The content of beta-carotene, vitamin A and ascorbic acid in different tissues of bulls, short-scrotum bulls and oxen of different body weights]

Analyses of the liver of bulls of different age show, that the concentration of beta-carotene in the age of 6 to that of 25 weeks increased only from 0.43 +/- 0.16 to 1.66 +/- 0.27 and that of vitamin A from 11.49 +/- 5.87 to 13.90 +/- 5.21 micrograms/g fresh weight. The concentration of beta-carotene and of vitamin A in the testis of bulls and of short scrotum bulls up to an age of 15 weeks was similar; thereafter the concentration in the short scrotum bulls was higher. At an age of 72 weeks the concentration of vitamin A in the liver of bulls (219.17 +/- 51.86) was higher (p less than 0.01) than in that of the short scrotum bulls (144.11 +/- 27.79) and that of the oxen (135.51 +/- 41.26 micrograms/g fresh weight). Analyses of the concentration of ascorbic acid in 8 different tissues of bulls and short scrotum bulls at 6 various periods show, that the highest values mostly were found in December.     

Bulk and trace elements in the accessory glands of buffalo bulls.

Little is known of the importance of mineral levels in buffalo semen or the relationship of the level of various elements to spermatozoan activity. To establish a basis upon which further studies could be conducted, the accessory glands (seminal vesicles, prostate and bulbo-urethrals) of 43 buffalo bulls (2-4 years old) with intact testes and eight steers (3-4 years old) were analysed for their content of bulk and trace elements. The ash obtained from known weights of various accessory glands was used to determine the concentrations of Na and K using emission flame photometry. P was determined chemically, whereas Ca, Mg, Cu, Fe and Zn were assayed by atomic absorption spectrophotometry. The accessory glands of intact bulls varied significantly in the concentration of all elements except Fe. Ca and Cu were relatively more concentrated in the seminal vesicles. The prostate had the highest concentration of Zn, while the highest concentrations of Na, K, Mg and P were found in the bulbo-urethral glands. Age of the bulls had no marked effect on any of the elements studied except Cu which appeared to decrease significantly in older bulls. Seasonal variation was significant for the levels of K, Ca and Zn. Castration appeared to result in a highly significant reduction of Zn concentration in all accessory glands.     

Relationships of metabolic hormones and serum glucose to growth and reproductive development in performance-tested Angus, Brangus, and Brahman bulls

Understanding mechanisms that regulate growth and reproduction are important for improving selection strategies in cattle. In this study, Angus, Brangus, and Brahman bulls (n = 7 per breed) of similar age were selected from a group of 65 weanlings. Bulls were evaluated after weaning (i.e., approximately 6 mo of age) for 112 d for serum concentrations of metabolic hormones and glucose, growth, and reproductive traits. Performance data and blood sera were collected on d 0, 28, 56, 84, and 112. Sera were also collected in periods from d 50 to 59 (56D) and 103 to 112 (112D). Angus bulls were heavier (P < 0.05) throughout the study than Brahman bulls and were heavier than Brangus bulls on d 56, 84, and 112. Initial and final BW for Angus, Brangus, and Brahman bulls were 292.7, 260.6, and 230.4 and 468.3, 435.6, and 350.7 +/- 12 kg, respectively. Conversely, Brahman bulls had greater hip height (P < 0.05) than Brangus, and Brangus were taller (P < 0.05) than Angus. Angus bulls had the greatest (P < 0.05) scrotal circumference (SC) and Brahman bulls the least. Mean SC across days was 31.5, 29.7, and 25.0 +/- 0.6 cm for the three respective breeds. Serum testosterone was greater (P < 0.01) in Angus and Brangus bulls (10.0 and 8.9 +/- 1.4 ng/mL) than in Brahman bulls (4.0 +/- 1.4 ng/mL) throughout the study. After d 112, 100, 86, and 57% of the Angus, Brangus, and Brahman bulls passed a breeding soundness exam (P = 0.51). Serum concentrations of IGF-I and leptin were greater (P < or = 0.06) in Angus bulls on d 56, 84, and 112 than in Brangus and Brahman bulls. Serum concentrations of GH (P < 0.08) and glucose (P < 0.03) were greater in Brangus bulls than in Angus or Brahman bulls throughout the study. Prediction analyses suggested that serum concentrations of leptin could be used to predict (P < or = 0.08) BW and SC (R2 > 0.82) in the 56D and 112D periods among these breeds. Leptin was also useful in predicting (P < or = 0.09) serum concentrations of GH and testosterone in the 112D period (R2 > 0.32). Residual correlation analyses with the effect of breed removed suggested that leptin was correlated (r > or => 0.53, P < 0.05) with both SC and serum testosterone. Angus and Brahman cattle differ in phenotype, level of adiposity, and rate of sexual development. Data herein suggest that these characteristics could be due to varying mechanisms by which metabolic hormones such as leptin, GH, and(or) IGF-I are regulated.     

