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1.
The pharmacokinetic profile of avermectin and milbemycin compounds is affected by different drug- and host-related factors. This work reports the influence of cattle breeds on the plasma kinetics of moxidectin (MXD) after topical (pour-on) administration. Parasite-free Aberdeen Angus and Holstein calves were treated with a commercial MXD pour-on formulation at 500 microg/kg. Blood samples were collected over a period of 35 days post-treatment and the recovered plasma was analysed by high performance liquid chromatography using fluorescence detection. MXD was detected in plasma from two hours up to 35 days post-treatment in animals from both breeds. A slow MXD absorption and delayed peak plasma concentration were observed in Aberdeen Angus compared to Holstein calves. Significant lower systemic availability (expressed as AUC) (P<0.01) and peak plasma concentration (C(max)) (P<0.05) were also observed in Aberdeen Angus calves, although the plasma mean residence time (MRT) and elimination half-lives (T(1/2el)) of MXD in both breeds were similar. The pharmacokinetic differences observed between cattle breeds contribute to explain the variability in the pattern of clinical efficacy for pour-on administered endectocide compounds reported in different field trials.  相似文献   

2.
An oil emulsion Escherichia coli bacterin administered in 1- and 2-dose vaccination regimens was evaluated in beef cattle. Serologic responses to the K99 pilus antigen were monitored, and suckling offspring from vaccinated and nonvaccinated cows were inoculated with virulent, K99-positive, enterotoxigenic Escherichia coli. The degree of protection and duration of immunity conferred were determined in 2 respective studies. In the first study (study A), titers of pregnant cattle were determined from time of vaccination through calving (a 6- to 20-week period). Titers of 24 cows vaccinated with a single 2-ml dose of bacterin were compared with those of 24 cows given a 2-dose regimen and with those of 23 nonvaccinated cattle (contemporary controls). Inoculum consisting of 1.2 X 10(12) viable enterotoxigenic E coli/dose administered to nursing calves from these dams yielded 0% mortality (0 deaths/20 calves) in calves from 1-dose vaccinates, 6% mortality (1 death/18 calves) in calves from 2-dose vaccinates, and 37% mortality (7 deaths/19 calves) in calves from nonvaccinated dams. Study B was an extended evaluation conducted in cattle that were kept in the study up to 87 weeks from initial vaccination until calving. Serologic titers to the K99 pilus antigen were compared in 1-dose, 2-dose, and nonvaccinated cattle in groups of 8, 6, and 6, respectively. Calves from these dams were inoculated with 8.1 X 10(11) viable enterotoxigenic E coli/dose, which resulted in 0% mortality (0 deaths/5 calves) in calves from 1-dose vaccinates, 0% mortality (0 deaths/5 calves) in calves from 2-dose vaccinates, and 80% mortality (5 deaths/6 calves) in calves from nonvaccinated dams.  相似文献   

3.
Abstract

Due to the competition with high yielding international dairy breeds, many local cattle breeds that traditionally supplied the European dairy market are being marginalised and thus increasingly endangered. While there are many options to enhance profitability of dairy utilisation of local dual purpose cattle breeds, in some of them, for various reasons, milk utilisation is continuously declining and dairy herds are gradually transformed into less labour demanding suckling herds. However, sometimes there is no consensus among breeders and breeding organisations on dividing dual-purpose breeds into dairy and beef subpopulations. The paper examines the pros and cons of this approach using case studies from Poland, Norway and Austria. While there are disadvantages in turning a breed traditionally milked to beef production, sometimes it is the only valid option to continue its utilisation. Therefore, trade-offs need to be considered and conservation steps taken before starting the transformation of a breed.  相似文献   

