Foot lesions in lame cows on 10 dairy farms in Ireland

Background

Little is known about foot lesions in dairy cattle in Ireland, managed under a pasture based system with housing during the winter and grazing for the rest of the year. Ten Irish dairy herds, with a lameness prevalence ranging from 9 to 17 % were locomotion scored routinely during the 2013 grazing season. Lame cows were foot trimmed and foot lesions recorded.

Findings

11.8 % and 89.6 % of cows had lesions recorded on front and hind feet respectively. No lesions were found in 6.9 % of cows. Sole haemorrhage and white line disease were the most prevalent lesions, and overall 76.8 % of lesions affecting the claw horn were diagnosed on the lateral hind claw.

Conclusions

Treatment success, as measured by improved LS post treatment, was not significantly affected by the LS prior to foot trimming, the presence of lesions or the type of lesion identified. Exposure to both risk factors for lameness at housing and pasture may have resulted in the development of a combination of foot lesions typically associated with zero-grazing or all-year-round grazing management systems.     

Metabolic and endocrine profiles and reproductive parameters in dairy cows under grazing conditions: effect of polymorphisms in somatotropic axis genes

Background

The present study hypothesized that GH-AluI and IGF-I-SnabI polymorphisms do change the metabolic/endocrine profiles in Holstein cows during the transition period, which in turn are associated with productive and reproductive parameters.

Methods

Holstein cows (Farm 1, primiparous cows, n = 110, and Farm 2, multiparous cows, n = 76) under grazing conditions were selected and GH and IGF-I genotypes were determined. Blood samples for metabolic/endocrine determinations were taken during the transition period and early lactation in both farms. Data was analyzed by farm using a repeated measures analyses including GH and IGF-I genotypes, days and interactions as fixed effects, sire and cow as random effects and calving date as covariate.

Results and Discussion

Frequencies of GH and IGF-I alleles were L:0.84, V:0.16 and A:0.60, B:0.40, respectively. The GH genotype was not associated with productive or reproductive variables, but interaction with days affected FCM yield in multiparous (farm 2) cows (LL yielded more than LV cows) in early lactation. The GH genotype affected NEFA and IGF-I concentrations in farm 1 (LV had higher NEFA and lower IGF-I than LL cows) suggesting a better energy status of LL cows.There was no effect of IGF-I genotype on productive variables, but a trend was found for FCM in farm 2 (AB cows yielded more than AA cows). IGF-I genotype affected calving first service interval in farm 1, and the interaction with days tended to affect FCM yield (AB cows had a shorter interval and yielded more FCM than BB cows). IGF-I genotype affected BHB, NEFA, and insulin concentrations in farm 1: primiparous BB cows had lower NEFA and BHB and higher insulin concentrations. In farm 2, there was no effect of IGF-I genotype, but there was an interaction with days on IGF-I concentration, suggesting a greater uncoupling somatropic axis in AB and BB than AA cows, being in accordance with greater FCM yield in AB cows.

Conclusion

The GH and IGF-I genotypes had no substantial effect on productive parameters, although IGF-I genotype affected calving-first service interval in primiparous cows. Besides, these genotypes may modify the endocrine/metabolic profiles of the transition dairy cow under grazing conditions.     

Risk factors for interdigital dermatitis and heel erosion in dairy cows kept in cubicle houses in The Netherlands

Risk factors concerning both the pasture and housing seasons for interdigital dermatitis and heel-horn erosion (IDHE) were studied in dairy cows in a cross-sectional study in The Netherlands. The study population included 2,326 cows (41 herds) and 2,751 cows (46 herds) for the pasture and housing seasons, respectively. Of these animals, 545 (23%) showed serious lesions of IDHE (stages 2 and 3) at the end of the pasture season and 1,269 (46%) during housing. Logistic regression of the pasture study indicated that increased parity, solid concrete floor, restricted grazing time, and herd trimming at long intervals were associated with an increased odds of IDHE, while dry cows and lactating cows within 30 days after calving as well as cows on a slatted floor with manure scraper, and grassland with mixed type of soil were associated with lower odds. In the housing study, odds of IDHE increased with parity, administering low- or medium-energy roughage, and introduction of dry cows into the lactating herd at >2 weeks before calving. The presence of long cubicles, knee-bumpers installed in cubicles as well as rearing calves and heifers within the dairy cows' accommodation decreased the odds of IDHE.     

Identification of factor XI deficiency in Holstein cattle in Turkey

Background

Factor XI (FXI) is a plasma protein that participates in the formation of blood clots. Factor XI deficiency is autosomal recessive hereditary disorder that may be associated with excess bleeding in Holstein cattle.

