Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Factors affecting somatic cell count in dairy goats: a review
Get PDFSomatic cell count (SCC) in monitoring udder health has been described in numerous studies as a useful method for the diagnosis of intramammary infection (IMI), and it is considered in standards of quality and hygiene of cow’s milk in many countries. However, several authors have questioned the validity of SCC as a reliable IMI diagnosis tool in dairy goats. This review attempts to reflect the importance of different infectious and non-infectious factors that can modify SCC values in goat milk, and must, therefore, be taken into account when using the SCC as a tool in the improvement of udder health and the quality of milk in this species. In dairy goats, some investigations have shown that mammary bacterial infections are a major cause of increased SCC and loss of production. In goats however, the relationship between bacterial infections and SCC values is not as simple as in dairy cattle, since non-infectious factors also have a big impact on SCC. Intrinsic factors are those that depend directly on the animal: time and number of lactation (higher SCC late in lactation and in aged goats), prolificity (higher SCC in multiple births), milking time (higher SCC in evening compared to morning milking) and number of milkings per day, among others. Extrinsic factors include: milking routine (lower SCC in machine than in manual milking), seasonality and food. In addition, milk secretion in goats is mostly apocrine and therefore characterized by the presence of epithelial debris or cytoplasmic particles, which makes the use of DNA specific counters mandatory. All this information is of interest in order to correctly interpret the SCC in goat milk and to establish differential SCC standards
Predictive ability of machine learning methods for massive crop yield prediction
Get PDFAn important issue for agricultural planning purposes is the accurate yield estimation for the numerous crops involved in the planning. Machine learning (ML) is an essential approach for achieving practical and effective solutions for this problem. Many comparisons of ML methods for yield prediction have been made, seeking for the most accurate technique. Generally, the number of evaluated crops and techniques is too low and does not provide enough information for agricultural planning purposes. This paper compares the predictive accuracy of ML and linear regression techniques for crop yield prediction in ten crop datasets. Multiple linear regression, M5-Prime regression trees, perceptron multilayer neural networks, support vector regression and k-nearest neighbor methods were ranked. Four accuracy metrics were used to validate the models: the root mean square error (RMS), root relative square error (RRSE), normalized mean absolute error (MAE), and correlation factor (R). Real data of an irrigation zone of Mexico were used for building the models. Models were tested with samples of two consecutive years. The results show that M5-Prime and k-nearest neighbor techniques obtain the lowest average RMSE errors (5.14 and 4.91), the lowest RRSE errors (79.46% and 79.78%), the lowest average MAE errors (18.12% and 19.42%), and the highest average correlation factors (0.41 and 0.42). Since M5-Prime achieves the largest number of crop yield models with the lowest errors, it is a very suitable tool for massive crop yield prediction in agricultural planning
The extent of increase in first calving age as a result of implementing various sexed semen breeding strategies
Get PDFA deterministic simulation was conducted to assess the effects of sexed semen utilization strategies on age at first calving (AFC). Four different strategies were implemented on dairy heifers: continuous use of conventional semen only (CC), continuous use of sexed semen only (SS), utilization of sexed semen for both the first and second services with conventional semen afterwards (S2), and utilization of sexed semen for the first service with conventional semen afterwards (S1). Results indicated that continuous utilization of sexed semen led to the greatest AFC; however at high conception rates, strategies displayed negligible differences on AFC. Increases in estrus detection rate had the greatest effects on decreasing AFC of the SS scenarios. Negative effect of sexed semen on AFC increased when the effect of low estrus detection rate was combined with low conception rate of sexed semen. Results indicated that in the case of access to sexed semen conception rate, prediction of AFC is possible by quadratic polynomial or exponential equations, depending to the applied breeding strategy. Simultaneous utilization of sexed and conventional semen in a herd did not make a substantial change in AFC when a low percentage of sexed semen was employed. Increasing the contribution of different sexed semen strategies led to higher AFC variation, especially for the SS strategy. AFC of strategies that utilize sexed semen is highly dependent on the conception rate, estrus detection rate and the contribution of sex sorted semen in the total number of inseminations of the heifer herd