Observations on spiral deviation of the penis in beef bulls

Premature spiral deviation of the penis was investigated in 1083 British breed beef bulls in 42 herds in Victoria (35) and Western Australia (7) by means of the serving capacity test. The herd prevalence was 60%. The prevalence of the defect at the initial test for all bulls was 10%. The prevalence in 635 polled bulls was 16% compared to a prevalence of 1 % in 448 horned bulls. The breed prevalence and the number of bulls tested per breed was Red Poll 27% (15), Murray Grey 25% (4), Poll Shorthorn 21 % (34), Angus 17% (415), Poll Hereford 10% (167) and Hereford 1 % (448). The difference between the last 2 breed types was highly significant (P<0.001). The prevalence of the defect increased from 0 to 30% over 9 years in one Victorian herd. The age of affected bulls varied from 2 to 11 years with most affected bulls aged from 3 to 6 years. Common ancestry was found between affected bulls in Western Australia, providing circumstantial evidence that it may be an inherited defect. None of the 103 affected bulls examined in this study had suffered obvious injury to the penis or prepuce. Eighty per cent of 56 affected bulls from Victoria had low serving capacity. Four bulls (2 from each state) with moderate to severe spiral deviation of the penis attained pregnancy rates of 43%, 33%, 3% and 3% respectively, in single sire mating trials. Recommendations for culling defective bulls are presented, based on the herd prevalence and severity of the defect in individual bulls.
It is concluded that bulls with moderate to severe spiral deviation of the penis have reduced fertility and remain permanently affected. The serving capacity test is a valuable diagnostic test for this serving defect in unhandled beef bulls. It is a common, although frequently undiagnosed disorder of polled beef breed bulls in Australia.     

Distribution of Mycobacterium avium subsp. paratuberculosis in organs of naturally infected bull-calves and breeding bulls

Paratuberculosis, caused by Mycobacterium avium subsp. paratuberculosis, has particular importance in cattle due to the resulting chronic diarrhoea, weight loss, decreased production, infertility and eventual death. While faecal oral route of infection is generally recognised, reports about semen-derived infection are rare. The objective of this work was to assess whether M.a. paratuberculosis may disseminate from the gastrointestinal tract to reproductive organs, and compare this event between naturally infected bull-calves and breeding bulls. Ten bull-calves, aged 6-28 weeks and four breeding bulls were tested by serology, faecal and tissue culture, IS900 PCR and RFLP. In seven bull-calves M.a. paratuberculosis was isolated predominantly from mesenteric lymph nodes (75%); isolates from mucosa of the intestine constituted 25%. In three breeding bulls, M.a. paratuberculosis was isolated both from intestinal mucosa and mesenteric lymph nodes. Head and mediastinal lymph nodes, liver, spleen and semen of bull no. 1 (Holstein-Friesian); testes and epididymis of bull no. 2 (Piemonte); testes, epididymides and seminal vesicle of bull No. 3 (Hereford); and seminal vesicle of bull No. 4 (Simmental) tested positive by culture. Hot-start PCR revealed M.a. paratuberculosis in semen, seminal vesicle and intestinal tissue where culture isolation was difficult. Isolates from bull-calves and breeding bulls were of RFLP types B-C9 and B-C1, respectively. Bull-calves born in infected herd can be sources of infection when later used for natural mating or artificial insemination. Sub-clinically infected bulls release M.a. paratuberculosis into semen, consequently infecting the uterine environment of cows.     