Methods

In this study, 225 Holstein cows reared in Turkey were screened in order to identify FXI genotypes. DNA extractions were obtained from the fresh blood of the cows. Amplicons of FXI exon 12 were obtained by Polymerase Chain Reaction (PCR), and analyzed by 2% agarose gel electrophoresis stained with ethidium bromide. Additionally, all cows were confirmed by DNA sequencing to determine whether or not there was a mutant allele.

Results

Carriers of the FXI deficiency have two DNA fragments of 320 bp and 244 bp in size. The results of our study demonstrated that only four out of the 225 Holstein cows tested in Turkey carried the FXI deficiency. The frequency of the mutant FXI allele and the prevalence of heterozygous cows were found as 0.9% and 1.8%, respectively.

Conclusion

The DNA-based test determines all genotypes, regardless of phenotype or FXI activity. The mutation responsible for the FXI deficiency had not been detected in Holstein cattle in Turkey before prior to this study. The frequency of the mutant FXI allele needs to be confirmed by carrying out further analyses on cattle in Turkey and the selection programs should be developed to eliminate this genetic disorder.     

Effects of grazing adaptation on herbage intake,milk production,and body weight change in lactating dairy cows after turning out to pasture in early spring

The present study investigated the effects of adaptation to grazing in early spring on the herbage intake, milk production, and body weight changes in lactating dairy cows. The experiment included 12 Holstein lactating cows during early spring. Six cows were allowed to gradually adapt to grazing (ADP) over 10 days. They were allowed to graze on a pasture for 4 h during the first week and for 19 h during the remaining 3 days (adaptation period). During the 10-day period, the remaining six cows were housed in a barn (CON). Cows in both groups received adequate silage, hay, and concentrate during the adaptation period. Subsequently, cows in both groups were allowed to graze together for 19 h for 4 weeks (experimental period). No cow received supplements during the experimental period. In the first week of the experimental period, the ADP cows showed a higher herbage intake than the CON cows. During the subsequent weeks, there were no differences in herbage intake between the two groups. At the start of the experimental period, milk production and body weight of the ADP cows were higher than those of the CON cows, and this difference lasted until the end of the experiment.     

Mammary-derived growth inhibitor in lactation and involution.

Presence of mammary-derived growth inhibitor (MDGI) in mammary tissue of lactating and involuted cows was investigated. Eighteen lactating, non-pregnant high-producing Holstein cows were randomly assigned to 3 experimental groups of 6 cows each. Cows of the first group were slaughtered while in lactation. Cows of the second group were slaughtered at 2-3 d, and the others at 4-8 d following sudden cessation of milking. Cessation of milking occurred at approximately 300 d in lactation. Western blot analysis revealed the presence of MDGI in the cytosolic and microsomal fractions of mammary tissue homogenates. High levels of MDGI were detected in mammary tissue obtained from lactating non-pregnant cows. A dramatic reduction in MDGI was observed in early involution (2-3 or 4-8 d following cessation of milking). These data suggest that a relationship exists between MDGI levels and the physiological status of the gland. Lack of MDGI may play a role during the processes of mammary involution and development prior to parturition.     

Dairy cow defecation and urination frequency and spatial distribution in relation to time-limited grazing

The objective of this paper was to investigate the effect of limited grazing time on urination and defecation frequency, spatial distribution of excrement in the paddock, and the resulting nitrogen balance at animal and field level. During a 6-week period in early summer, 60 Holstein Frisian dairy cows (31.0 ± 5.4 kg ECM) were randomly allocated to three different treatments, with grazing at clover-grass pasture during daytime for 4, 6.5 or 9 h daily. Indoor feeding, with a mixture of roughage and concentrates (13% crude protein), was restricted for treatment 4 and 6.5 h to the amount the 9-h treatment could eat. Cows allowed grazing at pasture for 4 h moved more rapidly during pasture, moved longer distance per active hour and used a higher proportion of the time eating, both at pasture and indoor, than the cows allowed longer time at pasture. Limiting the grazing time had no influence on the urination (mean = 0.26) and defecation (mean = 0.37) frequency per cow per hour during pasture. Even though the proportion of time active (eating, drinking, standing or walking), and the actual time active during pasture was different for the treatments, the frequency of urination and defecation per active hour was also unaffected by the treatments. Urine and faeces were distributed in the pasture, without specific hot-spots. The estimated daily N-balance at animal level showed increased N excretion with time at pasture. Assuming that excretion follows the active periods during the day and 7000 kg DM foliage is available on yearly basis, this would result in total excretion at field level of 58, 86 and 108 kg N per ha respectively for treatment 4, 6.5 and 9 h. The results of this experiment show that it is possible to reduce the nitrogen excretion in a grazing system by restricting the grazing time of dairy cows together with restricted indoor feeding while maintaining high foliage intake.     

