crops, pastures, trees and shrubs are seen as a way forward to meet future needs for food, feed, fuel, and other products, as well as for providing environmental and social benefits. Cattle production systems in the tropical and subtropical areas of Mexico have a dual-purpose (milk and beef) objective in agrosilvopastoral systems that need to improve the production of goods, as well as non-productive outputs like environmental services, enhancing their sustainability. The aim of this study was to characterise the socioeconomic, and productive characteristics of dual purpose farms based on agrosilvopastoral systems (ASPS), in a subtropical region in the southern highlands of central Mexico, to contribute in the understanding of how these ASPS operate and their differences. Forty-seven farmers answered a semi-structured questionnaire to identify aspects of farm management, structure, and land use; as well as technical and economic aspects. Information was analysed using factorial analysis of principal components, in order to reduce information, and subsequently cluster analysis that included nine variables resulting into four groups of farms differentiated by structure, size, management and productive orientation. Productive orientation of the farms was from the activity from which farms obtained most of their incomes. The four groups were beef production oriented (BPO) 46.81%, milk production oriented (MPO) 23.40%, pure breed weaned calves (PBWC) 17.02%, and traditional dual-purpose (TDP) 12.77%. Characterization of agrosilvopastoral farms identified main differences and characteristics, as well as the presence and use of trees and shrubs by farmers and cattle.

El objetivo fue comparar los efectos de una metodología para la clasificación de épocas climáticas, que tradicionalmente son utilizadas para establecer épocas de nacimiento (EN) en estudios y experimentos estadísticos. Esta metodología se basa en un índice de aridez (IA) para clasificar las EN utilizando información meteorológica histórica. Se trabajó una base de datos con un pedigrí de 7,460 animales, se ajustaron dos modelos para peso al nacimiento y peso al destete en bovinos Charolais manejados en pastoreo extensivo. Los modelos incluyeron el efecto fijo de grupo contemporáneo (GC= subclase de hato, sexo, año y EN) y edad de la madre. Los mismos modelos se compararon utilizando una clasificación tradicional de estaciones del año para clasificar las EN. Al estimar los componentes de varianza y valores genéticos (DEP) con sus exactitudes, los modelos fueron diferentes de acuerdo a la prueba de razón de verosimilitudes (P

This study aimed to evaluate the effect of reinserting controlled internal drug release (CIDR) devices after fixed-time artificial insemination (FTAI) on pregnancy rates in goats. Oestrus was synchronized with a short (5 days) CIDR protocol, and FTAI was conducted 54 hours after CIDR removal. According to the reinsertion of CIDR after FTAI, goats were assigned to three treatments: G0 control group (n = 29), no CIDR reinsertion ; G7 group (n = 27), CIDR reinserted 7 days ; G14 group (n = 29), CIDR reinserted 14 days. Blood samples were collected to determine progesterone levels. Oestrus appearance (92.9%), interval of CIDR removal to oestrus (IRE = 34.1 ± 1.1 hours), interval of oestrus onset to artificial insemination (IEAI = 20.2 ± 1.0 hours), mean duration of oestrus (38.4 ± 1.4 hours), and pregnancy rates (61.0%) were similar (P > .05) among groups. Progesterone concentrations were higher (P < .05) in G7 and G14 than G0 goats. G7 goats had lower (P < .05) oestrus rate, after CIDR reinsertion, than G0 and G14 goats. Overall pregnancy rate was similar (P > .05) for all groups. In conclusion, reinsertion of CIDR for 7 or 14 days after a short oestrus synchronization protocol and FTAI did not increase the overall pregnancy rate of goats.

