Goat production concentrated in developing countries (tropics, dry areas), contributes largely to the livelihoods of low and medium income farmers. Farming systems in these areas have evolved to cope with the formidable constraints imposed by harsh natural and economic conditions by adapting integrated crop/livestock production strategies. In Asia, Africa and Latin America, due to its almost exclusive extensive nature, goat production relies mainly on grazing on communal lands that hardly provide the minimum nutrient requirements due to overstocking and degradation. While some of these production systems are becoming semi-intensive, appropriate breeding strategies should be designed to promote conservation and improvement of their unique attributes, such as adaptability, water use efficiency and suitability under harsh climatic conditions. In Europe, dairy goat production is more common around the Mediterranean basin, where it is important from an economic, environmental and sociological perspective to the Mediterranean countries: Spain, France, Italy and Greece. Europe owns only 5.1 % of the world's dairy goat herds, but produces 15.6 % of the world's goat milk; this is the only continent where goat milk has such an economic importance and organization. In developing countries the dairy goat sector requires a systemic approach, whereby nutrition, animal health, breeding, know-how, inputs and technologies must be assembled. This would allow the optimization of natural and local resources and would promote the transition from a risk reduction strategy towards an increased productivity strategy. Such an increase would privilege production efficiency based on clean, green and ethical practices for responsible innovation.

Records representing data from 1,500 barren Holstein cows over an 8-yr period from a large commercial dairy farm in northern Mexico were analyzed to determine the effects of lactation number and season and year of initiation of lactation on milk production of cows induced hormonally into lactation and treated with recombinant bovine somatotropin (rbST) throughout lactation. Peak and 305-d milk yields were also assessed as predictors of total milk yield in cows induced into lactation. A significant quadratic relationship was found between 305-d milk yield and number of lactation [7,607±145 and 9,548±181 kg for first- and ≥6-lactation cows, respectively; mean ± standard error of the mean (SEM)] with the highest production occurring in the fifth lactation. Total milk yields of cows with ≤2 lactations were approximately 4,500 kg less than milk yields of adult cows (the overall average ± standard milk yield was 13,544±5,491 kg per lactation and the average lactation length was 454±154 d). Moreover, 305-d milk production was depressed in cows induced into lactation in spring (8,804±153 kg; mean ± SEM) and summer (8,724±163 kg) than in fall (9,079±151 kg) and winter (9,085±143 kg). Partial regression coefficients for 305-d milk yield and peak milk yield indicated an increment of 157 kg of milk per lactation per 1-kg increase in peak milk yield (r(2)=0.69). Neither peak milk yield (r(2)=0.18) nor 305-d milk yield (r(2)=0.29) was accurate for predicting total milk yield per lactation. Year, parity, and season effects had significant influence on milk yield of cows induced into lactation and treated with rbST throughout lactation, and peak milk yield can assist in the prediction of 305-d milk yield but not total milk yield. This study also showed that hormonal induction of lactation in barren high-yielding cows is a reliable, practical, and affordable technique in countries where rbST treatment and prolonged steroid administration of dairy cows are legally permitted.

Twenty Dorper × Pelibuey primiparous ewes were used to evaluate effects of seasonal ambient heat stress (i.e., spring vs. summer) on physiological and metabolic responses under production conditions in an arid region. Ten ewes experiencing summer heat stress (i.e., temperature = 34.8 ± 4.6 °C; THI = 81.6 ± 3.2 units) and 10 under spring thermoneutral conditions (temperature = 24.2 ± 5.4 °C; THI = 68.0 ± 4.8 units) were corralled together to measure rectal temperature, respiratory frequency, and skin temperatures at 0600, 1200, 1800, and 2400 h on four occasions over 40 days. Blood metabolite and electrolyte concentrations were also measured at 0600 and 1800 hours. Data were analyzed with a completely randomized design using repeated measurements in time. Rectal and skin temperatures, as well as respiratory frequency, were higher (P < 0.01) in summer than spring at all measured days. Blood serum glucose, cholesterol, triglycerides, and chlorine concentrations were lower (P < 0.01) in summer than spring at 0800 and 1800 hours. In contrast, summer heat stress increased (P < 0.01) blood urea and potassium concentrations at 0800 and 1800 hours. Compared with spring thermoneutral conditions, summer heat stress affected the physiological and metabolic status of hair breed ewes in an arid region, which included blood metabolite and electrolyte adjustments to efficiently cope with summer heat stress.

