Seminal Leucocytary Profile in Beef Bulls

Despite evidences that seminal leucocytes could affect semen quality, references for the frequency and concentration of these cells in bulls are not available. The aim of this study was to determine the normal concentration of leucocytes in beef bulls and to correlate this characteristic with semen quality. First, 57 bulls from artificial insemination centres were evaluated to obtain the normal leucocytary profile values. Next, 382 bulls were subjected to breeding soundness evaluation. The average concentration of leucocytes in bovine semen was 4.73 × 10⁶/ml. Unsatisfactory bulls showed a higher number of leucocytes/field than that in the satisfactory ones. Logistic regression analysis revealed that the unsatisfactory bulls showed 6.5‐fold more chances of having higher leucocyte counts than satisfactory ones. Values of up to 1 leucocyte/field in the bull ejaculate are considered physiologically normal, whereas >5 leucocytes/field is associated with poor semen quality.     

Associations between lamb growth to weaning and dam udder and teat scores

ABSTRACT

Aims: To investigate associations between lamb growth to weaning and dam udder and teat scores measured at pre-mating, pre-lambing, docking and weaning.

Methods: Mature Romney ewes (n?=?1,009) were enrolled from a commercial sheep flock located near Masterton, in the Wellington region of New Zealand in 2017. A range of udder and teat traits were scored in all ewes, using visual assessment and palpation, at pre-mating, pre-lambing, docking and weaning. During the lambing period, each newborn lamb was matched to its dam and lamb sex, birthweight and birth-rank were recorded. A rearing rank was allocated to each live-lamb at weaning, when all lambs were weighed (n?=?1,570), allowing calculation of daily growth rates (g/day). Associations between udder and teat scores and lamb growth rates to weaning were examined using multivariable models for each udder-scoring time.

Results: Growth rates of lambs whose dams had udder palpation scores of hard, or both teats recorded as abnormal, pre-mating were lower than lambs whose dams had normal scores (229.9 (95% CI?=?213.2–246.6) vs. 254.5 (95% CI?=?245.6–263.5) g/day; p?=?0.011) and (227.4 (95% CI?=?208.3–246.6) vs. 247.9 (95% CI?=?235.7–260.2) g/day; p?=?0.024), respectively. Growth rates of lambs whose dams had clinical mastitis at docking or weaning were lower than those without mastitis (215.8 (95% CI?=?199.9–231.7) vs. 235.4 (95% CI?=?225.4–255.0) g/day; p?=?0.007) and (220.0 (95% CI?=?205.2–234.8) vs. 254.7 (95% CI?=?248.9–260.5) g/day; p?<?0.001), respectively. Growth rates of lambs whose dams had asymmetrical udders at docking or weaning were lower than lambs whose dams had symmetrical udders (204.6 (95% CI?=?189.7–219.5) vs. 240.2 (95% CI?=?225.4–255.0) g/day; p?<?0.001) and (223.3 (95% CI?=?213.9–232.7) vs. 242.2 (95% CI?=?229.4–255.0) g/day; p?=?0.014), respectively.

Conclusions and Clinical Relevance: Pre-mating udder palpation and teat palpation scores can be used to identify ewes whose lambs are predicted to have lower growth to weaning. Assuming a mean lamb age at weaning of 84.4 days, lambs born to ewes with a pre-mating score of hard would be expected to have a mean weaning weight that was 2.1?kg less than those whose dams had normal scores. Udder palpation, udder symmetry and clinical mastitis scores during lactation were also associated with lamb growth rates.

Abbreviation: CALW: Conceptus-adjusted liveweight     

Attitudes and practices of Queensland dairy farmers to the control of the cattle tick, Boophilus microplus

Objective To determine practices for the control of cattle ticks on dairy farms in Queensland, the attitudes of farmers to tick infestations and to identify opportunities for and barriers against the introduction of non-chemical methods of tick control.
Design A survey of 199 dairy farmers from tick-infested parts of Queensland was undertaken by 20 dairy advisers and stock inspectors from October 1996 to June 1997. The sample was a proportional, random selection of dairy farms from four regions. A personal interview was conducted with each farmer and answers to 134 questions were obtained.
Results and conclusions Most farmers were not concerned by cattle ticks on their own farms, although they believed that ticks are important to the dairy industry. They were most concerned about the development of chemical resistance by cattle ticks. Inadequate facilities and lack of motivation appeared to be the factors most limiting to improving the methods of control. Most farmers claimed to have only small numbers of ticks at worst. Although a control program recom mended by the Queensland Dairyfarmers' Organisation was well regarded by farmers, few had adopted it. Many farmers saw no need to implement a strategic control program.     