Ethnopharmacology relevance Acacia cochliacantha is a small tree whose foliage is traditionally used in Mexico for treatment of kidney pain, gastrointestinal illnesses and to kill intestinal parasites. In recent decades, the study of vegetal extracts has offered other possible alternatives for the control of Haemonchus contortus . Considering that this nematode affects dramatically the health and productivity of small ruminants, the aim of this study was to identify the anthelmintic compounds from A. cochliacantha hydro-alcoholic extract (HA-E) through an ovicidal test. Material and methods In vitro egg hatch assay was conducted to determinate the anthelmintic effects of a HA-E (60 g). Liquid-liquid ethyl acetate/water extraction gave two fractions (EtOAc-F, 1.92 g; Aq-F; 58.1 g). The less polar compounds from ethyl acetate fraction were extracted by addition of dichloromethane offering a precipitate phase (Mt-F, 1.25 g) and a soluble mixture (DCMt-F 1.15 g). All fractions were evaluated for ovicidal activity obtaining the egg hatching inhibition (EHI, 0.07–25 mg/mL). Ivermectin (0.5 mg/mL) was used as a reference drug (positive control), and distilled water, 2.5% DMSO and 2% methanol were used as negative controls. The isolated compounds from the most active fractions were subjected to spectroscopic ( 1 H NMR) Spectrometric (MS) and UV HPLC analysis in order to identify the bioactive compounds. Results The less polar treatments (AcOEt-F, DCMt-F, DCMt-P) showed the highest ovicidal activities (98–100% EHI; at 0.62–1.56 mg/mL) and the major compounds found in these fractions were identified as caffeoyl and coumaroyl derivatives, including caffeic acid ( 1 ), p -coumaric acid ( 2 ), ferulic acid ( 3), methyl caffeate ( 4 ), methyl- p -coumarate ( 5 ), methyl ferulate ( 6 ) and quercetin. In case of the less active fractions (Aq-F, Mt-F) were constituted principally by glycosylated flavonoids. Conclusion These results show that caffeoyl and coumaroyl derivatives from Acacia cochliacantha leaves had promising anthelmintic activity against Haemonchus contortus . This leguminous may offer an alternative source for the control of gastrointestinal nematodes of small ruminants.

Veterinaria Mexico OA ISSN: 2448-6760 Cite this as: Rojo-Rubio R, Gonzalez-Cortazar M, Olmedo-Juarez A, Zamilpa A, Arece-Garcia J, Mendoza-Martinez GD, Lee-Rangel HA, Vazquez-Armijo JF, Mendoza-de Gives P. Caesalpinia coriaria fruits and leaves extracts possess in vitro ovicidal activity against Haemonchus contortus and Haemonchus placei . Veterinaria Mexico OA. 2019;6(4). doi: 10.22201/fmvz.24486760e.2019.4.601. The ovicidal effect of hydro-alcoholic extracts from mature fruits and dried leaves of the Caesalpinia coriariatree , against Haemonchus contortus and H. placei was evaluated by the egg hatching inhibition test (EHIT). Secondary compounds within the extracts were identified by high performance liquid chromatography. Five extract concentrations were assessed in the inhibition tests (25.0, 12.5, 6.2, 3.1 and 1.5 mg/mL), using distilled water and Thiabendazole (0.5 mg/mL) as negative and positive controls, respectively. The results were analysed under a 2 × 2 × 6 completely randomized factorial design, and mean differences were established by the Tukey’s post hoc test. The 50% (EC 50 ) and 90% (EC 90 ) effective concentrations for each extract were determined using a Probit analysis.A concentration-dependent ovicidal effect of hydro-alcoholic extracts from both leaves and fruits was observed, reaching a 100% efficacy against both nematode species with the 25.0 mg/mL concentration (p < 0.05). The EC 50 for the fruit and leaves extracts were established as 1.63 and 3.91 mg/mL, and as 3.98 and 11.68 mg/mL, against H. contortus and H. placei , respectively. The most important secondary compounds identified in extracts were free-condensed tannins, gallic acid and methyl-gallate.In conclusion,hydro-alcoholic extracts from C. coriaria mature fruits and dried leaves inhibit in vitro egg hatching of H. contortus and H. placei .

Mexico has a large beef production industry that has grown significantly in the last decade. The export market has increased, however, domestic beef consumption has declined. A knowledge of the factors affecting consumer perceptions and acceptance of beef might highlight critical points that could improve the whole industry, and lead to an increase of export and domestic consumption. The present paper is aimed to provide an overview on the dynamics of Mexican beef production systems, the current perceptions of the Mexican consumer for beef, and the current available beef quality assurance schemes, based on published and official information.