Associations between sperm abnormalities, breed, age, and scrotal circumference in beef bulls

The objectives of this study were to determine the associations of breed, age, and scrotal circumference (SC), and their interaction, on the prevalence of sperm abnormalities in beef bulls in Alberta, Canada, and the percentage of satisfactory potential breeders identified during breeding soundness examination solely due to normal sperm morphology. Eosin-nigrosin stained semen smears and evaluation reports of 1642 bull breeding soundness evaluations were procured from 6 veterinary clinics in Alberta. Sperm morphology was determined for at least 100 sperm per bull. The most common defects were detached head [4.86% ± 5.71%; mean ± standard deviation (s)], distal midpiece reflex (6.19% ± 9.13%), and bent tail (1.01% ± 1.54%). Although breed, age, and SC did not significantly affect the prevalence of head or midpiece defects, morphologically normal or abnormal sperm, tail defects were more prevalent in Angus and Hereford bulls compared with other breeds. Overall, solely on the basis of sperm morphology, 1363 (83.0%) bulls were classified as satisfactory potential breeders and the remainder 279 (17.0%) as unsatisfactory (> 30% abnormal sperm, > 20% defective heads, or both). Although not significantly different, the breed with the highest percentage of satisfactory potential breeders was Limousin (90.6%) and the lowest was Hereford (78.8%). That 17% of bulls subjected to breeding soundness evaluation were designated as unsatisfactory solely on the basis of sperm morphology highlights its importance.     

Biosafety and antibody responses of adult bison bulls after vaccination with Brucella abortus strain RB51.

OBJECTIVE: To evaluate clearance, antibody responses, potential shedding, and histologic lesions in reproductive tissues of adult bison bulls after vaccination with Brucella abortus strain RB51. ANIMALS: 61 two- and 3-year-old bison bulls. PROCEDURE: 12 bison bulls were vaccinated s.c. with B abortus strain RB51, 3 were inoculated s.c. with 0.15 M NaCl, and antibody responses were evaluated. Various specimens were obtained to evaluate bacterial shedding. Four vaccinates and 1 control were necropsied 10, 20, and 30 weeks after vaccination. In a separate experiment, bison bulls were vaccinated s.c. with 0.15 M NaCl, or by hand or ballistically with strain RB51. Antibody responses were monitored 6 weeks after vaccination and during necropsy 13 weeks after vaccination. Tissue specimens obtained during necropsy from both studies were evaluated bacteriologically and histologically. RESULTS: Strain RB51 was recovered at various times from semen of 3 of 12 vaccinated bison bulls in experiment 1. During necropsy, strain RB51 was recovered 10 and 20, but not 30, weeks after vaccination. In experiment 2, strain RB51 was recovered from lymphoid tissues of hand- and ballistic-vaccinated bison bulls during necropsy. In both experiments, microscopic lesions in testes, epididymis, and seminal vesicles were minimal and did not differ between strain RB51-vaccinated and saline-inoculated bison bulls. CONCLUSIONS AND CLINICAL RELEVANCE: Strain RB51 does not induce relevant inflammatory lesions in reproductive tissues of adult bison bulls. Shedding of strain RB51 in semen may be transient in some bison bulls; however, the importance of this observation is unknown.     

Foreign substances in the meat and organs of bulls and pigs fed with pastes made from household and food industry waste in addition to pastes made from poultry droppings

The residues of antimicrobial substances, some chlorinated and organophosphate pesticides and chemical elements were studied in the meat and organs of a group of bulls fed food-waste paste for 240 days and a group of bulls fed the same paste with an addition of poultry waste. These residues were also studied in the tissues of pigs fed the food-waste paste for 135 and 151 days until slaughter. The feed ingredients were also examined during the feeding trials. Although some of the residues under study were found in the tissues of the test animals at increased amounts, their concentrations were diluted in the tissues in the majority of cases when the feed pastes were administered. All residue contents recorded in the tissues remained below the permissible limits as given in valid instructions and directives so that the products, i. e. meat and organs, could be deemed digestible on the basis of hygienic evaluation. Hence, from the point of view of the occurrence of residues of foreign substances in edible tissues, the administration of food-waste pastes to farm animals can be considered as admissible.     

Serological evidence of Neospora caninum infections in beef bulls in six counties of the Corrientes province,Argentina

The purpose of the present work was to identify Neospora caninum infections in beef bulls belonging to 19 herds from six counties located in the Corrientes province, Argentina. The presence of antibodies to N. caninum was evaluated in 305 serum samples of bulls (Bos taurus and Bos indicus). Age and breed were recorded. An indirect fluorescent antibody test was used to determine specific antibodies. The number of bulls with natural Neospora-infection was 15 of 305 (4.9%). No association between serologic status and breed (odds ratio (OR), 0.53; 95% CI, 0.18-1.53) was found. Neospora-infected beef bulls were identified in the present work. The bull role in bovine neosporosis and the risk of horizontal transmission for cows should be investigated.     