Effect of synchronization protocols on reproductive indices,progesterone profile and fertility under subtropical environmental conditions in repeat breeder Holstein cows

The objectives were to evaluate the reproductive indices and survival analysis of pregnancy outcomes in multiparous repeat breeder Holstein cows (n = 557). The cows were synchronized to ovulate by Ovsynch, new controlled internal drug release device (N‐CIDRsynch), and once‐used CIDR device (U‐CIDRsynch). The pregnancy per AI at 28 days post‐insemination (P/AI 28) in the N‐CIDRsynch group (28.75%) was significantly (COR = 1.49; p = 0.011) greater than that reported in the Ovsynch (23.46%) and U‐CIDRsynch (21.73%) groups. Furthermore, the pregnancy per AI at day 75 post‐insemination (P/AI 75) in the N‐CIDRsynch group was significantly greater than the Ovysync group (COR = 1.35; p = 0.050). The repeat breeder cows received a N‐CIDR device had a significantly higher progesterone level on day 2 and day 4 of CIDR insertion (1.38 and 1.67 ng/ml, respectively) than those received a U‐CIDR device or the control group (p = 0.012 and 0.001, respectively). The Cox regression model recorded significant associations for synchronization protocols, THI at the TAI and season of calving with the hazard of P/AI 28 and P/AI 75 (p = 0.044 and 0.046; 0.001 and 0.005; 0.003 and 0.001, respectively). Multiparous repeat breeder cows (>3) had a lower hazard ratio (HR) of P/AI 28 than that reported in the reference (2nd parity) group (HR = 0.74, p = 0.050). The repeat breeder cows inseminated at 76–80 and >80 temperature‐humidity index (THI) had significantly lower HR of P/AI 28 than those inseminated at the baseline (<70) THI value (HR = 0.73 and 0.30, p = 0.036 and 0.001, respectively). The current results indicate that the use of N‐CIDR synch protocol may achieve satisfactory pregnancy outcomes in repeat breeder cows.     

Familial episodic ataxia in lambs

Abstract

HISTORY: A similar episodic neurological disorder occurred in new born lambs on two unrelated properties involving disparate breeds of sheep. Because of the number of lambs born, cross-breeding and the fact it occurred in some mating groups and not others, a dominant mode of inheritance was, initially and separately, suspected in each case. The sires of affected lambs were apparently normal. Whereas one was New Zealand Romney, the other was a composite breed with East Friesian genetics, but both rams originated from the same source property. To investigate the pathogenesis of the disorder these two rams were acquired and mated with unrelated sheep, under experimental conditions in a more controlled environment.

CLINICAL FINDINGS: A proportion of lambs born to both sires exhibited a similar neurological disorder. Some lambs were noted to be abnormal at birth, both on home properties and in the experimental flock. They tended to adopt a head and neck extended posture and were slow to get to their feet and suckle when they then became more or less normal. When forced to move, they and other more robust lambs elicited an asymmetric gait, base-wide extensor hypertonia (hypometria) of thoracic limbs and flexor hypertonia (hypermetria) of pelvic limbs. In some there was nystagmus. After several metres of asymmetric ataxic gait they would fall to one side, sometimes adopting a sitting position. Recovery usually occurred in one to several minutes. As lambs aged, it became more difficult to elicit the episodes of dysfunction and by 6 months of age they appeared normal.

DIAGNOSIS: The disorder was diagnosed as a dominant familial episodic cerebellovestibular ataxia inherited as a dominant trait, with incomplete penetration of observed clinical signs and variable expressivity.

CLINICAL RELEVANCE: A proportion of affected lambs are likely to die in the neonatal period so the specific nature of the disorder may go unrecognised. Because of incomplete penetrance and varying expressivity, many of the lambs carrying this mutation will survive without showing clinical signs and may enter breeding flocks, where the disorder may be perpetuated and contribute to neonatal deaths.     

