Reproductive disorders in dairy cattle: I. Respective influence of herds, seasons, milk yield and parity

This study was performed in two large dairy units (with 130 and 213 calving cows each) during one year. The objectives were to investigate 1) epidemiological patterns of main post-partum reproductive disorders (metritis, post-partum and post-service anestrus, repeat breeding and embryonic death) and 2) the impact of herd, calving season, milk yield and parity on these patterns. Approximately 20% of the cows in both herds were not affected by any of the disorders. Prevalence of metritis was high (32 to 44%) and appeared influenced by the herds' conditions interacting with calving months and milk yield effects. Cyclic post-partum anestrus incidence was also essentially affected by the herd effect with an added seasonal interaction. Other disorders in both herds were also primarily subjected to the seasonal effect. Individual milk yield and parity only marginally affected the epidemiological patterns. We concluded that even in similar environmental conditions, no general patterns of incidence of reproductive disorders can be drawn and that they are essentially dependent on the characteristics of each herd management.     

Variables associated with peripartum traits in dairy cows. II. Interrelationships among disorders and their effects on intake of feed and on reproductive efficiency

Daily individual voluntary intakes of dry matter (DM % of body weight) and estimated net energy (ENE, Mcal/100 kg) by 89 Holstein cows were compared between day 220 of gestation and day 30 postpartum over a 21-month period. The purpose was to compare effects of diet and health status (control vs. abnormal) on intakes of DM and ENE. The cows were fed either chopped hay, hay crop silage (HCS) or corn silage (CS). Compared to controls, voluntary intakes of DM and ENE were decreased (most to least) in cows with fat cow syndrome (FCS), parturient paresis (PP), mastitis (MST), retained fetal membranes-metritis (RFM-M), and displaced abomasum (DA) prepartum and FCS, DA, PP, RFM-M and MST peripartum. Cows fed hay had a lower incidence of RFM-M (28%) than cows fed HCS (57%) and CS (47%) as well as superior reproductive efficiency subsequently (89% conceived vs. 72% and 78%, respectively).     

Gonadotropin releasing hormone therapy in functional infertility of dairy cattle

Effects of gonadotropin-releasing hormone (GnRH) on conception rate was tested in 379 repeat-breeders in nine large dairy herds in Louisiana. Cattle with three or more services were treated intramuscularly with GnRH at the time of artificial insemination. The conception rate for the repeat-breeders treated with GnRH was significantly greater than for the controls (56 vs 40%). Furthermore, repeat-breeders that were treated with GnRH for two consecutive times at insemination resulted in a 53% increase in conception rate over the controls.     

Hormone and metabolite differences between lactating beef and dairy cattle

Hourly blood samples were taken throughout a 24h (metabolites) or 48h (hormones) period from three lactating beef (Hereford-cross) and three dairy (Friesian) cows which had been matched for age, stage of lactation (89–110 days) and diet (0.55 kg hay + 4.95 kg concentrates, twice daily). During the first 15 weeks of lactation the beef cows (B) gained weight and gave a poor yield of milk, whereas the dairy animals (D) lost weight but gave a good yield of milk. Significantly higher circulating levels of growth hormone (D = 4.2 ± 0.5 B = 1.5 ± 0.2 ng/ml ± SEMP < 0.005), non-esterified fatty acids (D = 311.0 ± 48.3 B = 181.3 ± 18.9 μEq/1 P<0.0001) and β-hydroxybutyric acid (D= 0.170 ± 0.011 B=0.093 ± 0.0007 mg/mlP<0.0005) were found in the dairy cows, whereas in the beef animals there were significantly higher concentrations of prolactin (D = 8.3 ± 1.1 B = 15.4 ± 1.8 ng/mlP<0.025), insulin (D = 9.5 ± 0.08 B = 28.8 ± 2.6 μU/mlP<0.0001) and glucose (D = 0.654 ± 0.008 B= 0.705 ± 0.009 mg/mlP<0.025). No significant difference in L-lactic acid levels was found at this stage of lactation (D = 0.097 ±0.003 B =0.117 ± 0.006 mg/mlP<0.05).     

