Search

The research compares reproduction of female New Zealand White (NZW, n=55) and Californian (CAL, n=12) rabbits after mating with pure-bred Flemish Giant, Californian, and Burgundy Fawn males, as well as New Zealand White and Californian crossbred males. The influence of the dam’s breed, the birth season, and the parental component on reproduction parameters was analysed. Three groups of does were studied: those which had two litters (21 females), those which had three litters (15), and all does (irrespective of the number of litters, i.e. 67 females). In the first group, the mother’s breed was found to affect litter size at weaning (5.20 for Californian and 7.33 for New Zealand White), which was largest for the NZW×CAL crossbreed (10.50). Among the females with three litters, the breed of the dam influenced rearing efficiency, with greater efficiency noted for the New Zealand White breed (90.2%) than for the Californian breed (69.8%). Where all litters were considered, the two breeds differed in terms of the number of live-born kittens per litter (6.59 for NZW vs 7.71 for CAL) and litter size at weaning (6.34 vs 7.50). In this group, litter size at weaning was larger in winter (4.65) than in autumn (2.00). New Zealand White females that mated with Flemish Giant males produced fewer live-born kittens per litter (5.85) than Californian females that mated with Burgundy Fawn males (10.00). Pure-bred litters were smaller (2.04) at weaning than crossbred ones (from 5.39 to 10.00). For females with three litters, repeatability was 0.36 for total litter size and 0.35 for the number of live-born kittens per litter. For litter size at weaning, however, it was only 0.15, indicating a strong effect of environmental factors on rearing outcomes.

Enteric methane (CH4) is one of the main greenhouse gases emitted in livestock production systems with ruminants. Among the options to reduce such emissions, animal genetics is one of the factors that is taking relevance in recent years. The aim of the present study was to assess the emission of enteric CH4 in dairy cows with different genetic backgrounds. Sixteen cows belonging to the following three genetic groups were selected for this study: seven F1 (50% Jersey × 50% Gyr), five Triple cross (50% Jersey × 31% Holstein × 19% Sahiwal) and four Jersey. Enteric CH4 emissions were measured in all cows for 15 months, at the middle of each month, using the SF6 technique. Enteric CH4 emissions did not differ (p > 0.05) among genetic groups, although it varied with the stage of lactation, due to differences in milk yield and dry matter intake (DMI). Pasture DMI and the intensity of CH4 emissions (g kg−1 DMI) differed (p < 0.05) between dry and lactating cows, with higher DMI in the lactation period, while CH4 emission intensity was higher for dry cows. Cows with the highest proportion of Bos taurus genes presented a higher annual mean methane conversion factor (Ym), with 7.22, 7.05 and 5.90% for the Triple cross, purebred Jersey and F1, respectively. In conclusion, non-significant differences in enteric CH4 emissions and Ym were detected among dairy cows with different genetic backgrounds. However, F1 cows tended to show lower enteric CH4 emission and Ym, compared to those with more Bos taurus genes.

The aim of this work was to evaluate the effect of birth weight on the survival of Charollais, Kent and their crossbreds in breeding and also on their meat performance for Charollais and Kent lambs. Data were evaluated for the six years period in the commercial flock. The total number of lambs used for evaluation was 1,197. The data were passed through the SAS STAT program using the MIXED method. In the model equation, all the dependent variables of the survival indicator were significantly statistically detectable with a significance level of P < 0.01. The results indicated that survivability lambs was significantly influenced by birth weight and litter size (P < 0.05). Meat performance of lambs was affected the most combined year and month, breed and litter size (P < 0.05). The results suggest better survivability abilities for the crossbred than the pure-bred population. Despite the lack of meat performance data, it is interesting to consider a possible selection program for the breeds, Charollais and Kent, to improve the survival of lambs for extending extensive farming methods. However, also by improving flock management we will achieve better survivability results for lambs.