4.
The objective of this study was to characterize breeds representing diverse biological types for birth and weaning traits in crossbred cattle. Gestation length, calving difficulty, percentage of unassisted calving, percentage of perinatal survival, percentage of survival from birth to weaning, birth weight, BW at 200 d, and ADG were measured in 2,500 calves born and 2,395 calves weaned. Calves were obtained by mating Hereford, Angus, and MARC III (one-fourth Hereford, one-fourth Angus, one-fourth Pinzgauer, and one-fourth Red Poll) mature cows to Hereford or Angus (British breed), Brahman, Tuli, Boran, and Belgian Blue sires. Calves were born during the spring seasons of 1992, 1993, and 1994. Sire breed was significant for all traits (P < 0.002). Offspring from British breeds and the Belgian Blue breed had the shortest gestation length (285 d) when compared with progeny from other sire breeds (average of 291 d). Calving difficulty was greater in offspring from Brahman sires (1.24), whereas the offspring of Tuli sires had the least amount of calving difficulty (1.00). Offspring from all sire breeds had similar perinatal survival and survival from birth to weaning (average of 97.2 and 96.2%, respectively), with the exception of offspring from Brahman sires, which had less (92.8 and 90.4%, respectively). Progeny of Brahman sires were heaviest at birth (45.7 kg), followed by offspring from British breed, Boran, and Belgian Blue sires (average of 42.4 kg). The lightest offspring at birth were from Tuli sires (38.6 kg). Progeny derived from Brahman sires were the heaviest at 200 d (246 kg), and they grew faster (1.00 kg/d) than offspring from any other group. The progeny of British breeds and the Belgian Blue breed had an intermediate BW at 200 d (238 kg) and an intermediate ADG (average of 0.98 kg/d). The progeny of Boran and Tuli sires were the lightest at 200 d (227 kg) and had the least ADG (0.93 kg/d). Male calves had a longer gestation length, had a greater incidence of calving difficulty, had greater mortality to weaning, were heavier, and grew faster than female calves. Sire breed effects can be optimized by selection and use of appropriate crossbreeding systems.  相似文献   

5.
The objective of this study was to characterize genetic and environmental factors influencing bovine respiratory disease (BRD) in beef cattle. Records from nine purebred and three composite breeds and a variety of F1 and three-way crosses, including the progeny of 12 additional different sire breeds produced over a 20-yr period (1983 to 2002), were evaluated for breed and heterozygosity effects on the observed incidence of BRD. Heterozygosity fractions for calves and dams were defined by generalized breed origins: British, Continental, and tropically adapted. Variance components were estimated for each pure and composite breed, and across all breeds and crossbreeds. The effect of incidence of observed BRD was determined by comparing groups of low and high years of incidence. Respiratory disease in this herd followed a standard epidemiological pattern of initial introduction, reaching an epidemic stage at 70 to 170 d of age, followed by a period of rapid decrease to weaning. Estimates of heritability of incidence of BRD were low, ranging from 0.00 to 0.26, with overall estimates of 0.07 and 0.19 depending on the data set analyzed. The highest incidence of BRD in preweaned calves occurred in the Braunvieh breed (18.8%). The genetic correlation between the direct and maternal genetic effects was generally large and negative, suggesting dams genetically superior for resisting BRD raise calves that are more susceptible. Perhaps maternally superior dams provide passive immunity to their calves, which delays the development of the calves' direct immune system, making them more prone to BRD during the preweaning period. Heterozygosity of calves decreased the incidence of BRD compared with purebred cattle. Calves that were Continental x British or tropically adapted x British breeds had a lower incidence of BRD than did calves of British x British breeds. As the annual incidence of BRD increased, there was an associated increase in the heritability estimate. The estimated heritability based on an underlying continuous scale was large (h2 = 0.48), inferring response to selection for BRD resistance could be large if the phenotype for BRD resistance was known.  相似文献   