Variation in sex ratio between progeny groups in dairy cattle

Summary Highly significant differences between progeny groups have been found in the Israeli-Frisian breed of cattle. The standard deviations between groups in the proportion of males was estimated to be 1.5%. Significant correlations between sire and son and between half-sibs in the sex ratio of their progeny suggest that the differences may have a genetic basis.     

Epigenetic disorders and altered gene expression after use of Assisted Reproductive Technologies in domestic cattle

The use of Assisted Reproductive Technologies (ARTs) in modern cattle breeding is an important tool for improving the production of dairy and beef cattle. A frequently employed ART in the cattle industry is in vitro production of embryos. However, bovine in vitro produced embryos differ greatly from their in vivo produced counterparts in many facets, including developmental competence. The lower developmental capacity of these embryos could be due to the stress to which the gametes and/or embryos are exposed during in vitro embryo production, specifically ovarian hormonal stimulation, follicular aspiration, oocyte in vitro maturation in hormone supplemented medium, sperm handling, gamete cryopreservation, and culture of embryos. The negative effects of some ARTs on embryo development could, at least partially, be explained by disruption of the physiological epigenetic profile of the gametes and/or embryos. Here, we review the current literature with regard to the putative link between ARTs used in bovine reproduction and epigenetic disorders and changes in the expression profile of embryonic genes. Information on the relationship between reproductive biotechnologies and epigenetic disorders and aberrant gene expression in bovine embryos is limited and novel approaches are needed to explore ways in which ARTs can be improved to avoid epigenetic disorders.     

Postpartum anestrus in dairy cattle

Fertility of the postpartum period is negatively influenced by the incidence of anestrus. The latter condition is characterized by the absence of estrous behavior, which may be an indication of suboptimal conditions (e.g., inadequate peripartum nutrition) or pathologic conditions (e.g., chronic debilitating diseases or uterine and ovarian diseases). Although initiation of ovarian follicular growth in the postpartum period is generally not affected, subsequent development (deviation) and the fate of the dominant follicle are the primary factors that affect reestablishment of ovarian cyclicity. Anestrus can be classified based on the three functional states of follicular development; that is, follicle emergence, deviation, and ovulation. Prevention of anestrus is preferable to treatment and can be achieved in part by maintaining a healthy periparturient period. To better understand the etiology of anestrus and its prevention, research is urgently needed in the following three areas: the role of peripartum disease conditions that influence reproduction, genes involved in ovulation, and the influence of proteins (e.g., leptin) that appear to be important links between metabolic signals and the neuroendocrine axis.     

Syntenic conservation between humans and cattle. II. Human chromosome 12

Bovine X hamster and bovine X mouse hybrid somatic cells have been used to investigate the syntenic relationship of nine loci in the bovine that have homologous loci on human chromosome 12. Eight loci, including A2M, GLI, HOX3, IFNG, INT1, KRAS2, NKNB, and PAH, were assigned to the previously identified bovine syntenic group U3 represented by GAPD. However, a single locus from the q-terminus of HSA 12, ALDH2, mapped to a new, previously unidentified autosomal syntenic group. These results indicate the existence of a very large ancestral syntenic group spanning from the p-terminus to q24 of HSA 12 and containing over 4% of the mammalian genome. Additionally, the results predict that ALDH2 is distal to PAH and IFNG on HSA 12, the type II keratin gene complex will reside between q11 and q21 of HSA 12, A2M will map to MMU 6, and LALBA and GLI will map to MMU 15.     

Respiratory disorders in Manitoba cattle farmers.