The effects of supplementing <Emphasis Type="Italic">Acacia mearnsii</Emphasis> tannin extract on dairy cow dry matter intake,milk production,and methane emission in a tropical pasture

The study assessed the effect of Acacia mearnsii tannin extract supplementation grazing dairy cows on dry matter (DM) intake, enteric methane (CH₄) emission, and performance. Twelve Holstein cows were divided into two groups and subjected to two treatments that consisted of millet pasture (Pennisetum glaucum L.) plus supplementation with 6 kg of concentrate (750-g/kg ground corn and 250-g/kg soybean meal) including or excluding 120-g tannin extract. The trial design was a double reversal using three periods of 28 days each, with 21 days for the adaption period, and 7 days for sample collection. Herbage intake was measured using the n-alkane technique, and daily CH₄ emission was measured with the sulfur hexafluoride tracer gas technique. Individual total DM intake (mean = 17.1 kg/day), herbage DM intake (mean = 11.8 kg/day), and milk production (mean = 19.2 kg/day) were similar between treatments. CH₄ emission significantly decreased (32%, P < 0.05) in the animals supplemented with tannin extract, compared to non-supplemented animals. On the other hand, as proportion of DM intake or milk production, methane emission tended to decrease in tannin-supplemented animals. Supplementing dairy cows grazing a millet pasture with 120-g tannin extract reduced daily CH₄ emission without affecting animal performance.     

Influence of the calf presence during milking on dairy performance,milk fatty acid composition,lipolysis and cheese composition in Salers cows during winter and grazing seasons

The milking of Salers cows requires the presence of the calf. The removal of the calf would simplify the milking routine, but it could also modify the milk yield and the milk and cheese composition. Therefore, the aim of this experiment was to evaluate the effect of calf presence during milking during sampling period (winter or grazing periods), on dairy performance, milk fatty acid (FA) composition, lipolysis and cheese yield and composition. Nine and 8 Salers lactating cows were milked in the presence (CP) or absence (CA) of their calves respectively. During winter, the cows were fed a hay‐based diet and then they only grazed a grassland pasture. Calf presence during milking increased milk yield and milk 16:0 concentration and decreased milk fat content and milk total odd‐ and branched‐chain FA (OBCFA) concentrations. Calf presence only increased initial lipolysis in milk collected during the winter season. Milk from CP cows compared to CA cows resulted in a lower cheese yield and ripened cheeses with lower fat content. Milk from the grazing season had lower saturated medium‐chain FA and OBCFA concentrations and higher 18:0, cis‐9‐18:1, trans‐11‐18:1 and cis‐9, trans‐11‐CLA concentrations than that from the winter season. Initial milk lipolysis was higher in the winter than in the grazing season. These variations could be due to seasonal changes in the basal diet. Furthermore, the effect of calf presence during milking on milk fat composition was lower than that on dairy performance, cheese yield and composition. Removing the calf during the milking of Salers cows seems feasible without a decrease in milked milk, and with a positive effect on cheese yield and fat content, under the condition that we are able to select cows having the capacity to be milked easily without the calf.     

Housing system and herd size interactions in Norwegian dairy herds; associations with performance and disease incidence

Background

According to the Norwegian animal welfare regulations, it has been forbidden to build new tie-stall barns since the end of 2004. Previous studies have shown that cow performance and health differ between housing systems. The interaction between housing system and herd size with respect to performance and disease incidence has not been evaluated.

Methods

Cow performance and health in 620 herds housed in free-stall barns were compared with in 192 herds housed in tie-stall barns based on a mail survey and data from the Norwegian Dairy Herd Recording and Cattle Health Systems. The housing systems herds were comparable with respect to herd size (15-55 cows). Associations between performance/disease incidence and housing system, herd size and year of building the cow barn were tested in general linear models, and values for fixed herd size of 20 and 50 cows were calculated. On the individual cow level mixed models were run to test the effect of among others housing system and herd size on test-day milk yield, and to evaluate lactation curves in different parities. All cows were of the Norwegian Red Breed.

Results

Average milk production per cow-year was 134 kg lower in free-stall herd than in tie-stall herds, but in the range 27-45 cows there was no significant difference in yields between the herd categories. In herds with less than 27 cows there were increasingly lower yields in free-stalls, particularly in first parity, whereas the yields were increasingly higher in free-stalls with more than 45 cows.In free-stalls fertility was better, calving interval shorter, and the incidence rate of teat injuries, ketosis, indigestions, anoestrus and cystic ovaries was lower than in tie-stalls. All of these factors were more favourable in estimated 50-cow herds as compared to 20-cow herds. In the larger herd category, bulk milk somatic cell counts were higher, and the incidence rate of mastitis (all cases) and all diseases was lower.