6.
A form of congenital hypotrichosis, commonly know as the "rat-tail syndrome," occurs in a small percentage of calves produced by crossing some Continental cattle breeds with cattle that are black in color. These calves are characterized by short, curly, malformed, sometimes sparse hair and a lack of normal tail switch development. In our first study, performance of 43 rat-tail calves was compared with that of 570 non-rat-tail calves of the same breeding and contemporary groups. All rat-tail calves were sired by Simmental bulls and were from cows with various percentages of Angus breeding. The rat-tail condition had no effect on birth weight, weaning weight, or gain from birth to weaning. However, rat-tail calves had significantly lower rates of gain during the winter months from weaning to yearling than non-rat-tail calves, resulting in a 19 kg lighter yearling weight. Gains of steers from yearling to slaughter were not significantly different, but rat-tail steers were 36 kg lighter (P = .01) and 13 d older (P = .15) at slaughter than the non-rat-tail steers. In a second study, Angus-Simmental F1 males and females with the rat-tail condition were mated to produce 64 F2 offspring that were used to determine the mode of inheritance of this syndrome. Analysis showed that the rat-tail syndrome is controlled by interacting genes at two loci. Cattle that express the syndrome must have at least one dominant gene for black color and be heterozygous at the other locus involved.  相似文献   

7.
Plasma leptin concentrations depend on energy intake and fat stores and are modified by hormones, such as glucocorticoids. We have measured plasma leptin concentrations in pre-term calves (born on day 277 of gestation) during the first week of life, in full-term calves (290 days of gestation), fed similar amounts of nutrients with colostrum or a milk-derived formula, combined with or without dexamethasone treatment (to simulate a high glucocorticoid status), during the first five days of life, and in calves fed with an automatic feeder or by bucket or suckling on dams up to day 28. Leptin concentrations increased (P<0.05) from birth to day 7 in pre-term calves. In full-term calves leptin concentrations were stable from day 1 to day 4 in colostrum-fed animals, but decreased (P<0.05) and were lower (P<0.05) if fed a formula with similar amounts of energy and macronutrients as colostrum. Concentrations increased (P<0.05) from day 1 to day 2 in calves suckling on dams and then remained elevated, but did not change and were lower in calves fed with the automatic feeder or by bucket than in suckling calves. Dexamethasone only slightly elevated leptin concentrations. There was no episodic secretion pattern, and there were no consistent associations of leptin with various metabolites and hormones. In conclusion, plasma leptin in young calves with respect to effects of nutrition (low energy intake) and hormones (glucocorticoids) and in association with metabolic changes behaved differently from what is known in mature cattle.  相似文献   

8.
We present epidemiological data from Bavaria that indicates that animals of the Brown Swiss (BS) cattle breed might be more susceptible to BSE than animals from other breeds, both in terms of disease prevalence and length of the incubation period. BS animals were disproportionately represented among the BSE cases (BS represented about 9% of the susceptible population but 27% of actual cases). BS were slaughtered at a higher age (5.8 years vs. 5.0 years for other breeds), and there is a higher prevalence of feeding proprietary feeds to BS calves than calves from other breeds. There was no difference in the recorded feeding practice of BSE-positive animals from BS or other breeds. These results would lead to expect a higher prevalence of BSE in the BS population, with BS BSE animals being of equal age or older than BSE animals from other breeds. In contrast, median age at BSE detection was significantly lower in BS animals than in other breeds (61.4 vs. 68.8 months). There was no difference in the identification categories of BSE between BS animals and animals of other breeds that could explain this difference in age. BS cattle are reported to have more octapeptid repeats in the prion protein gene than other breeds, which could account for shorter incubation periods and higher susceptibility. These observations suggest that BS animals and their tissues should be used in further studies into genetic determinants of BSE susceptibility in cattle.  相似文献   

9.
A bilateral hip lameness has been found in young beef bulls of the Hereford, Aberdeen Angus, Galloway and Charolais breeds in the United Kingdom, North America and Australia. The incidence is usually small and sporadic, but up to half of the male animals on one farm may be affected clinically by the time they are one year old. Clinical lameness begins at three months to two years old, and very occasionally up to three years of age; some calves are obviously affected at birth. Aberdeen Angus cattle tend to be affected earlier than other breeds. Clinical evidence of the condition is almost entirely confined to the male.  相似文献   