A group of 76 cattle farmers from southern Manitoba answered the National Heart, Lung, and Blood Institute questionnaire on respiratory symptoms and supplementary questions on farming and farming-related syndromes. Lung function was tested, serum was examined for precipitating antibodies, and skin testing with common allergens was performed. Analysis of the men''s answers revealed a high prevalence of chronic respiratory symptoms among the farmers in all categories of smoking history, and the presence of these symptoms was significantly associated with a history of symptoms related to handling mouldy hay or grain; 51% of the men had chronic symptoms and 55% had symptoms related to crop handling. In seven farmers (9%) the symptoms related to crop handling suggested an attack of farmer''s lung. One other farmer, with a history of illness after handling mouldy hay, had a reduced total lung capacity, and in 18 the ratio of the forced expiratory volume in the first second to the forced vital capacity was lower than predicted. Precipitating antibodies against Thermoactinomyces were absent in all farmers, but two farmers had antibodies against Aspergillus ruber. Immediate hypersensitivity was found in 16 (21%) of the farmers; sensitivity to Dermatophagoides farinae was commonest.     

Reproductive traits in Nubian dairy goats

For 12 months, ten Nubian doe goats were examined daily for oestrus and blood was obtained twice weekly for serum progesterone (P) analysis. Before the onset of regular ovulatory cycles in the autumn, brief increases in serum P were noted. Ovulation without oestrus was associated with the onset of the breeding season in five of 13 instances. Ovarian activity as assessed by corpus luteum (CL) function began in either September or October and ceased in either January or February in nonpregnant does. CL function was absent postpartum until the beginning of the next breeding season. An instance of male pseudohermaphroditism and mucometra is noted.     

Association between Coxiella burnetii seropositivity and abortion in dairy cattle of Northern Italy

Coxiella burnetii, the agent of Q fever in humans, has been associated with abortion in cattle. In this study 650 sera from cattle with abortion and 600 randomly-selected control sera were examined for antibodies to C. burnetii by ELISA. Two hundred and ninety-two (44.9%) out of 650 animals which experienced abortion were seropositive versus 132 (22%) out of 600 of the control group. A statistically significant difference resulted from the comparison of the seroprevalence of aborted cattle with that of controls (p < 0.001). Moreover, a significant higher prevalence was disclosed in cattle which aborted during late gestation (p < 0.002) and in the autumn (p < 0.001).     

Serum post-albumins and fertility in dairy cattle

Blood samples from 180 Guernsey cows and 599 Holstein cows were typed for post-albumins (Poa). The genotypes were compared for breeding efficiency, mean return interval, anestrus interval, service interval, gestation length and lactation length. Poa SF cows had a significantly shorter (P < 0.01) mean return interval than SS cows. The effect is associated with order of insemination, but is independent of lactation number. None of the other parameters showed genotypic differences.     

Causal relationships between milk quality and coagulation properties in Italian Holstein-Friesian dairy cattle

Background

Recently, selection for milk technological traits was initiated in the Italian dairy cattle industry based on direct measures of milk coagulation properties (MCP) such as rennet coagulation time (RCT) and curd firmness 30 min after rennet addition (a₃₀) and on some traditional milk quality traits that are used as predictors, such as somatic cell score (SCS) and casein percentage (CAS). The aim of this study was to shed light on the causal relationships between traditional milk quality traits and MCP. Different structural equation models that included causal effects of SCS and CAS on RCT and a₃₀ and of RCT on a₃₀ were implemented in a Bayesian framework.

Results

Our results indicate a non-zero magnitude of the causal relationships between the traits studied. Causal effects of SCS and CAS on RCT and a₃₀ were observed, which suggests that the relationship between milk coagulation ability and traditional milk quality traits depends more on phenotypic causal pathways than directly on common genetic influence. While RCT does not seem to be largely controlled by SCS and CAS, some of the variation in a₃₀ depends on the phenotypes of these traits. However, a₃₀ depends heavily on coagulation time. Our results also indicate that, when direct effects of SCS, CAS and RCT are considered simultaneously, most of the overall genetic variability of a₃₀ is mediated by other traits.