Breed performance in organic dairy farming in Northern Spain

Organic farm management combines best environmental practices, a high level of biodiversity, preservation of natural resources and high animal welfare standards. To meet these criteria, farmers must have livestock well adapted to local organic conditions and information about how different breeds and crosses perform under different conditions. The objective of this study was to compare the performance of different pure breeds and cross-breeds of cattle in organic dairy systems in Northern Spain. The data analysed were obtained from monthly records kept between 2010 and 2016 on organic farms registered in the regional milk recording system. Analysis of various traits indicated that the Holstein-Friesian breed suits the organic production system in the study region. Although the reproductive performance of Holstein-Friesian cows was poorer (in terms of number of services per conception) than that of cross-breed and Brown Swiss cows, the Holstein-Friesian produced more milk and lived longer. In addition, there was no difference in calving type or calving ease between the different breed groups. The better milk fat and protein yields produced by the crosses may be useful traits for farmers interested in milk transformation. The advantage of continuing to use Holstein-Friesian cattle is that the breed is predominant worldwide, and the genealogy is well documented. If Holstein-Friesian cattle continue to be used, the main priority will be to search for well-adapted bulls (particularly for pasture-based conditions) and to elaborate a genetic merit index for organic and pasture-based systems with the aim of predicting and minimizing genotype × environment interactions.     

补饲微量元素锌对黑白花种公牛冷冻精液品质的影响

对20头日粮中锌含量低于NRC(1978)标准的黑白花种公牛进行补锌试验。补锌3个月显著提高了种公牛冷冻精液的解冻活率,受精能力,但精子的形态和畸形率没有显著的变化。     

Comparison of milk production of the progeny of BLAD-carrier and healthy Holstein bulls in Hungary.

'Bovine Leukocyte Adhesion Deficiency' (BLAD) is a recessive monofactorial, lethal inheritable defect occurring in Holstein-Friesian cattle and often passed on by well-known top bulls. The aim of this study was to find a relationship between the BLAD genotype of bulls, their genetic evaluation for milk and their daughters' milk production. BLAD-carrier and healthy bulls were compared on the basis of their breeding value published in November 1997. The first 100 bulls ranked according to the Total Production Index (TPI) were used, including nine BLAD carriers with 2,835 daughters and 77 healthy sires with 21,950 female progenies. For 14 bulls the BLAD genotype was not indicated. The healthy animals significantly outperformed the BLAD carriers, which result contradicts our earlier findings (Dohy et al., 1996; Jánosa and Dohy, 1997). In a BLAD elimination programme, the identification of BLAD carriers and properly planned mating are of great importance in order to avoid 'inter se' mating of BLAD-carrier top animals which can be of significant influence in Holstein breeding.     

Growth and pubertal development in Brahman-, Boran-, Tuli-, Belgian Blue-, Hereford- and Angus-sired F1 bulls

Growth and testicular development between 7 and 15 mo of age were evaluated in bulls produced by mating sires of six breeds (Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli) to Angus, Hereford, and MARC III (four-breed composite) cows. At 12 mo of age, Angus- and Hereford-sired bulls had the heaviest body weight (P < 0.08 to 0.001), whereas Brahman- and Belgian Blue-sired bulls were intermediate, and Boran- and Tuli-sired bulls weighed the least. Bulls sired by European breeds grew more rapidly after weaning (P < 0.01) than did Brahman-, Boran-, and Tuli-sired bulls, and these differences in growth rate were maintained through 15 mo of age, indicating that offspring of heat-adapted sire breeds (Brahman, Boran, and Tuli) have lower postweaning rates of gain, particularly during winter months, than do offspring of nonheat adapted sire breeds. Testis size was smaller initially (P < 0.01) and remained smaller in offspring of heat-adapted sire breeds through yearling age. By 15 mo of age, testis size was largest (P < 0.06 to 0.001) in Angus-sired bulls and had become similar among Hereford-, Brahman-, Boran- and Belgian Blue-sired bulls but remained smaller (P < 0.02 to 0.001) in Tuli-sired bulls. Thus, offspring of heat-adapted sire breeds had delayed testicular development compared with that of nonheat adapted sire breeds, particularly through yearling age. At puberty, Angus-sired bulls were 23 to 82 d younger (P < 0.05 to 0.001) than all other sire breeds except Hereford, and Brahman-sired bulls were older at puberty (P < 0.05 to 0.001) than were bulls of all other sire breeds except Boran. Testis size at puberty was quite similar among breeds of bulls (scrotal circumference = 27.9 +/- 0.1 cm) despite large breed differences in age, body weight, and hip height. Thus, measurement of yearling testis size was a reliable indicator of age at puberty among widely divergent breeds of bulls. In addition, the lower postweaning rates of gain and the smaller and slower testicular development in offspring of heat-adapted sire breeds should be noted by cattle producers considering use of such breeds in crossbreeding and breed improvement programs.     