Effectiveness of small workshops for improving farmers knowledge about ovine footrot

OBJECTIVE: To determine sheep farmers' attitudes to and beliefs about ovine footrot, and to improve their knowledge about the diagnosis, control and eradication of this disease. METHOD: Eighteen workshops, involving 291 farmers, were conducted across Victoria in the spring of 1996. The workshops were designed as small-group discussions with a maximum attendance of 20 farmers to encourage active participation. All participants completed questionnaires before each workshop and 12 to 40 weeks after the last workshop. RESULTS: Before the workshops the farmers had a poor understanding of the principles of diagnosis, control and eradication of footrot. For example, only 50% knew the footrot organism survived in soil for less than 7 days, over two-thirds did not know the reason for paring sheep's feet during an eradication program, and only 31% realised cattle were a potential source of footrot infection for sheep. After the workshops, understanding about footrot was significantly improved; 87% said Dichelobacter nodosus survived in soil less than 7 days, 71% knew the reason for paring sheep's feet and 64% realised that cattle were a potential source of footrot infection. As well as improved knowledge, change of attitude among farmers is fundamentally important if virulent footrot is to be successfully controlled and eradicated. The workshops successfully initiated this process; 40% of farmers thought the workshops changed their attitudes to footrot, while 37% said they gained an increased understanding of other people's opinions about the disease. CONCLUSION: Farmers' poor understanding of ovine footrot is a constraint to the programs aimed at controlling this disease. Small group workshops may be an effective way to influence farmers' attitudes and beliefs, and could facilitate the effectiveness of regulatory disease control programs.     

Assessment of Sperm DNA Fragmentation in Stallion (Equus caballus) and Donkey (Equus asinus) Using the Sperm Chromatin Dispersion Test

Sperm DNA fragmentation (sDF) is an important parameter to assessing sperm quality. Information about sperm quality is not available for donkeys, especially in some breeds at risk of extinction. The objectives of this research were to test the four commercial variants of sperm chromatin dispersion test (SCD; sperm Halomax test), originally developed to assess sDF in boars, bulls, rams and stallions, in order to scrutinize their applicability in the study of sDF in a donkey breed at risk of extinction (Zamorano-Leonesa), for which there is no specific test available to analyze sperm at present. Only the SCD test, originally developed for stallions, produced stable and consistent results, and was deemed suitable to assess DNA fragmentation in sperm samples from donkeys. Image analysis was used to compare differences between the SCD methodology applied to stallion and donkey semen samples processed under the same experimental conditions. The extent of SCD in the SCD test was approximately 20% lower in donkey sperm than in stallion sperm. Yet, the ratio of chromatin sperm dispersion achieved in fragmented and unfragmented nuclei did not differ significantly between species. These data suggest that a similar protein depletion treatment can cause differences in protein removal in equivalent cells from different species and that sperm chromatin may be organized differently in stallions and donkeys.     

Effects of transportation during the hot season,breed and electrical stimulation on histochemical and meat quality characteristics of goat longissimus muscle

The effects of transportation and electrical stimulation (90 V) on physiological, histochemical and meat quality characteristics of two breeds of Omani goats were assessed. Twenty 1‐year‐old male goats from each breed (Batina and Dhofari) were divided into two groups: 3 h transported during the hot season (42°C day time temperature) and non‐transported. Animals were blood‐sampled before loading and prior to slaughter. Electrical stimulation was applied 20 min postmortem to 50% randomly selected carcasses of both breeds. Temperature and pH decline of the Longissimus was monitored. Ultimate pH, shear force, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and colour were measured from samples of Longissimus dorsi muscles. Electrical stimulation and transportation had a significant effect on most biochemical and meat quality characteristics of Longissimus dorsi. The transported goats had higher plasma cortisol (P < 0.01), adrenaline, nor‐adrenaline and dopamine concentrations (P < 0.05) than non‐transported goats. Electrical stimulation resulted in a significantly (P < 0.05) more rapid muscle pH fall during the first 12 h after slaughter. Muscles from electrically‐stimulated carcasses had significantly (P < 0.05) longer sarcomeres, lower shear force value, a lighter colour (higher L* value), higher expressed juice and myofibrillar fragmentation index than those from non‐stimulated ones. Meat from transported goats had significantly higher pH, expressed juice and shear force, but contained significantly lower sarcomere length and L* values than non‐transported goats. The proportion of the myosin ATPase staining did not change as a function of stimulation, transportation or breed. These results indicated that subjecting goats to transportation for 3 h under high ambient temperatures can generate major physiological and muscle metabolism responses. Electrical stimulation improved quality characteristics of meat from both groups. This indicates that electrical stimulation may reduce detrimental effects of transportation on meat quality of Omani goats.