The partition of the total genetic variance into its additive and non-additive components can differ from trait to trait, and between purebred and crossbred populations. A quantification of these genetic variance components will determine the extent to which it would be of interest to account for dominance in genomic evaluations or to establish mate allocation strategies along different populations and traits. This study aims at assessing the contribution of the additive and dominance genomic variances to the phenotype expression of several purebred Piétrain and crossbred (Piétrain × Large White) pig performances. A total of 636 purebred and 720 crossbred male piglets were phenotyped for 22 traits that can be classified into six groups of traits: growth rate and feed efficiency, carcass composition, meat quality, behaviour, boar taint and puberty. Additive and dominance variances estimated in univariate genotypic models, including additive and dominance genotypic effects, and a genomic inbreeding covariate allowed to retrieve the additive and dominance single nucleotide polymorphism variances for purebred and crossbred performances. These estimated variances were used, together with the allelic frequencies of the parental populations, to obtain additive and dominance variances in terms of genetic breeding values and dominance deviations. Estimates of the Piétrain and Large White allelic contributions to the crossbred variance were of about the same magnitude in all the traits. Estimates of additive genetic variances were similar regardless of the inclusion of dominance. Some traits showed relevant amount of dominance genetic variance with respect to phenotypic variance in both populations (i.e. growth rate 8%, feed conversion ratio 9% to 12%, backfat thickness 14% to 12%, purebreds-crossbreds). Other traits showed higher amount in crossbreds (i.e. ham cut 8% to 13%, loin 7% to 16%, pH semimembranosus 13% to 18%, pH longissimus dorsi 9% to 14%, androstenone 5% to 13% and estradiol 6% to 11%, purebreds-crossbreds). It was not encountered a clear common pattern of dominance expression between groups of analysed traits and between populations. These estimates give initial hints regarding which traits could benefit from accounting for dominance for example to improve genomic estimated breeding value accuracy in genetic evaluations or to boost the total genetic value of progeny by means of assortative mating.

Objective The objective of the present study was to compare growth performance of Berkshire purebred pigs (BB), Hereford (HB) and/or Tamworth (TB) sired Berkshire crossbred pigs reared in a hoop structure in two experiments. Methods In the first experiment, BB was compared to TB while HB and TB were compared in the second. Body weights (BW) were recorded at 3 days of age and every 28 days from birth until 140 days of age. There was no significant difference between the BW of BB and TB, but HB was heavier than TB by 84 days of age. Least square means of average daily gain (ADG) were evaluated using one-way analysis of variance. Results The mean parity (±standard deviation) of the sows was 3.42±2.14 and a total of 45 farrowing occurred from year 2012 to 2014. The mean number of total born, number born alive, number of mummies, and number weaned were 9.23±2.52, 7.87±2.53, 0.04±0.21, and 5.94±2.74, respectively. Parity did not have a significant effect on the growth performance of the pigs. For BB and TB, there was only one time frame in which there was a significant difference in the ADG: between 28 and 56 days of age. For HB and TB, the overall ADG of HB was significantly greater than the total ADG of TB. Conclusion The breed of the sire did not affect the growth performance of the progeny between Berkshire purebreds and Tamworth×Berkshire crossbreds. The breed of the sire did have an effect between Hereford and Tamworth sired Berkshire crossbreds (p