Exploratory analysis of differences in sperm morphology in Nelore and Gir (Bos indicus) bulls

The aim of this study was to evaluate the effects of breed and season on semen quality parameters of zebu bulls. Data (1,632 registers) of semen production from Gir (n?=?4) and Nelore (n?=?15) bulls were collected between October 2005 and November 2009. The ejaculates were collected twice a week during various seasons (summer, fall, winter, and spring) and evaluated for the following semen parameters: ejaculate volume, sperm concentration, sperm motility, forward progressive motility (FPM), and sperm morphology. Factor analysis was used to determine the relationship among variables. The effect of breed (Gir and Nelore) and season and their cross effect on each parameter and extracted factor were tested using ANOVA. A negative correlation (P?<?0.05) was observed between FPM and proximal droplet, as well as with abnormal loose head, abnormal small head, pouch formation, abnormal mid-peace, and strongly folded tail. Gir bull sperm showed more major defects, detached acrosome, and minor FPM (P?<?0.01), whereas Nelore bulls showed a higher number of sperm with normally loose head.     

Evaluations of genotypexenvironment interactions of beef bulls performance-tested in feedlot or pasture

Purebred Angus (n = 96) and Polled Hereford (n = 96) bull calves sired by bulls of either low or high yearling weight performance lines were assigned to either creep-fed or non-creep-fed treatment before weaning for four calf crops. For each breed, after weaning in the fall, half of the calves within each of the four groups were fed a high concentrate diet for 189 d after weaning in a feedlot and the remainder were put on winter temporary pastures (rye or ryegrass) followed by summer grazing on pearl millet and bermudagrass pastures for 329 d after weaning. Dependent variables were ADG for various intervals and the complete test period, weight, height and scrotal circumference at periodic intervals, and weight per day of age at regular intervals during the test. The model included breed, performance line, sire nested within breed and line, year, age of dam, preweaning treatment, postweaning treatment, and two- and three-factor interactions. Age of calf was included as a covariate for weight, height, and scrotal circumference measurements. Line and breed differences generally were significant for weight but not for height. The interaction of primary interest (line by preweaning treatment by postweaning treatment) was not significant. The high growth performance line gained faster than low growth performance line for all intervals and were 45 kg heavier by 189 d after weaning. Preweaning treatment did not affect postweaning ADG but did affect weight per day of age. Creep-fed calves were heavier than non-creep-fed calves and maintained this advantage during the postweaning treatment periods in both the feedlot and pasture. Both preweaning treatment groups had similar ADG after weaning. Angus were 23 kg heavier at weaning than Polled Herefords; however, breed weight means were similar by 16 mo of age. In summary, bulls from different selection lines for growth were identified in feedlot and pasture when adjustments were made for prior management effects. The lack of significant interactions in these data indicates that central test station data, appropriately adjusted, are useful for ranking bulls on genetic merit for growth in feedlot and on pasture.     