10.
Husbandry of beef cattle requires animals that do not behave aggressively or timidly. The enzyme monoamine oxidase A and the coding gene (MAOA) play an important role in the complex regulation of behaviour. The complete coding region and a part of the non‐coding sequence of the bovine MAOA gene have been analysed in 20 German Angus and 20 German Simmental bulls and cows with the aim of detecting genetic variability. These two cattle breeds are known to differ regarding their behaviour during handling. Five single nucleotide polymorphisms (SNPs) were identified, three of which were found in the coding region of the gene (exons III and XV). One of the SNPs located in exon XV ( NC_007331.3 :g.80340C>T) was found to be a non‐synonymous mutation. The minor allele frequency of this resulting amino acid substitution was significantly different between 543 German Angus and 417 German Simmental calves (0.39 and 0.49, respectively). The potential functional impact of this polymorphism has been tested by in silico analysis, as well as by association analysis using behaviour scores of the genotyped calves for three behaviour tests that assessed the animals’ temperament during tethering, weighing or social separation. In silico analysis did not deliver consistent results arguing for or against a functional impact of the studied amino acid substitution on the function of the biological protein. No significant association was found between this MAOA polymorphism and the behaviour‐related scores analysed in the study.  相似文献   

11.
Because of the high variability of cattle infestation, selective breeding has been proposed to control three-host ticks in Africa in the same way as it has been implemented to control the one-host tick Boophilus microplus in Australia. Interbreeding (divergent selection experiment) between Gudali zebu cattle was performed at the Wakwa Research Centre, Adamawa, Cameroon to assess the feasibility and impact of such a selective breeding programme. Fifty cows (chosen out of 129) and 2 bulls (chosen out of 10) were selected according to their greater or lesser attractiveness for the tick Amblyomma variegatum, assessed by their infestation degree (ID, ratio between individual animal infestation and mean herd infestation). Half of the animals displayed a high ID (H) and the remainder a low ID (L). The presence of a suckling calf had a significant effect on the infestation of its dam, the udder of lactating cows being significantly less infested (P<0.001) because of a tick removal effect by the calves. Observed infestation data were therefore corrected to allow comparison between lactating and non-lactating cows. The ID of the cows was assessed on five occasions from 1992 to 1994: the consistency of the infestation hierarchy was good overall (P<0.001) despite high variability seen in some animals which would complicate the selection of cattle with low infestation. Four breeding groups were set up (LxL, LxH, HxL, HxH) and 40 calves were born in 1993 and 1994. There was a correlation (P<0.02-0.001) between liveweight (or age) and ID when the younger calves of the groups were 6 months old, but the correlation disappeared by the time the calves were all older than 1 year. There was no difference between the average ID of the calves from the four breeding groups, and no correlation was observed between dam ID and calf ID. The average ID of the 10 calves born of the dams with the lowest ID was however significantly lower than that of the 10 calves born of the dams with the highest ID (0.82 versus 1.15, P=0.03), but the difference was much less than that observed between the dams (0.35 versus 2.30, P=7x10(-9)). A positive correlation between dam ID and calf ID was found when only these 20 cows were taken into consideration (r=0.57, P<0.01). These results indicate that selective breeding of Gudali zebu cattle to produce animals with low infestation by the tick A. variegatum would be uncertain but that a more drastic selection of the breeders than that implemented in the present study may perhaps have some positive impact.  相似文献   

12.
南阳牛是我国五大良种黄牛品种之一,近些年国家越来越重视通过杂交改良的方法产生新品种培育工作,1986年引进了皮埃蒙特牛,与南阳牛进行杂交改良,通过30多年来的持续选育,横交固定形成了皮南牛新类群,它保持了南阳牛适应性好、耐粗饲的优点,同时继承了皮埃蒙特牛生长发育快、瘦肉率高的特点,但在皮南牛新品种培育过程中,仍存在核心...  相似文献   