The objective of this study was to evaluate the effects of three fibrolytic enzyme products (cellulase (CEL), xylanase (XYL) and a 1:1 mixture of CEL and XYL (MIX)) at three dose levels (0, 1 and 3 μL/0.5 g DM) on the in vitro fermentation of a diet for growing lambs. Bottles were incubated for 96 h at 39 °C. A mathematical model was used to estimate the parameters describing the gas production (GP) curve (b, c and L). Dry matter degradability (DMD) and fibre (NDFD and ADFD) degradability were determined at the end of the incubation period. Metabolisable energy (ME) and short chain fatty acids (SCFA) were calculated at 24 h of incubation. The asymptotic GP (parameter b) was affected (p

Cuarenta cabras Alpino Francés (39.3 ± 2.0 kg PVI, primer parto) fueron usadas bajo un diseño completamente al azar para evaluar el efecto de dos fuentes de forraje en la dieta: Alfalfa (Medicago sativa) (T1) y alfalfa + maralfalfa (Pennisetum purpureum Var CT-115) (T2) sobre la respuesta productiva, calidad y perl de ácidos grasos de la leche de cabra en el primer tercio de la lactación (60 d). El consumo de materia seca (CMS) fue similar (p > 0.05) para ambos grupos. Las cabras que recibieron el T1, produjeron 0.52 kg más de leche (p < 0.01), sin efecto signicativo en el contenido de grasa y lactosa;T2 presentó mayor (p < 0.5) consentración de proteínas, sólidos totales, densidad y sólidos no grasos. La concentración de ácidos grasos de cadena corta (AGCC) tendió a ser mayor (p = 0.07) en T1, de manera particular aumentó el caprírico (p < 0.05). Por otra parte, tanto los ácidos grasos de cadena larga (AGCL), como los ácidos grasos mono insaturados fueron mayores (p < 0.05) en T2. El ácido linoleico fue menor (p < 0.01) en T2, lo cual se reejó en una mayor (p < 0.05) concentración de ácido linoleico conjugado (ALC). La inclusión de maralfalfa en la dieta de cabras lecheras Alpino Francés, tiene un efecto positivo en la calidad y perl de ácidos grasos, como el ácido linoleico conjugado, el cual ha demostrado tener efecto benécos en la nutrición y salud humana.

Two studies were conducted to determine reproductive performance (Estrus, EP, and gestation, GP) and ovarian activity (Follicle numbers, FN, and ovulation rate, OR) in goats (M) and does (P). In the first study, 28 P and 44 M females were treated with progesterone vaginal devices (Conipred-CO) and equine chorionic gonadotropin (eCG) doses of 0 (n = 11 P and 10 M), 200 (n = 11 P and 16 M) or 400 (n = 10 P and 14 M) IU. Dose of eCG affected EP in the P (45 to 90%) and the M (63 to 80%) goats, whereas GP was not affected in neither group (64 to 91% for P and 78 to 80% for M) of goats. In the second study, pubertal does were treated with Chronogest sponges and doses of 0, 100, 200 or 400 IU of eCG (n = 5). The eCG dose did not affect FN, values found were 13, 12, 11 and 11 follicles, respectively, for each dose; whereas, OR was greater (P

Thirty-six goats: 15 Alpine (AG), 13 Saanen (SG) and 8 Anglo-Nubian (ANG) were used to evaluate dry matter intake (DMI), body weight (BW) changes and milk production to validate Wood's model in lactation curves. The kids pre-weaning weight, weaning weight (WW) and daily weight gain (DWG) were determined. Milk production was measured daily for a period of 90 d. The DWG was quantified daily, while BW was recorded weekly. Performance of 48 kids (20 AG, 15 SG and 13 ANG), aged 15 d were evaluated. Wood's model was utilised to describe goat's lactation curve in the different studied goat breeds. Milk production was differed between breeds and according to the number of kids suckled (P < 0.05). Both of DMI and BW showed a linear increase (P < 0.05) during the studied period. Both of WW and DWG were unaffected by type of kidding and breed and were higher in males than in females. It is suggested that equation of Wood's model is adequate to describe the lactation curve in studied goat breeds. The ANG and AG breed...