Relationships between breeding values and physiological responses to fasting and refeeding in dairy bulls: update for young animals

SUMMARY: Relationships between plasma concentrations of growth hormone (GH), free fatty acids (FFA), urea (UR), glucose (GL) and insulin (IN) and estimated breeding values (EBV) were examined for 213 Australian Holstein-Friesian diary bulls tested in 1985-1988 at four artificial breeding centres. Measurements were taken before and after 3 days of fasting and, for 124 bulls sampled in 1987 or later, 24 h after resumption of feeding. Results for 150 older bulls at two centres (V and N) are compared with those for 27 bulls averaging 27 months tested at centre N and of 37 yearling bulls tested at two other centres. Both younger and older bulls showed low positive correlations of around 0.25 between mean plasma GH and EBVs. However, earlier results from centre V suggesting relationships between EBVs and the increase in FFA with fasting, the subsequent decrease in FFA and increase in GL following resumption of feeding were not repeated for the younger bulls which exhibited substantially higher concentrations of FFA and lower concentrations of insulin after 3 days of fasting. ZUSAMMENFASSUNG: Zusammenh?nge zwischen Zuchtwerten und physiologischen Reaktionen auf Hungerperioden und Wiederaufnabme der Fütterung bei Milchviehbullen-aktualisierte Untersuchung fur jüngeren Bullen Die Zusammenh?nge zwischen Plasmakonzentrationen von freien Fetts?uren (FFA), Harnstoff (UR), Glukose (GL), Insulin (IN) und Somatrotopin (GH) und Zuchtwerten (ZW) 213 australischer Holstein-Friesian Bullen wurden untersucht. Die physiologischen Messungen wurden im Zeitraum 1985-1988 in vier KB Stationen vor und nach einer 3-t?gigen Hungerperiode durchgeführt. Für 124 Bullen, die nach 1986 geprüft wurden, wurden zus?zliche physiologische Messungen 24 Stunden nach der ersten Futteraufnahme durchgeführt. Die Ergebnisse von 150 ?lteren Bullen von 2 Stationen (V und N) wurden verglichen mit den Ergebnissen von 27 jüngeren Bullen mit einem Durchschnittsalter von 27 Monaten, die in der Station N geprüft wurden und weiterhin mit den Ergebnissen von 37 Bullen, die in zwei weiteren Stationen getestet wurden. Sowohl für die jüngeren als auch für die ?lteren Bullen wurden geringe positive Korrelationen von ungef?hr 0,25 zwischen dem durchschnittlichen Somatropin Gehalt und dem ZW festgestellt. Frühere Ergebnisse der Station V zeigten Beziehungen zwischen dem ZW der Bullen und einem Anstieg der FFA w?hrend der Hungerperiode mit einem anschlie?endem Absinken der FFA und einem gleichzeitigem Ansteigen des Glucosegehaltes nach der erste Futteraufnahme. Diese Beziehungen zwischen den ZW und den Gehalten an FFA und GL wurden für die jüngeren Bullen nicht beobachtet, die h?herere Konzentrationen von FFA und geringere Konzentrationen von IN nach einer 3-t?gigen Hungerperiode zeigten.     

Comparison of Computer-assisted Sperm Motility Analysis Parameters in Semen from Belgian Blue and Holstein–Friesian Bulls

Subjective microscopic sperm motility results have recently been demonstrated to differ between Holstein-Friesian (HF) and Belgian Blue (BB) bulls. However, such assessments are rather imprecise. In the present study, sperm motility was assessed objectively by means of the Hamilton Thorne CEROS version 12.2c computer-assisted sperm motility analyser (CASA), and differences between the BB and HF breed could also be demonstrated. Higher percentages of both totally (p < 0.0001) and progressively (p < 0.0001) motile spermatozoa were encountered in the HF breed compared with the BB breed. Furthermore, a lower kinetic efficiency of the BB spermatozoa, evidenced by a lower beat cross-frequency (p = 0.0007) combined with a higher lateral head displacement (p = 0.0015), was the basis for the lower velocity of BB sperm cells. Additionally, BB spermatozoa move less straight forward, resulting in a lower straightness (p < 0.0001). No sperm motility differences were observed between age groups within the BB breed. The breed differences were observed in the examined bull populations residing at AI centres, in Belgium for the BB bulls and in the Netherlands for the HF bulls. However, these bull populations are selected for fertility. A similar pattern was observed in an unselected bull population of both breeds, although these differences were mostly non-significant for the different CASA parameters. Nevertheless, these data suggest that a genetic component might be responsible for the observed sperm motility breed differences.     