The aim of this study was to evaluate effects of free ferulic acid (FA) supplementation on productive performance, some blood metabolite concentrations, and carcass characteristics of ewe lambs finished in a feedlot. Dorper×Pelibuey ewe lambs (n=20; BW=28.5±0.5 kg; age=5 mo) were individually housed in pens and assigned under a randomized complete block design to the following dietary treatments (n=10): daily feeding without (control) or with 300 mg of FA/animal. The feedlot feeding period lasted 34 d and then all ewe lambs were slaughtered. Free FA did not affect (P≥0.16) BW gain, ADG, DMI, and G:F during the first 17 d, but BW gain (P=0.10) and ADG (P=0.10) tended to decrease for FA from d 17 to 34 and from d 1 to 34 without affecting (P≥0.16) DMI and G:F in ewe lambs. Serum concentrations of glucose, cholesterol, triglyceride, total protein, and urea were not affected (P>0.05) by FA at d 1, 17, and 34 of the feeding period. Carcass characteristics were not affected (P>0.05) by FA. Stomach percentage tended (P=0.08) to decrease and leg yields increased (P=0.02) for FA. Other noncarcass components and wholesale cut yields were not affected (P>0.10) by FA. In conclusion, FA supplementation did not improve productive performance, metabolic status, and carcass characteristics of ewe lambs receiving a feedlot finishing diet.

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Establishment of the hypothalamic-hypophyseal-gonadal function is dependent on the highly controlled and dynamic interactions between regulatory signals from the brain, pituitary and gonads, all of them leading to the attainment of reproductive capacity, where a coordinated and timely activation of GnRH neurons must occur. The GnRH neurons extend their neurosecretory axons to the hypothalamus where GnRH is released into the pituitary portal vessels to elicit the secretion of LH and FSH, which in turn, will promote gonadal development and support reproductive physiology. Genetic studies have demonstrated that disabling mutations and targeted deletions of the G-protein-coupled receptor (GPR54) generated hypogonadotropic hypogonadism. This link between GPR54 and reproduction, generated attention to the natural ligands of the GPR54 receptor, known as kisspeptins, which are translational products of the hypothalamic gene KiSS1. Recent advances in kisspeptin research have defined a major role of this molecule in controlling the onset of the reproductive function observed at puberty. The aim of this review is to highlight the basic endocrine and genetic concepts involved in the establishment of the hypothalamic-hypophyseal-gonadal axis function which promotes the onset of the reproductive function during puberty. The review highlights what is currently known about the kisspeptin-GPR54 signalling system in the activation of the GnRH neurons.

The effect of beta-carotene supplementation upon luteal activity, measured as number (CLT) and volume (VLT) of corpus luteum, and P4 synthesis in goats, was evaluated. Goats (n = 22, 34 months) were randomly assigned to one of two experimental groups: (i) beta-carotene [Beta, n = 10; body weight (BW = 44.8 +/- 1.45 kg), body condition score (BCS = 3.25 +/- 0.07)], and (ii) Control (Control, n = 12; BW = 45.30 +/- 1.32 kg, BCS = 3.33 +/- 0.06). Upon oestrus synchronization, the Beta group received 50 mg of beta-carotene per day during 35 days pre- and 17 days post-ovulation. The day 4, 8, 12 and 16 post-ovulation, blood samples were collected for quantification of serum P4 concentrations by radioimmmunoassay, and transrectal ultrasonographic scanning was performed at day 18 for evaluating CLT and VLT. Overall, CLT and VLT mean were 3.10 and 2211.1 mm(3) respectively. The Beta-goats depicted both the largest values for CLT (p = 0.07) and serum P4 levels (p = 0.05), with no differences (p = 0.53) for VLT between treatments. Results suggest a higher efficiency within the cellular-enzymatic groups defining the steroidogenic pathways in the beta-carotene-supplemented goats, generating a larger P4 synthesis. The last is essential for ovulation of healthy oocytes, maintenance of uterine quiescence, nourishment and survival of the embryo around implantation; all of them of paramount significance during the maternal recognition of pregnancy process.