This study was conducted to evaluate the effects of season, year of lambing, parity, and the effect of ram on litter size, birth, and weaning weight through 8 years. Data of 4078 lambs sired by 21 rams and 1072 ewes were analyzed by a lineal model. There was a significant effect (P 0.05) of lambing number on litter size and birth weight, but not on weaning weight (P 0.05). For litter size, the lowest numbers were obtained on the first lambing ewes (1.21 ± 0.03) and the highest ones inewes starting from the fourth lambing (1.69 ± 0.04). Lowest body weights were found in lambs born from first lambing ewes (3.01 ± 0.1 kg) and the highest ones in lambs born from the second (3.14 ± 0.1) to the fifth (3.15 ± 0.2) lambing ewes. The lambing breeding season had a significant effect on weaning weight: the highest weaning weights were recorded in lambs born in spring (12.70 ± 0.20 kg) and the lowest ones in those born in summer (11.93 ± 0.20 kg). Lambing year had a significant effect (P 0.05) on litter size and weaning weight, since the values of both traits improved through the years. Effect of ram was significant (P 0.05) for each of the traits considered: there were differences up to one lamb per litter, also differences up to 1.5 kg for birth weight and up to 6.5 kg for weaning weight among rams. In conclusion, these results indicate that environmental conditions are important source of variation in litter size, birth, and weaning weight in hair sheep under semi-arid climate.

In modern cattle breeding, assisted reproductive technologies in small ruminants have been used even out-of-season breeding, but in emerging countries these technologies have been mainly used for estrous synchronization and artificial insemination. However, in the last 30 years, significant progress in the matter of transfers of in vivo derived and in vitro produced embryos has been achieved. Currently, eight donor embryos are obtained by goat, due to the physiological knowledge of the presence of dominant follicles; above alter results recovered embryos (4 embryos / donor). Whereas, the goat has the advantage of presenting a shorter interval between generations compared to cow; this promote more research in in vitro fertilization, and overcome the limitations presented in a traditional embryo transfer. However cloning and transgenesis, are two techniques that will begin to have a commercial application, because goats can be used as bioreactors to produce milk with specific proteins to develop drugs. The objective of this study was to establish and describe in a general way the use of these techniques in goats, to promote their use so as to achieve genetic improvement in goats. Key words: Reproductive technologies, goats, estrous synchronization, embryo transfer.

The South-Central region of Mexico has experienced a sizeable introduction of purebred horses for recreational aims. A study was designed to assess effective population sizes and genetic diversity and to verify the genetic integrity of four horse breeds. Using a 12-microsatellite panel, Quarter Horse, Azteca, Thoroughbred and Creole (CRL) horses were sampled and analysed for diversity and genetic structure. Genetic diversity parameters showed high numbers of heterozygous horses but small effective population sizes in all breeds. Population structure results suggested some degree of admixture of CRL with the other reference breeds. The highly informative microsatellite panel allowed the verification of diversity in introduced horse populations and the confirmation of small effective population sizes, which suggests a risk for future breed integrity.

Rolando Rojo-Rubio (dr_rojo70@yahoo.com.mx) - Pas de Clé UT Notice à Reprendre -; International audience; Forty-five Pelibuey sheep were experimentally infested with nematodes to evaluate the effect of three free condensed tannin (FCT) levels of Lysiloma acapulcensis on fecal egg counts (FECs), packed cell volumes (PCV), ocular mucosa colors (OMC), average daily gain (ADG), and adult nematode count. Five treatments were used: 12.5, 25.0, and 37.5 mg of FCT kg−1 of body weight (BW); sterile water (control); and ivermectine (0.22 mg kg−1 of BW) as chemical group. The data were processed through repeated measurement analysis. Even though the three FCT doses decreased (P < 0.05) the FEC, the highest reduction was obtained with 37.5 mg kg−1 of BW. No differences were observed in PCV and OMC. Higher ADG (P < 0.05) was observed with 37.5 mg kg−1 of BW of FCT. The count of adult nematodes (females and males) in the higher dose of FCT was similar to chemical treatment. Dose of 37.5 mg kg−1 of BW decreased the parasite infection and improved the lamb performance. Therefore, this dose could be used as a nutraceutic product in sheep production.

