L. A. Bermejo

Population structure of eleven Spanish ovine breeds and detection of selective sweeps with BayeScan and hapFLK.

The goals of the current work were to analyse the population structure of 11 Spanish ovine breeds and to detect genomic regions that may have been targeted by selection. A total of 141 individuals were genotyped with the Infinium 50 K Ovine SNP BeadChip (Illumina). We combined this dataset with Spanish ovine data previously reported by the International Sheep Genomics Consortium (N = 229). Multidimensional scaling and Admixture analyses revealed that Canaria de Pelo and, to a lesser extent, Roja Mallorquina, Latxa and Churra are clearly differentiated populations, while the remaining seven breeds (Ojalada, Castellana, Gallega, Xisqueta, Ripollesa, Rasa Aragonesa and Segureña) share a similar genetic background. Performance of a genome scan with BayeScan and hapFLK allowed us identifying three genomic regions that are consistently detected with both methods i.e. Oar3 (150–154 Mb), Oar6 (4–49 Mb) and Oar13 (68–74 Mb). Neighbor-joining trees based on polymorphisms mapping to these three selective sweeps did not show a clustering of breeds according to their predominant productive specialization (except the local tree based on Oar13 SNPs). Such cryptic signatures of selection have been also found in the bovine genome, posing a considerable challenge to understand the biological consequences of artificial selection.

Productivity: key factor affecting grazing exclusion effects on vegetation and soil

In this study, we inquire into the effects of short-term goat grazing abandonment on plant species and functional composition, bare ground and net primary productivity (NPP) in two traditionally grazed pastures located in the Canarian Network of Natural Protected Areas and the Natura 2000 Network. In addition, we analyse soil chemical properties, biomass tannin content and energetic value to find out how grazing abandonment affects soil fertility and forage quality of these agroecosystems. Grazing exclusion effects on plant species and functional composition, as well as on soil fertility depended on the productivity of the studied pasture. Erect forbs and shrubs (endemic to Macaronesian region and native) were favoured by grazing removal in the most productive pasture, while soil fertility decreased in the driest and least productive site. An increase in NPP after exclusion was consistent among study sites. Although we consider goat grazing as necessary for maintaining traditional agroecosystems, we also suggest controlling it over time, allowing some periods of rest to give endemic shrub species time to recover from near propagule sources.

Factors influencing birth and weaning weight in Canarian hair lambs.

Abstract Bermejo, L.A., Mellado, M., Camacho, A., Mata, J., Arévalo, J.R. and de Nascimento, L. 2010. Factors influencing birth and weaning weight in Canarian hair lambs. J. Appl. Anim. Res., 37: 273–275. The influence of year and season of birth, parity of dam, type of birth and sex of lamb on growth traits of Canarian hair lambs was examined using data on 3206 Canarian lambs from 1508 dams and 44 sires raised in the Tenerife Island. Ram lambs had higher (P<0.001) birth weight (BW), 60-d weaning weight (WW) and pre-weaning daily weight gain than ewe lambs. Season had no effect on birth weight but WW was the lowest in winter. BW, WW and preweaning daily gain were highest in single born lambs. Parity had no definite effect on any of the studied parameters.

Thermoregulatory responses related to coat traits of Brazilian native ewes: an adaptive approach

ABSTRACT Semi-arid conditions can adversely affect livestock productivity and change certain physiological parameters. The relationship between hair coat and thyroxine levels in Morada Nova ewes was evaluated through environmental factors, such as air temperature, relative air humidity, radiant and Black Globe Humidity Index to gain a better understanding of thermoregulation mechanisms in these animals. Measurements were taken from July to January in 383 Morada Nova ewes. The variables studied included rectal temperature (RT), respiratory rate (RR), coat thickness (CT), hair length (HL), hair diameter (HD), hair density (D) and thyroid hormones. The data underwent multivariate statistical analyses and a significant inverse relationship was found between coat traits and Thyroxine (T4). The animals that exhibited greater HL, coat density and CT showed lower T4 concentrations. Coat traits showed a strong interaction with physiological mechanisms and can be considered relevant in maintaining homeostasis. Hair traits play an important role in this process, since T4 reduction was stronger in animals that showed difficulties in eliminating heat, which were the ones that had greater HL, hair density and HD. By contrast, animals with a hair coat more favourable to heat losses had higher levels of thyroid hormones.

Meat quality of lambs (hair and wool) slaughtered at different live weights

ABSTRACT In this research the meat quality of the two canary sheep local breeds, Canaria breed (CB) and Canaria Hair breed (CHB), was evaluated, making groups of 10 males and females from each, slaughtered at live weights of 9.78 ± 0.49 kg, 15.8 ± 0.66 kg and 24.9 ± 0.76 kg. The breed affected to meat and fat colour at 24 h after slaughter. Meat of CB showed more redness and more chroma values. Fat of CB showed greater lightness. Related to the physio-chemical analysis of the meat, CB showed higher water-holding capacity, shear force and intramuscular fat content that CHB; however, CHB showed higher protein and ash percentages that CB. In relation to fat quality, CB presented higher MUFA percentage and CHB had higher PUFA percentage. CHB showed the lower atherogenic and thrombogenic indexes. Slaughter weight affected the pH, meat and fat colour and also all physio-chemical parameters, except shear force and collagen content and the fatty acid profile. Males had higher moisture content, soluble collagen and PUFA, while females had higher MUFA. The breed effect on meat quality was shown mainly in lambs slaughtered at 10 kg. Owing to their fatty acid profile, the healthiest meat was from lambs slaughtered at 25 kg.