Conclusions

This study suggests that selection for RCT and a₃₀ should not be performed on correlated traits such as SCS or CAS but on direct measures because the ability of milk to coagulate is improved through the causal effect that the former play on the latter, rather than from a common source of genetic variation. Breaking the causal link (e.g. standardizing SCS or CAS before the milk is processed into cheese) would reduce the impact of the improvement due to selective breeding. Since a₃₀ depends heavily on RCT, the relative emphasis that is put on this trait should be reconsidered and weighted for the fact that the pure measure of a₃₀ almost double-counts RCT.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-015-0123-7) contains supplementary material, which is available to authorized users.     

Hoof overgrowth in Holstein--Friesian dairy cattle

The genetic etiology of hoof overgrowth, a widespread problem in Holstein-Friesian cattle, was examined. Although all four feet are affected, the hind feet usually have a greater degree of overgrowth. There is a distinct age tendency for the trait; the younger cows' hooves grow faster than those of the older cows, but the overgrowth in older cows reaches greater proportions. Analysis of variance of chi-square frequency tests showed that there is a component of heritability involved in the expression of the trait, but that it follows a more complex model than a simple autosomal recessive gene would show.     

A genome map of divergent artificial selection between Bos taurus dairy cattle and Bos taurus beef cattle

A number of cattle breeds have become highly specialized for milk or beef production, following strong artificial selection for these traits. In this paper, we compare allele frequencies from 9323 single nucleotide polymorphism (SNP) markers genotyped in dairy and beef cattle breeds averaged in sliding windows across the genome, with the aim of identifying divergently selected regions of the genome between the production types. The value of the method for identifying selection signatures was validated by four sources of evidence. First, differences in allele frequencies between dairy and beef cattle at individual SNPs were correlated with the effects of those SNPs on production traits. Secondly, large differences in allele frequencies generally occurred in the same location for two independent data sets (correlation 0.45) between sliding window averages. Thirdly, the largest differences in sliding window average difference in allele frequencies were found on chromosome 20 in the region of the growth hormone receptor gene, which carries a mutation known to have an effect on milk production traits in a number of dairy populations. Finally, for the chromosome tested, the location of selection signatures between dairy and beef cattle was correlated with the location of selection signatures within dairy cattle.     

Sterigmatocystin in dairy cattle feed contaminated with Aspergillus versicolor.

Sterigmatocystin (7.75 micrograms/g of feed) and a high-propagule-density of Aspergillus versicolor were detected in feed associated with acute clinical symptoms of bloody diarrhea and death in dairy cattle. Nine isolates of A. versicolor from the feed produced 13 to 89 micrograms of sterigmatocystin per g on cracked corn and lower amounts in liquid culture. This is the first report of sterigmatocystin in dairy cattle feed in the United States.     

Relationship between progesterone concentrations in milk and blood and time of ovulation in dairy cattle

The objective of this study was to investigate whether monitoring progesterone concentrations in milk and blood plasma can be used to predict time of ovulation in dairy cattle. Whole milk was sampled twice daily and blood samples were collected once a day before the morning milking. Ovulation was assessed by trans-rectal ultrasonography at 4h intervals beginning from the end of estrus. For a parameter to be useful as predictor for time of ovulation, it should be precise (i.e. variation between animals should not exceed 12h). In milk, progesterone concentration dropped <15 ng/ml at 97.7+/-17.8h (range: 54-126 h) before ovulation, to <5 ng/ml at 79.7+/-11.2h (range: 54-98) before ovulation to decline further to <2n g/ml at 70.7+/-16.8h (range: 38-90 h) before ovulation (n=20). In plasma, progesterone concentration dropped to <4ng/ml 90.5+/-19.6h (range: 66-138 h) before ovulation and to <2 ng/ml at 75.0+/-12.2 h (range: 50-98) before ovulation. These intervals were not influenced by parity, milk production or days in milk. In conclusion, monitoring of progesterone alone is not sufficient to predict ovulation because of the large variation in timing of decrease of progesterone concentrations relative to ovulation between animals. At best the range is about 2 days.