The aim of this study was to evaluate the effect of different dose levels of exogenous fibrolytic enzymes (EFE) on in vitro ruminal fermentation kinetics and energy utilization of foliages from three browse trees (Pithecellobium dulce, Heliocarpus velutinus and Guazuma ulmifolia). Mixture of EFE product was added to the leaves of the three browse tree species at three dose levels: 0 (control), 3.5 and 7.0 mg/g of DM. Chemical composition of the foliages, including plant secondary metabolites such as total phenolics (TP), saponins (SAP) and aqueous fraction (AF), was determined. In addition, in vitro assaying of ruminal gas production kinetics was determined for the three browse three foliages treated with EFE. P. dulce had the highest crude protein content (p

An in vitro gas production technique was used to evaluate the effects of copper and zinc supplementation on the amount and rate of gas production, dry matter degradability (IVDMD), utilization of metabolizable energy (ME), and ruminal fermentation patterns using rumen fluid from four Boer male goats as inoculum. The goats were fed twice daily at 07:00 and 19:00 h a total mixed ration containing 10.3 and 22.5 mg/kg DM of Cu and Zn, respectively. This diet was incubated in vitro for 96 h with four treatments being: control, Cu (21.7), Zn (5.6), and Cu-Zn (21.7 and 5.6) which was provided as a mineral premix. Data were analyzed as a completely randomized design. Rates of gas production (RGP) at 4 (RGP(4h)) and 6 h (RGP(6h)) and gas production (GP) at 24 (GP(24h)) and 48 h (GP(48h)) differed (p 0.01) among treatments. An addition of Cu increased the RGP(4h), RGP(6h), GP(24h), and GP(48h) (p 0.0001). The Cu treatment had the highest IVDMD and control the lowest (p 0.05), and the Cu treatment was the highest values of ME and SCFA. The addition of Cu to the in vitro ruminal fermentation increased gas production and efficiency of energy use.

Animal production in tropical regions is commonly limited by the low crude protein content and digestibility of pastures, particularly during the dry season. The objective of the present study was to evaluate the effect of including Enterolobium cyclocarpum leaves (ECL) (0%, 15% and 30%) in diets as a partial replacement for lucerne on dry-matter intake (DMI), weight gain and nitrogen (N) balance in growing Saanen goats (12.6 ± 3.2 kg at 3 months of age) and the digestibility of the diet. Daily weight gain, DMI and digestibility were analysed in a 3 × 3 Latin square design replicated three times. The inclusion of ECL did not affect daily weight gain or DMI (P > 0.05). There were no significant (P > 0.05) differences for N intake among the diets, but the inclusion of 30% ECL significantly (P = 0.01) increased N excreted in faeces. These results suggest that ECL can be used as a partial substitute of lucerne in diets for growing goats, without affecting animal performance.

Quintero-Elisea, J.A., Vazquez-Armijo, J.F., Cienfuegos-Rivas, E.G., Correa-Calderon, A., Avendano-Reyes, L., Macias-Cruz, U., Lucero-Magana, F.A. and Gonzalez-Reyna, A. 2010. Reproductive behavior and efficiency in Pelibuey ewes treated with FGA-PMSG and bred by mounting or laparoscopic intrauterine insemination. J. Appl. Anim. Res., 38: 13–16. To evaluate the effect of 200 IU of PMSG on reproductive behaviour of hair sheep ewes were bred by 1) intrauterine artificial insemination by laparoscopy (IAIL) or 2) natural mount (NM) in Northeast Mexico, and subjected to an estrus synchronization protocol, with fluorogestone acetate sponges for 10 d (40 mg, FGA). Twenty four hours before sponge withdrawal, the ewes were randomly assigned to one of two treatments, T1= 200 IU of PMSG (n= 40) IM or T2= 0 IU of PMSG (n=20). Ewes showing estrus, were divided in two groups, to be served by 1) MN or 2) by IAIL. The PMSG treatment reduced(P