Effect of breed (hair and wool), weight and sex on carcass quality of light lambs under intensive management

Eighty carcasses of Canaria Hair breed (CHB) and Canaria breed (CB) were evaluated; 10 carcasses by sex, breed and slaughter weight (15.8 ± 0.66 kg and 24.9 ± 0.76 kg live weight, respectively). Breed effect was observed in measurements, fatness, commercial category and tissue composition of the carcass. CHB presented carcasses with more leg length and rump perimeter (but only in 25 kg lambs), heaviest shoulder and more muscle percentage. CB showed carcasses more fatness (8.18 ± 1.66 vs. 6.63 ± 1.46) and with more fat depth (3.90 ± 1.35 vs. 2.86 ± 1.15). CB increases its fatness faster because 16 kg lambs of CB showed similar values that 25 kg lambs of CHB (7.45 vs. 7.26, respectively). All carcass measurements, conformation, compactness indices and carcass fatness were affected by weight; 25 kg lambs showed higher values. Weight effect was also found in the tissue composition; 25 kg lambs showed more intermuscular fat (IF) percentage and less bone percentage. Sex effect was observed in first category joints, in total fat and IF; females showed higher percentages than males. In relation to carcass quality, we conclude that CB could be more commercially attractive in light carcasses because this breed increases its fatness faster and CHB more commercially attractive in heavy lambs.

Factors Affecting Days to Conception, Litter Size and Litter Weight of Intensively Managed Canarian Hair Sheep

Abstract Bermejo, L.A., Mellado, M., Mata, J., Arévalo, J.R., Nascimento, L.D. and Camacho, A. 2010. Factors affecting days to conception, litter size and litter weight of intensively managed Canarian hair sheep. J. Appl. Anim. Res. 37: 261–264. In order to assess the effect of month of breeding, year and sire on days to conception, litter size and litter weight, records on 605 lambings by 350 ewes and 13 rams were used. Days to conception were higher (P<0.01) for spring and summer breeding than mating in fall and winter. Sixty-nine percent of ewes became pregnant within 10 d of ram exposure in winter compared with 24% in spring (P<0.01). Litter size at birth tended (P=0.08) to be higher for spring breeding and lower in winter matings. Mean litter weights at birth were influenced by year of lambing and ram (P<0.01), but not by breeding season. It was concluded that the Canarian hair sheep can be used in accelerated lambing systems under intensive conditions found in the Canary Islands, because this breed presents only a mild reproductive seasonality, which allows multiple-season lambings.

Expression patterns and genetic variation of the ovine skeletal muscle transcriptome of sheep from five Spanish meat breeds

The goal of the current study is to analyse the gene expression profile of the ovine skeletal muscle as well as to characterize the genetic variation of transcripts expressed in such tissue. This aim has been achieved by sequencing the longissimus dorsi transcriptomes of 50 sheep distributed in five pools representing the Canaria de Pelo, Roja Mallorquina, Gallega, Xisqueta and Ripollesa Spanish autochthonous breeds. Approximately, 363 million reads per pool have been produced and 71.9–82.9% have been successfully mapped to the ovine genome in a paired-end mode (2 × 75 bp). The 200 most expressed muscle transcripts (≈1% of the total transcript count) account for 51% (Canaria de Pelo) to 67% (Gallega) of the total ovine skeletal muscle mRNA expression. These highly expressed genes play key roles in pathways related with striated muscle contraction, gluconeogenesis, glycolysis, citric acid cycle and respiratory electron transport. RNA-Sequencing of muscle transcripts has also revealed that ~72% of the SNPs detected with this approach are shared by at least two pools, and 10% of them segregate in the five pools under analysis. Most of the substitutions detected by RNA-Seq are synonymous or missense and only a minority are predicted to have consequences on protein function.

Efecto de la raza, peso de sacrificio y sexo en el quinto cuarto en razas ovinas canarias

Sixty Canaria lambs and 60 Canaria Hair breed lambs (half male and half female), slaughtered to 9.78±0.49, 15.8±0.66 and 24.9±0.76 kg live weight were studied. The objective of study was to determine the effect of breed, slaughter weight and sex of lamb on percentages of fifth quarter and their components. Canaria breed lambs showed a higher weight for fifth quarter, and its percentage of edible organs was lower than in Canaria Hair breed. The intestines, skin and head were the parts that had greater weight percentage. The importance of the fifth quarter was reduced when slaughter weight increased due to lower percentage of head and legs. Males showed higher values for head, legs and bladder; females showed higher values for the skin. Skin percentage increased when increasing the slaughter weight only in wool lambs.

Effect of breed (wool and hair) and sex on the carcass quality of suckling lambs under intensive management

Carcasses of twenty lambs (10 males and 10 females) from the Canaria Hair breed (CHB) and another twenty (10 males and 10 females) from the Canaria breed (CB) of 9.91±0.73 kg and 9.87±0.80 kg live weight, respectively, were studied. In the principal component (PC) analysis, the projection of carcass measurement data in the first PC allowed for clearly distinguishing between CB and CHB. In the analysis of variance, breed effect was observed in the morphology of the carcass: CB lambs showed the longest carcasses and CHB lambs showed the widest carcasses. Due to their wider rump and shorter legs, CHB lambs presented a more compact leg index. The carcasses from Canaria lambs had the highest fat score, the heaviest shoulder and the highest total fat percentage. The carcasses from CHB lambs showed a higher lean percentage. The carcass yield, conformation, degree of fatness and tissue composition were similar in both sexes. However, significant differences in the commercial cut yield were observed: males showed heavier shoulders than females. The effect of sex on carcass quality is unimportant. The breeds are different in important characteristics for the market, such as fatness. This fact is of significant interest because it diversifies the offer and means that different markets can be satisfied.