Short communication. Effects of the time to change from incubation to hatching temperature on the artificial incubation of red-legged partridge (Alectoris rufa) eggs
No full textThis study investigates, in red-legged partridge (Alectoris rufa), the effects of the time to change from incubation to hatching temperature on egg weight loss, hatchability, chick weight at hatch, incubation length, and development stage at embryonic mortality. Five batches of 80 eggs each were incubated at 37.8ºC during the first 18, 19, 20, 21 or 22 d of incubation, and subsequently at 37.5ºC until hatching. Hatchability, development stage at embryonic mortality and chick weight at hatch were not affected by the time of temperature change (p > 0.05). However, incubation length and egg weight loss after 21 d of incubation as representative of that of developed embryos were influenced by the incubation treatment (p<0.001 and p<0.05, respectively). Thus, eggs maintained at the incubation temperature of 37.8ºC for 22 d not only hatched earlier (23.04 d) but also with lower dispersion than eggs from the other treatments. As hatching may start around day 22 of incubation, to improve hatching synchrony we could recommend to move A. rufa eggs from the incubator, set at 37.8ºC, to the hatcher on the 21st d of incubation keeping the temperature unchanged, and reduce it to 37.5ºC on the 22nd d. Nevertheless, further research should be carried out to study the effect of this temperature scheduling on chick growth and performance
Effect of different levels of raisin waste on performance, nutrients digestibility and protozoal population of Mehraban growing lambs
Get PDFThe aim of this study was to assess the effects of different inclusion levels of raisin waste (RW) in the diet on the animal performance and ruminal fermentation parameters of growing lambs. Four levels of RW inclusion (i.e., R0, R1, R2 and R3 for 0, 100, 200 and 300 g RW kg-1 dry matter of diet, respectively) were tested. The experimental diets were fed to 24 male lambs (six months old) and six animals were allocated to each treatment. In the first experiment, effects of different levels of RW on the animals’ performance, some rumen parameters and protozoa populations were studied. In the second experiment, the apparent total tract digestibility of diets and nitrogen balance were measured. The highest final body weights were observed for the R2 and R3 diets. The R3 diet had the lowest dry matter intake (1156 vs. 1303 g day-1 for R3 and R0, respectively) and feed conversion rate (6.4 vs. 8.7 for R3 and R0, respectively). Total number of protozoa increased with the addition of RW, but Epidinium spp. completely disappeared with the R3diet. Inclusion of RW at levels higher than 200 g RW kg-1 DM of diet significantly reduced crude protein (p=0.042) and neutral detergent fiber digestibility (p=0.049). Our findings showed that RW could be included in the diets of growing lambs up to 200 g kg-1 DM without compromising their production performance
GIS-based assessment of land suitability for alfalfa cultivation: a case study in the dry continental steppes of northern China
Get PDFAlfalfa (Medicago sativa L.) is the most valuable perennial forage grass in northern China. We selected 12 ecological criteria and 4 socioeconomic criteria to calculate the suitability of land for alfalfa cultivation in the Xilingol League of the Inner Mongolia Autonomous Region. We combined ecological suitability assessment with fuzzy analysis to standardize the criteria. We used the analytical hierarchy process to determine the weight of these criteria, and used multi-criterion decision analysis (MCDA) to aggregate the criteria. We then calculated the suitability score for each evaluation unit. The suitability was divided into highly, moderately, and marginally suitable, or unsuitable, using the geoprocessing module of ArcGIS 9.3 according to the FAO land suitability classification. We found that highly suitable areas covered 10,799.84 km2, accounting for 5.3% of the total area, and unsuitable areas covered 99,235.87 km2, accounting for 48.9% of the total area. Combining the fuzzy analysis method with the theory of ecological suitability and the MCDA method to evaluate the suitability of land for alfalfa cultivation provided insights that can guide decisionmakers and farmers to make more practical and scientific decisions
Deep percolation in greenhouse-cultivated celery using the technique of subsurface film strips placement