Cutaneous evaporative heat loss in Bos indicus and Bos taurus has been well documented. Nonetheless, how crossbreds with different fractional genetic proportions respond to such circumstances is of interest. A study to examine the physiological responses to cutaneous evaporative heat loss, also lactation period and milk yield, were conducted in Sahiwal (Bos indicus, n = 10, 444±64.8 kg, 9±2.9 years), Holstein Friesian (Bos taurus, HF100% (n = 10, 488±97.9 kg, 6±2.8 years)) and the following crossbreds: HF50% (n = 10, 355±40.7 kg, 2±0 years) and HF87.5% (n = 10, 489±76.8 kg, 7±1.8 years). They were allocated so as to determine the physiological responses of sweating rate (SR), respiration rate (RR), rectal temperature (RT), and skin temperature (ST) with and without hair from 06:00 h am to 15:00 h pm. And milk yield during 180 days were collected at days from 30 to 180. The ambient temperature-humidity-index (THI) increased from less than 80 in the early morning to more than 90 in the late afternoon. The interaction of THI and breed were highly affected on SR, RR, RT, and ST (p0.05) but did change over time. The ST with and without hair were similar, and was higher in HF100% (37.4°C; 38.0°C) and their crossbred HF50% (35.5°C; 35.5°C) and HF87.5% (37.1°C; 37.9°C) than Sahiwal (34.8°C; 34.8°C) (p

The first aim of the study was to compare selected meat quality parameters in porkers without the gene RYR1T (ryanodine receptor gene). These were porkers slaughtered at 100 to 115 kg and 116 to 130 kg live weight. The second aim of the study was to determine the occurrence frequency of standard-quality meat (red, firm, nonexudative [RFN]) and the occurence frequency of defective meat (pale, soft, exudative [PSE] and acid, soft, exudative [ASE]). The analysis was conducted on the longissimus lumborum muscle in 114 crossbred porkers. The porkers were a cross of Camborough 22 sows and boars from lines 337PIC (Pig Improvement Company), Norsvin Landrace and Pietrain. All of the animals were provided with identical environmental and nutritional conditions. The average weight of the slaughtered animals in the light and heavy groups was 110 kg and 122 kg, respectively. Both groups had the same average post-slaughter meatiness (56.5%). A statistical analysis of selected meat-quality parameters did not show any significant differences between the weight groups. On the other hand, the classification based on carcass quality showed an occurence frequency of defective meat in heavier crossbred porkers (116 to 130 kg) that was three times higher than in those crossbred animals which weighed 100 to 115 kg when slaughtered. In porkers without the gene RYR1T, the defective meat types PSE and ASE occurred with a frequency of 17.54%.

The objective of this study was to establish the impact of crossing the indigenous Cres sheep with Awassi and, respectively, Awassi and East Friesian sheep on the milk yield and quality. For this purpose, through regular monthly milk yield recordings a total of 824individual milk samples from 139 sheep in the second lactation of the same flock were collected, of which: 46 purebred Cres sheep, CS; 33 crosses with 50 % Cres sheep and 50 % Awassi, CA; 60 crosses with 50 % Cres sheep, 25 % Awassi and 25 % East Friesian, CAEF. The obtained results show a significant (P

The analysis comprised purebred Charolais bull calves (CH) and crossbred bull calves born from Hereford (CH × HE) and Simmental (CH × SI) cows. Body weights and daily gains were measured in subsequent periods of the experiment and the post-slaughter evaluation was carried out. Carcass lean weight and dressing percentage were evaluated, as well as the lean content of five prime cuts. Total weight of the five prime cuts was measured and its share in the half-carcass weight was determined. The rib-eye area was also measured. The CH × SI crossbreds reached significantly higher body weights at weaning, 210-day body weights and weights at finishing, as well as significantly higher daily gains in all the periods (P < 0.05, P < 0.01) and were characterized by the heaviest carcasses and most cuts, particularly the round. The crossbreds had the highest total weight of five prime cuts and total lean weight, highest weight of the round and lean weight in the round. Other relationships were found analyzing the share of each cut in the carcass. The share of tenderloin and rump in the carcass of CH × SI was significantly lower compared to the purebred bulls (P < 0.01) and CH × HE (P < 0.05). They also had a significantly lower share of the shoulder, shank and shin, as compared to the other groups, as well as a significantly higher (P < 0.05) share of the neck, as compared to the purebred bulls. The purebred bulls also achieved good results and had the highest share of the prime cuts and the largest mean rib-eye area.