13.
This study examines milk production and the effect of milk production and sex of calf on body weights and gains of red deer calves and hinds of the Iberian subspecies (Cervus elaphus hispanicus). Milk production was assessed in 14 hinds by weighing calves before and after suckling and by adjusting these values to the Gamma function. Gamma estimates of total milk production up to d 105 were similar to the amounts computed directly from double weighing. Hinds showed two types of lactation curve: 1) the standard mammal lactation curve, with an asymmetrical peak at wk 2 to 4 (Type I) and 2) decreasing curves with no peak (Type II). Although there was great interindividual variability, hinds with Type I curves showed a trend to produce more milk than those with Type II. The type of curve did not seem to affect weight variables of the calf or those of the dam. Calves that gained more weight consumed greater amounts of milk (P<.05). Males were heavier than females at birth (P<.05), but males did not differ from females in their weight at 105 d, milk consumption, and gain. Gender did not affect hind weight, but dams of male calves showed a trend to be lighter (P = .063) at d 105 than dams of female calves. Our results suggest that suckling differences found in other studies between male and female calves may not involve differences in milk production, although other rearing costs seem to affect hind weight losses. They also suggest that the curve type may not depend only, as reported, on the nutrition plane.  相似文献   

14.
We studied, by means of echocardiography in vivo, the cardiac consequences of the double-muscled character selection in beef cattle. Morphologic and functional echocardiographic variables were regularly estimated in 17 Friesian and 8 Belgian White and Blue calves during their growth. A total of 50 and 44 sets of data were collected in each group, respectively. Recordings were obtained, using 2-dimensional and M-mode echocardiography, and included measurements in long- and short-axis views of the heart. Most of the diastolic measurements of the left ventricle were not significantly different between breeds when normalized for body weight. To the contrary, systolic measurements of left ventricular wall thickness and dimensions were significantly (P less than or equal to 0.001) lower and greater, respectively, in Belgian White and Blue calves than in Friesian calves. This was interpreted as a result of significantly (P less than or equal to 0.001) lower left ventricular systolic functional indices in Belgian White and Blue than in Friesian calves. Echocardiographic evidence that the double-muscled selection in cattle induces alteration in morphologic variables of left ventricle was not found. However, results indicate that indices of left ventricular systolic function are lower in double-muscled calves than in calves with standard conformation.  相似文献   

15.
[目的]为筛选出适合凉州区肉牛繁殖的新模式。[方法]选择夏洛莱（XL）、利木辛（LM）、安格斯（AG）成年种公牛生产冻精,在西门塔尔和本地黄牛杂交一代（西本F1）成年母牛上实施人工授精,对杂交犊牛分月龄进行外貌体尺测定。[结果]XL冻精与西本F1代的后代体重、体高、体斜长、胸围、管围等生长指标均高于LM和AG后代指标。试验2方法是选择XL、LM、AG成年母牛生产冻胚,在成年母牛上实施胚胎移植,犊牛出生后进行外貌体尺测定。结果是：夏洛莱胚胎移植后代牛初生重、6月龄、12月龄体重、体高、体斜长、胸围、管围均高于利木辛与安格斯牛杂交后代（P〈0.01）。试验3方法是选择西杂F1和F2代母牛,用引进的XM（西门塔尔）牛X性控冻精实施人工授精,犊牛出生后统计相关数据。结果是：三组共授配母牛138头,情期妊娠75头,情期平均受胎率为54.1%,平均母犊率为90.3%。[结论]夏洛莱品种改良西杂一代牛后代生长发育比其余品种好;实施胚胎移植后,夏洛莱品种胚胎移植后代牛比其余品种在凉州区生长适应性强,适宜在该环境条件下生长;西门塔尔牛性控冻精的配种试验是成功的,是生产母犊的较好方法。  相似文献   