Cattle production is one of the most important livestock activities in the rural areas of Mexico, with most of the national territory dedicated to it, in addition to the use of the most agricultural supplies and forages resources, as well as agricultural and agro-industrial by-products. Mexico is placed among the ten first meat and milk producer countries worldwide, being the Mexican tropical zone one of the main suppliers of such products. One of the main milk sources is the dual purpose cattle, such systems can be described as those that produce milk (daily milking) and meat (calf after weaning), on every productive cycle. They are mainly located in developing regions and characterized by using low-technology and in poor environments, consequently productive levels are considered low. Milk is destined for self-consumption or for sale at local markets and calf after weaning is sold at local feedlots or for export. Regarding to the little information available about the dual purpose systems, the present work is intended to discuss the main characteristics of cattle production in dual purpose systems in Mexico.

The objective of this study was to evaluate sexual behaviour and semen quality of St. Croix ram lambs bred in a semi-desert region. In Experiment 1, 24 yearling rams were assigned to two groups: T1 with 12 males confined for 11 months; T2 with 12 males confined individually for the same period of time. In Experiment 2, 20 four-month-old ram lambs were assigned to two groups of 10 animals each. In each experiment, sexual behaviour and semen quality were evaluated every 2 weeks over 11 months. In Experiment 1, rams that were individually confined showed better sexual activity than lambs confined together (P

The reproduction of small ruminants like goats and sheep managed under extensive range grazing conditions can be affected by nutrients availability and especially by the mineral content of the forages resources on the rangeland. It has been particularly demonstrated that trace elements can have equally, beneficial or detrimental effects, depending on its balance, on reproductive functions in small ruminants. Trace elements as copper, molybdenum, selenium and zinc play key role on the metabolism of carbohydrates, proteins and lipids; however, the mode of action by which these elements affect reproduction in sheep and goats are not completely understood, due to the complexity in the mode of action of the metallobiomolecules and the neuro-hormonal relationship. In this way, their absence or presence of these minerals in several organs, fluids, or tissues of the reproductive tract have allowed obtaining information on the metabolism and the role of these elements on reproduction in sheep and goats. On this regard, the objective of this document is to review the relationships and effects of some trace elements, on reproductive events in sheep and goats.

The reproduction of small ruminants like goats and sheep managed under extensive range grazing conditions can be affected by nutrients availability and especially by the mineral content of the forages resources on the rangeland. It has been particularly demonstrated that trace elements can have equally, beneficial or detrimental effects, depending on its balance, on reproductive functions in small ruminants. Trace elements as copper, molybdenum, selenium and zinc play key role on the metabolism of carbohydrates, proteins and lipids; however, the mode of action by which these elements affect reproduction in sheep and goats are not completely understood, due to the complexity in the mode of action of the metallobiomolecules and the neuro-hormonal relationship. In this way, their absence or presence of these minerals in several organs, fluids, or tissues of the reproductive tract have allowed obtaining information on the metabolism and the role of these elements on reproduction in sheep and goats. On this regard, the objective of this document is to review the relationships and effects of some trace elements, on reproductive events in sheep and goats.

Pelibuey sheep is the main breed in the tropical and subtropical regions of Mexico, and high demand of sheep meat has favored the finishing of lambs in feedlots with diets containing high levels of grains. The objective of this study was to evaluate the effects of exogenous enzymes (EE) and application method on nutrient intake and digestibility and performance of growing Pelibuey lambs. Treatments were based on comparison of two different methods of adding an enzyme product (sprayed on the total mixed ration or applied orally to the lambs) versus control treatment (no added enzyme). Twenty-one Pelibuey lambs, weighing 15.7 kg (SD = 1.8 kg) initial body weight, were individually housed in shaded pens and assigned randomly to one of the three enzyme treatments. At the end of study (lasting for 45 days), three lambs from each treatment were randomly selected and adapted to a pants and harness designed for fecal collection to measure nutrient digestibilities. Total body gain and average daily gain were affected (P