Two experiments were conducted to investigate the birds’ responses to diets of varying nutrient concentrations, one with 126 eight-week old F1 crossbred (Rhode Island Red male×Fayoumi female) birds up to 20 weeks of age (growing stage) and another with ninety 20-week-old birds up to 22 weeks (pre-layer stage) under semi-scavenging condition in the poultry farm. Dietary treatments consisted of an arrangement of three diets that contained 14% crude protein (CP) and 2550kcal metabolizable energy (ME)/kg (low nutrient density ; LND), 15% CP and 2750kcal ME/kg (moderate nutrient density ; MND) and 16% CP and 2950kcal ME/kg (high nutrient density ; HND). The contents of CP, ME and calcium (Ca) in MND diet were fitted with the requirements calculated in this experiment based on five nutrient specifications in the world. All diets were formulated using locally available conventional feedstuffs and un-conventional feed ingredients employing a free software of computer program for least-cost feed formulation. The responses of grower birds to different diets showed that the highest body weight and live weight gain were achieved by the birds that received HND diet that differed significantly from those of LND diet (p

A random sample of 40 goats was used to study the partitioning, yield and composition of milk: 8 of Saanen breed (S), 8 of Damascus breed (D), 8 crossbreds Saanen × Local Greek goat (S × L), 8 backcrosses Saanen × Local Greek goat {(S × L) × S} and 8 crossbreds Saanen × Alpine (S × A). Four dams of each genotype were of the first and four of the second parity. Goats were milked twice daily (8:00, 18:00 h) in a 1 × 12 side by side milking parlour with 6 milking units. Milk yield and milk fractions (machine milk, machine stripped milk and hand stripped milk) were recorded twice daily each 14 days (from 7th-8th to 29th week of lactation). Milk composition was examined once a month separately for morning and afternoon samples. The ponderable mean was used for the calculation of milk fat, protein and lactose percentage. The results of the experiment showed that milk partitioning in purebred and crossbred goats ranged on satisfactory levels (machine milk - MM: morning 69.8-81.6%, afternoon 66.2-77.4%; machine stripping milk - MSM: morning 12.2-19.3%, afternoon 19.2-23.4%; hand stripping milk - HSM: morning 6.1-10.9%, afternoon 5.4-11.9%; total machine milk - TMM: morning 89-94.6%, afternoon 88-94.6%). The effect of breed (crossbred) was found to be significant for all milk fractions (ml and %, P < 0.001 and P < 0.05, respectively). The effect of parity was significant except for MSM (%) and HSM (%). The effect of lactation stage (control day) and the animals was also found to be significant (P < 0.001). The fat percentage of S, D, S × L, S × A and (S × L) × L was 3.82, 5.1, 4.8, 3.88 and 3.95%, respectively (P < 0.001). Protein percentage ranged from 3.1 to 3.6% in the different genotypes (P< 0.001) while lactose percentage was from 4.51 to 4.66%. In conclusion it may be said that imported dairy goat breeds and different crosses with local Greek breed are characterized by good milkability. So the best technique of machine milking is the "routine" milking without applying hand stripping.