16.
In order to evaluate the degree of adaptability of three native cattle breeds to the natural pastures of southern Italy, the diurnal grazing behavioural pattern was monitored on 84 multiparous cows: 28 Podolian (14 suckling and 14 non-suckling), 28 Chianina (14 suckling and 14 non-suckling) and 28 Romagnola (14 suckling and 14 non-suckling). From August to October 2009 ten sessions of 9 h of behavioural observations were performed, from 07.00 to 19.00 h, through continuous focal animal recording method. Every hour, bite rate was recorded and bite mass and botanical preferences were determined on hand-plucked samples. Chianina cows selected proportionally more percent legumes than Romagnola and Podolian animals (P < 0.01), whereas Podolian cows chose a higher percentage of ferns (P < 0.05). Grasses represented a large proportion of the diet ingested by cows; these plant species were predominantly ingested in a late stage of maturation, which, in turn, induced the animals to take larger bites. Conversely, bite rate was positively related to high quality forages and negatively related to bite mass. Due to low genetic diversity and “allelo-mimetic” behaviour, no marked differences were observed among Chianina, Romagnola and Podolian breeds in terms of activity budget, ingestive behaviour and chemical composition of the diet as assessed through hand plucking. Based on rough estimations, all three breeds were able to reach the minimum ingestion levels needed to cover their maintenance and productive requirements of energy and protein. The three genotypes spent most of their time on grazing activity, followed by walking, whereas less time was spent resting. Animals were more active during mornings and afternoons in terms of grazing and walking (P < 0.05). Vocalizations were not influenced by breed but were significantly more frequent in cows with calf (4–5 months of age) than in non-suckling animals (P < 0.001). The presence of calf had no significant effect on the other behavioural variables. Cows from different breeds expressed preferential spatial relationships with other members of the herd. These results along with the low levels of agonistic and non-agonistic interactions occurring between herd-mates suggest that extensive systems based on grazing allow social stability, expression of species-specific behaviours and fulfilment of maintenance and productive requirements of cows from native breeds.  相似文献   

17.
Endectocide compounds are extensively used for broad-spectrum parasite control and their topical administration to cattle is widespread in clinical practice. Pour-on formulations of moxidectin, ivermectin, eprinomectin and doramectin (DRM) are marketed internationally for use in cattle. However, variability in antiparasitic efficacy and pharmacokinetic profiles has been observed. Although the tissue distribution pattern for different endectocide molecules given subcutaneously to cattle has been described, only limited information on drug concentration profiles in tissues of parasite location after topical treatment is available. Understanding the plasma and target tissue kinetics for topically-administered endectocide compounds is relevant to optimise their therapeutic potential. The current work was designed to measure the plasma and gastrointestinal (GI) concentration profiles of DRM following its pour-on administration to calves. The influence of natural licking behaviour of cattle on DRM concentration in mucosal tissue and luminal content of different GI sections was evaluated. The trial was conducted in two experimental phases. In Phase I, the DRM plasma kinetics was comparatively characterised in free-licking and in 2-day licking-restricted (non-licking) calves. The pattern of distribution of topical DRM to mucosal and luminal contents from abomasum, duodenum, ileum, caecum and spiral colon was assessed in free-licking and non-licking calves restricted over 10 days post-administration (Phase II). The prevention of licking caused marked changes on the plasma and GI kinetics of DRM administered pour-on. In 2-day licking restricted calves, DRM systemic availability was significantly lower (29%) than in free licking animals during the first 9 days post-treatment. Following a 10-day long licking restriction period, DRM concentrations profiles in both mucosal tissue and luminal contents of the GI tract were markedly higher in animals allowed to lick freely. This enhancement in drug concentrations in free-licking compared to non-licking calves, was particularly pronounced in the abomasal (38-fold higher) and duodenal (six-fold higher) luminal content. As shown earlier for ivermectin, licking behaviour may facilitate the oral ingestion of topically-administered DRM in cattle. This would be consistent with the marked lower drug concentration profiles measured in the bloodstream and GI tract of the animals prevented from licking. The work reported here provides relevant information on the pattern of DRM distribution to the GI tract after pour-on treatment, and contributes to understand the variability observed in the antiparasitic persistence of topically-administered endectocides in cattle. The implications of natural licking in topical treatments are required to be seriously assessed to achieve optimal parasite control and to design parasitological and pharmacological studies within the drug approval process.  相似文献   