Los factores que afectan las características y composición de la leche de cabra han sido bien estudiados en países de clima templado, pero no en países tropicales como Venezuela. El presente trabajo evaluó el efecto de grupo racial y de algunos factores no genéticos sobre las características fisicoquímicas y composición de la leche de cabras mestizas canarias, para lo cual, se analizaron 758 muestras de leche. Los datos se recolectaron en un periodo de nueve años. Las muestras fueron tomadas de un rebaño caprino multirracial confinado, ubicado en Maracay, en el estado Aragua, Venezuela (10º 16’ 25,30’’ N y 67º 36’ 35’’ O). Los resultados se analizaron mediante un modelo estadístico lineal aditivo, con el padre como efecto aleatorio y como efectos fijos, la edad al parto (EP), año (AP) y mes (MP) de parto, tipo de parto (TP), grupo racial (GR); y las covariables días en producción (efectos lineal y cuadrático). Las medias de las características fueron: crioscopía (ºC): -0,56; acidez (mLNaOH 0,1N/100 mL leche): 19,12; cloruros: (%): 0,22; WMT (mm): 10,75; pH: 6,55; composición de la leche (%): grasa: 4,32; proteína: 4,00; caseína: 2,63; humedad: 86,69; sólidos totales: 13,30; sólidos no grasos: 9,04; cenizas: 0,77 y lactosa: 4,27. Los resultados del estudio, muestran que todos los efectos fijos estudiados, afectaron en forma variable las características y la composición de la leche. El año de parto de la cabra, fue el factor que más influyó sobre la variación de las características de la leche; mientras que el GR ½ Canarias ½ Alpino Francés, estuvo por encima de los demás genotipos en cuanto al contenido porcentual de los diferentes sólidos de la leche. Factors affecting the characteristics and composition of goat milk have been well studied in template countries, but not in tropical countries, such as Venezuela. The purpose of the present investigation was to evaluate the effect of breed group and some non-genetic factors on both characteristics and composition of milk from Canary crossbred goats in tropical conditions. To carry out the study, a total of 758 milk samples were analyzed. Data were collected in a period of nine years and milk samples were taken from a multiracial confined goat herd, located in Maracay, the State of Aragua, Venezuela (10° 16’ 25.30’’ N and 67º 36’ 35’’ W). Data were analyzed by a linear additive statistical model, with sire as random effect; age at calving (EC), year of calving (YC), month of calving (MC), prolificity (P), and breed group (BG), as fixed effects, and the covariates production days, as linear and quadratic effects. The means of the characteristics and composition (%) of goat milk were: cryoscopy (°C): -0.56; acidity (0.1 mL NaOH N/100 mL of milk): 19.12; chlorides (%): 0.22; WMT (mm): 10.75; pH: 6.55. Milk composition (%): fat: 4.32; protein: 4.00; casein: 2.63; humidity: 86.69; total solids: 13.30; non-fat solids: 9.04; ash: 0.77; and lactose: 4.27. The results of this study showed that all the fixed effects studied affected in a variable form, the characteristics and components of milk, being YC the most influential factor on the variation of the characteristic of milk. The BG “½ Canarian ½ Alpine” highlighted above all other genotypes, regarding the percentage content of the different solids of milk.

El objetivo del presente trabajo fue evaluar la inclusión de la cáscara de naranja deshidratada (CND) en dietas integrales, sobre la producción y la composición de la leche de cabras. Se utilizaron 24 cabras multíparas Boer x Saanen, con peso medio de 39,2 ± 2,3 kg. Los tratamientos consistieron en cuatro dietas integrales con diferentes niveles de inclusión de CND (0, 10, 20 y 30%). A partir del último tercio de gestación se asignaron al azar los tratamientos, los cuales fueron proporcionados hasta el final de la lactancia, ocho semanas posteriores al parto. Las variables analizadas fueron la producción de leche y los porcentajes de proteína, grasa, lactosa y sólidos no grasos. La producción de leche promedio obtenida en el presente trabajo fue de 0,884 ± 0,026 L, la cual no se afectó por los tratamientos. Los tratamientos afectaron el porcentaje de grasa en leche (P