Foram avaliadas as características das partes não-integrantes da carcaça de novilhos 5/8 Nelore 3/8 Charolês terminados em confinamento e abatidos com 425, 467 e 510 kg. Os períodos de alimentação foram 30, 65 e 94 dias, respectivamente. A idade e peso médio iniciais foram de 660 dias e 361 kg, respectivamente. A dieta alimentar, com relação volumoso:concentrado de 60:40 com base na matéria seca (MS), continha 10,25% de proteína bruta e 3,18 Mcal de energia digestível/kg MS. De acordo com estimativa da equação de regressão, os rendimentos de carcaças quente e fria elevaram com o aumento no peso de abate (P). No entanto, quando expressos por peso de corpo vazio (PCV), houve similaridade entre os diferentes tratamentos. Quando os componentes foram expressos em valores absolutos, couro, total de componentes externos (TCE), fígado, total de órgãos vitais (TOV), total de gorduras internas (TGORD) e total de trato gastrintestinal vazio (TGVZ) apresentaram incremento com o aumento no P. Quando expressos por 100 kg de P e PCV, os componentes couro, TCE, fígado e TGVZ apresentaram similaridade; coração e TOV, decréscimo; e TGORD, acréscimo, com o aumento no P. Houve correlação positiva entre peso de fígado com consumo de matéria seca (r = 0,91) e com energia líquida de mantença (ELm) (r = 0,91) e entre TGORD com ELm (r = 0,78).The characteristics of the body parts non-integrant of the carcass of 5/8 Nellore 3/8 Charolais steers feedlot finished and slaughtered with 425, 467 and 510 kg, were evaluated. The feeding periods were 30, 65 and 94 days, respectively. The average initial age and weight were 660 days and 361 kg, respectively. The diet, with 60% roughage and 40% concentrate dry matter basis (DM), contained 10.25% of crude protein and 3.18 Mcal of digestible energy/kg DM. According to regression equation estimate, the hot and cold carcass dressing increased as slaughter weight (SW) increased. However, when expressed per empty body weight (EBW), similarity among the different treatments was verified. When the components were expressed in absolute values, rawhide, total external components (TEC), liver, total vital organs (TVO), total internal fats (TFAT) and total empty gastrintestinal tract (TEGT) showed increase with increase in SW. When expressed per 100 kg of body weight and EBW, the rawhide, TEC, liver and TEGT components showed similarity; heart and TVO showed decrease; and TFAT showed increase, with increase in SW. Positive correlations between liver weight with dry matter intake (r=.91) and with net energy maintenance (NEm) (r=.91), and between TFAT with NEm (r=.78) were observed.

The aim of our study was to evaluate the effects of chosen factors (crossbreds, sex, litter size, age of ewes and interaction between sex and litter size) on the growth of lambs crossbreds of the breeds Charollais (Ch), Suffolk (Sf) and Improved Valachian (IV). The evaluation was performed in the year 2004 on the farm Růžďka and involved altogether 96 lambs. The growth ability was evaluated at the following crossbreds: Ch x Sf (n = 28), (Ch x Sf) x Sf (n = 28), IV x Sf (n = 21) and (IV x Sf) x Sf (n = 19). All lambs under study were born indoor in January. Lambs were kept indoor till the end of the evaluation. From the evaluation of effects of crossbreds, sex and age of ewes on the live body weights and daily gains of lambs above all result that these factors showed a significant effect only on the live body weight at birth. On the other hand, the factors of litter size and interaction between sex and litter size showed a highly significant (P < 0.01) effect on the live body weights of lambs at birth, at 70 and at 100 days of age as well as on their daily gains within the intervals from birth to 70 and 100 days of age. It can be concluded that the daily gains were highly uniform but relatively low in all crossbreds under the study within the time interval from birth to the age of 100 days, while the non-significantly highest daily gain was recorded in the crossbreds of IV x Sf (211 g). On the other hand the lowest ones were observed in the crossbreds of CH x Sf and (IV x Sf) x Sf (199 g).

Linkage disequilibrium (LD) and the persistence of its phase across populations are important for genomic selection as well as fine scale mapping of quantitative trait loci. However knowledge of LD in beef cattle, as well as the persistence of LD phase between crossbreds and purebreds, is limited. The objective of this study was to understand the patterns of LD in Angus, Charolais, and crossbred beef cattle based on 31’073, 32’088 and 33’286 SNP in each population, respectively. Amount of LD decreased rapidly from 0.29 to 0.23 to 0.19 in Angus (AN), 0.22 to 0.16 to 0.12 in Charolais (CH), 0.21 to 0.15 to 0.11 in Crossbreds (C), when the distance range between markers changed from 0-30kb to 30-70kb and then to 70-100kb, respectively. Breeds and chromosomes had significant effects (P