18.
为了研究不同肉牛品种杂交改良西门塔尔杂种牛的效果,筛选出产肉量高、肉质好、抗逆性强的品种杂交组合,为大规模开展杂交提供依据,试验采用红安格斯、利木赞、夏洛莱(法系)、德国黄牛4个品种牛,分别杂交西门塔尔杂种母牛,产犊后从每个杂交组合中选择11头断奶小公牛,在相同饲养管理条件下持续育肥至18月龄,并进行屠宰和肉质评定。结果表明:红安西杂组合杂交效果最好,其次是利西杂及夏西杂,德黄西杂组合杂交效果较差。说明在生产实际中,如果采用断奶小公牛持续育肥至18月龄时出栏、屠宰,应优先选择红安格斯×西门塔尔杂交组合。  相似文献   

19.
The objective of this study was to characterize breeds representing diverse biological types for birth and weaning traits in crossbred cattle (Bos taurus). Gestation length, calving difficulty, percentage of unassisted calving, percentage of perinatal survival, percentage of survival from birth to weaning, birth weight, weaning weight, BW at 205 d, and ADG was measured in 1,370 calves born and 1,285 calves weaned. Calves were obtained by mating Hereford, Angus, and MARC III (1/4 Hereford, 1/4 Angus, 1/4 Pinzgauer, and 1/4 Red Poll) mature cows to Hereford or Angus (British breeds), Norwegian Red, Swedish Red and White, Wagyu, and Friesian sires. Calves were born during the spring of 1997 and 1998. Sire breed was significant for gestation length, birth weight, BW at 205 d, and ADG (P < 0.001). Offspring from Swedish Red and White and Friesian had the shortest gestation length (282 d), whereas offspring from Wagyu sires had the longest gestation length (286 d). Progeny from British breeds were the heaviest at birth (40.5 kg) and at 205 d (237 kg), and grew faster (0.97 kg/d) than offspring from other breeds. Offspring from Wagyu sires were the lightest at birth (36.3 kg) and at 205 d (214 kg), and had the slowest growth (0.91 kg/d). Dam breed was significant for gestation length (P < 0.001), birth weight (P = 0.009), BW at 205 d, and ADG (P < 0.001). Offspring from Hereford cows had the longest gestation length (284 d), whereas offspring from Angus cows had the shortest (282 d). Offspring from MARC III cows were the heaviest at birth (39.4 kg) when compared with offspring from Hereford (38.2 kg) and Angus (38.6 kg) cows. Progeny from Angus cows were the heaviest at 205 d (235 kg) and grew faster (0.96 kg/d), whereas offspring from Hereford cows were the lightest at 205 d (219 kg) and were the slowest in growth (0.88 kg/d). Sex was significant for gestation length (P = 0.026), birth weight, BW at 205 d, and ADG (P < 0.001). Male calves had a longer gestation length (284 d) when compared with female calves (283 d). Males were heavier than females at birth and at 205 d, and grew faster. Sire breed effects can be optimized by selection and use of appropriate crossbreeding systems.  相似文献   

20.
AIM: To investigate cases of coat-colour dilution and hypotrichosis in a group of Hereford x Friesian crossbred calves, and to define the underlying molecular genetics of the disorder. METHODS: The investigation was predicated on the hypothesis that this disorder was similar to a known dominantly inherited disorder of calves of black breeds crossed with Simmental cattle, for which there were candidate gene mutations. Sequence analyses of PCR amplicons from exon 1 and exon 11 of the premelanosome protein 17 gene (PMel17) were carried out. Restriction enzyme digestions of amplicons were followed using electrophoresis of digested fragments. RESULTS: It was shown that an affected calf and its Hereford sire were heterozygous for a three-base deletion in exon 1 of the PMel17 gene. These two animals were also heterozygous for a second mutation in exon 11 of the PMel17 gene. Four other related animals were likewise heterozygous for both mutations in the sire's herd of origin. CONCLUSIONS: Coat-colour dilution and hypotrichosis in Hereford crossbred calves in New Zealand is the same genetic disorder as that previously described in Simmental crossbred calves, and is linked to mutations in the PMel17 gene.  相似文献   

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