Get PDFTo reduce the deep percolation during greenhouse vegetable cultivation, the technique of subsurface film strips placement was tested. Four treatments with two kinds of cross-sections (flat and U-shaped) and two different spacings (10 cm and 40 cm) of subsurface film strips were arranged in a greenhouse before planting celery. At the same time, a non-film treatment was arranged for comparison. Soil water content was measured and irrigation time was adjusted according to the soil water content. Evapotranspiration of celery during growth was calculated by the method of energy balance and the deep percolation was calculated by the equation of water balance. Deep percolation was reduced in all experimental treatments. Greater reduction in deep percolation was observed when using U-shaped cross-section strips compared with that using the flat cross-section strips. In addition, greater reduction in deep percolation was observed when the spacing between the film strips was smaller. The results of this test showed that the technique of subsurface film strips placement can reduce deep percolation and conserve irrigation water for greenhouse vegetables cultivation. However, the optimal layout variables for the use of the technique of subsurface film strips placement need further experimental and numerical analysis
Carcass and meat quality traits of Celta heavy pigs. Effect of the inclusion of chestnuts in the finishing diet
Get PDFCarcass and meat quality traits were studied in 36 Celta pigs (a breed native from NW of Spain) reared for 16 months in an extensive regime and slaughtered at a live weight of around 170 kg. The effect of partially or totally replacing commercial compound feed with chestnuts in the finishing diet was also investigated. Celta heavy pigs were characterised by high killing out, subcutaneous fat thickness, and ham length values, and by low ham perimeter, and Longissimus lumborum muscle area values. Meat showed high myoglobin contents and a* values, and very high hardness. By increasing the proportion of chestnuts in the finishing diet the quantity of back fat increased and the pH of the meat decreased. However, neither these effects, nor any of those on the other traits studied were statistically significant. The absence of significant effects may be due to the fact that pigs fed with chestnuts were not subjected to feed restrictions
Lack of relationship between Visna/maedi infection and scrapie resistance genetic markers
Get PDFThe relationship between Visna/maedi virus (VMV) antibody status and scrapie genetic resistance of 10,611 Rasa Aragonesa sheep from 17 flocks in Aragón (Spain) was investigated. The fifteen most common PRNP gene haplotypes and genotypes were identified and the genotypes were classified into the corresponding scrapie risk groups (groups 1 to 5). ARQ (93.3%) and ARR (31.8%) were the most common haplotypes and ARQ/ARQ (56%) and ARR/ARQ (25.6%) were the most common genotypes. The frequencies of scrapie risk groups 1, 2, 3, 4 and 5 were 3.3%, 27.3%, 63.5%, 1.2% and 4.8%, respectively. Overall Visna/maedi seroprevalence was 53% and flock seroprevalence ranged between 21-86%. A random effects logistic regression model indicated that sheep VMV serological status (outcome variable) was not associated with any particular scrapie risk group. Instead, VMV seropositivity progressively increased with age, was significantly greater in females compared to males and varied between flocks. The absence of a relationship between VMV infection and scrapie genotypes is important for VMV control and specifically for sheep participating in an ELISA-based Visna/maedi control program
Evolution of udder morphology, alveolar and cisternal milk compartment during lactation and their relationship with milk yield in Najdi sheep
Get PDFA total of 30 multiparous Najdi ewes were used to study the evolution of udder morphology traits and milk fractions in the udder during suckling (3rd, 6th, 9thwk) and milking (10th, 11th, 12thwk) periods. During suckling period, daily milk yield was estimated by using the double oxytocin injections method 4-h after milking. During milking period, ewes were hand-milked once daily. Udder and teat morphology traits for all ewes were measured 4-h after milking. Udder compartments were evaluated 8-h after milking by using atosiban and oxytocin; milk samples of each fraction were collected. Najdi ewes had a medium and healthy udders (CMT<1), with medium sized teats (length, 3.2±0.1 cm and width, 1.7±0.1 cm) attached at 35.7 ± 11º angle. Milk yield averaged 1.88±0.18 and 0.44±0.12 L d-1 during suckling and milking periods, respectively. A drop in milk yield (-75%, p<0.01) was found in the transition from suckling to milking. Udder traits, teats angle and width, and distance between teats declined (p<0.05) throughout lactation, whereas teat lengths did not show any change. Positive correlations (p<0.05) were observed between milk yield and udder depth (r=0.47-0.49), width (r=0.31-0.39) and distance between teats (r=0.26-0.39). The cisternal milk volumes decreased (p<0.05) after weaning, whilst the corresponding percentages increased (p<0.05). Cisternal milk accounted for 55% and 67% of the total udder milk during suckling and milking periods, respectively. Cisternal milk was positively correlated (r=0.93, p<0.05) with total milk yield. The percentages of protein and total solids in alveolar and cisternal milk increased significantly (p<0.05) after weaning, whilst fat percentages in cisternal milk did not change. In conclusion, the evaluated Najdi ewes showed medium sized cisterns and teats, which considered adequate for machine milking. Udder morphology traits had positive correlations with milk yield and hence, can be utilized in breeding programs