Evaluation of reproductive performance and genetic variation in bulls of the Polish White‐Backed breed

The aim of the study was to evaluate genetic variation, reproductive performance and the degree of relationship of White‐Backed bulls entered in the breed registry and approved for breeding. The study included 32 bulls of the White‐Backed (WB ) breed with an entry in the breed registry and used for breeding in the years 2003–2015. Eleven microsatellite DNA sequences (TGLA 222, BM 2113, TGLA 53, ETH 10, SPS 115, TGLA 126, TGLA 122, INRA 23, ETH 3, ETH 225 and BM 1824) were used to analyse variation in the WB bulls. The bulls most often used for breeding were Chilon (1,073 doses), Mak (939 doses) and Jaguar (858 doses). The bulls Mak, Chilon and Jak had the greatest influence on the active population of White‐Backed cattle, with the most daughters. In the analysed population of White‐Backed bulls, a total of 79 different alleles were identified, with a mean 7.27 per locus. The analysed pool of microsatellite loci was characterized by high values for PIC , H _O and H _E (>0.6), and the entire population was in genetic equilibrium. The estimated level of inbreeding within the population ranged from ?0.2277 (ETH 225) to 0.0775 (SPS 115), with a mean value of ?0.0587.     

Growth, puberty, and carcass characteristics of Brahman-, Senepol-, and Tuli-sired F1 Angus bulls

Postweaning growth, sexual development, libido, and carcass data were collected from two consecutive calf crops using 31 Brahman x Angus (B x A), 41 Senepol x Angus (S x A), and 38 Tuli x Angus (T x A) F1 bulls. Following weaning (by mid-September) and preconditioning, at the start of the study (late September) bulls were fed concentrate (three times each week at a rate equivalent to 4.5 kg/d) on bahiagrass pasture for approximately 250 d. At the start of the study and at 28-d intervals, BW, hip height, and scrotal circumference (SC) were measured. Concurrently at 28-d intervals, when the SC of a bull was > or = 23 cm, semen collection was attempted using electroejaculation. Ejaculates were evaluated for presence of first spermatozoa (FS), 50 x 10(6) sperm with at least 10% motility (PU), and 500 x 10(6) sperm with at least 50% motility (PP). After all bulls reached PP they were subjected to two libido tests. Carcass data were collected on all bulls (n = 110) and Warner-Bratzler shear (WBS) force values were assessed on a subset (n = 80). For both years, B x A bulls were heavier (P < 0.05) and taller (P < 0.05) than S x A and T x A bulls at the start and end of the study. However, breed type did not influence (P > 0.10) gain in BW or hip height during the study. Scrotal circumference of T x A bulls was larger (P < 0.05) than that of B x A or S x A bulls at the start of the study, but there was no effect (P > 0.10) of breed type by the end of the study. At PU and PP, B x A bulls were older (P < 0.05), heavier (P < 0.05), and taller (P < 0.05) and had larger (P < 0.05) SC than S x A and T x A bulls. Tuli x Angus bulls were younger (P < 0.05) than S x A bulls at PU and PP but had similar SC. Libido scores tended (P < 0.10) to be lower for B x A than for S x A and T x A bulls. Breed type affected (P < 0.05) carcass traits; B x A bulls had the heaviest (P < 0.05) hot carcass weight, greatest (P < 0.05) dressing percentage, larger (P < 0.05) longissimus muscle area than S x A bulls, and higher (P < 0.05) USDA yield grade than T x A bulls but greatest (P < 0.05) WBS force values. Breed type did not affect (P > 0.10) USDA quality grade. In conclusion, tropically adapted F1 bulls produced from Senepol (Bos taurus) and Tuli (Sanga) sires bred to Angus cows in Florida had lighter BW, shorter hip heights, and smaller carcasses than those from Brahman sires but reached puberty earlier and had higher libido scores and lower WBS force values.     

Foreign substances in the meat and organs of bulls fed on a diet of swine and poultry fecal waste

The meat and some organs of eight bulls given diet with 5% to 15% supplements of dried pig and poultry excrements for 175 days were subjected to examination for the presence of some foreign substances. The results were compared with samples from eight control bulls, fed the basal diet. Liver was not found to contain any aflatoxins B1 and M1. No statistically significant differences were found in the content of antimicrobial substances. The same can be said of the content of chlorinated pesticides. Residues of organo-phosphorus pesticides were not detected at all. As to chemical elements, the test bulls were found to have a significantly increased content of copper in liver and diaphragm. All the findings of the residues of foreign substances were within limits tolerated by veterinary regulations.