Conclusion

This study has shown that there is an interaction between housing system and herd size, and that performance and health is not universally better in small free-stalls than in tie-stalls.     

The Effect of Pasture Nitrate Concentration and Concentrate Intake after Turnout on Embryo Growth and Viability in the Lactating Dairy Cow

This study investigated the effects on embryo growth and survival rate of feeding heavily‐fertilised spring grass, containing high levels of quickly‐degradable nitrogen, to pregnant cows. Forty‐eight lactating Holstein cows between 2 and 8 weeks pregnant were turned‐out, after a one‐week transition period onto high‐ or low‐nitrate pasture and fed a high‐ or low‐concentrate supplement. Cows grazing the High nitrate pasture had significantly higher milk and plasma urea concentrations than cows grazing the Control pasture, while cows which were fed less concentrate had a notably higher plasma ammonia. However, there was no evidence that an increased quickly‐degradable nitrogen (QDN) intake from pasture affected embryo survival or growth from 20 days onwards. This suggests that the impact of turnout on fertility mainly affects ovulation, fertilisation and/or the early embryo.     

A hereditary disposition for bovine peripheral nerve sheath tumors in Danish Holstein cattle

Background

Peripheral nerve sheath tumors (PNSTs) are frequently found in Danish cattle at slaughter. Bovine PNSTs share several gross and histopathological characteristics with the PNSTs in humans with heritable neurofibromatosis syndromes. The aim of the present study was to investigate a possible hereditary disposition to PNSTs in dairy cattle by statistical analysis performed on data from 567 cattle with PNSTs. Furthermore, a preliminary genome-wide association study (GWAS) was performed on DNA isolated from 28 affected and 28 non-affected Holstein cows to identify loci in the bovine genome involved in the development of PNSTs.

Results

PNSTs were significantly more common in the Danish Holstein breed than in other breeds with 0.49% of Danish Holsteins slaughtered during an eight-year-period having PNSTs. PNSTs also occurred significantly more frequently in the offspring of some specific Holstein sires. Examination of three generation pedigrees showed that these sires were genetically related through a widely used US Holstein sire. The PNSTs included in GWAS were histologically classified as neurofibroma-schwannoma (43%), schwannoma (36%) and neurofibroma (21%) and derived from Holstein cows with multiple PNSTs. A single SNP on chromosome 27 reached genome-wide significance.

Conclusions

Gross and histological characteristics of bovine PNSTs are comparable to PNSTs in humans (schwannomatosis). Danish Holsteins are genetically disposed to develop PNSTs but the examined materials are insufficient to allow determination of the mode of inheritance.     

Fecal ammonia, urea, volatile fatty acid and lactate levels in dairy cows and their pathophysiological significance during diarrhea

Normal fecal samples were taken from lactating cows fed either a total mixed ration (TMR; n = 30) or pasture‐based diet (20) and from dry cows fed mainly on hay (15). Diarrheic fecal samples (n = 51) were collected from 21 sick dairy cows. Fecal analyses of ammonia, urea, lactate and volatile fatty acid (VFA) levels were used to evaluate colonic fermentation. Most normal feces had reasonably neutral pH, however, alkaline feces were observed in diarrheic cows. Although fecal lactate is higher in cows on grazing pasture, lactate levels were generally lower in the cows in the present study. Fecal VFA levels were higher in lactating cows than in dry cows. Elevated fecal urea was observed in diarrheic cows, however, many fecal samples in normal and diarrheic cows contained no urea. Fecal VFA levels in diarrheic cows were lower than in normal lactating cows, but were approximately equivalent to those in dry cows. Grazing or dry cows showed higher acetate and lower n‐butyrate proportions compared with TMR‐fed or diarrheic cows. Higher proportions of branched chain VFAs were observed in diarrheic cows, and the lowest level was observed in grazing cows. The present results indicate that intracolonic nitrogen equilibrium and proteolytic fermentation are altered by diarrheic status.     

Rumination behavior of grazing dairy cows in response to restricted time at pasture

The short-term adaptations of cattle behavior to time restrictions at pasture are poorly understood. This study explored the diurnal rumination pattern of dairy cows in response to restrictions to time at pasture. Six groups of eight Holstein–Friesian cows (470 ± 47 kg, 35 ± 9 days in milk) were strip-grazed on a perennial ryegrass (Lolium perenne L.) pasture over 21 days (2 groups per treatment) for either 4 h after each milking (2 × 4), one period of 8 h between milkings (1 × 8), or 24 h excluding milking times (control, CTL). All cows were equipped with HR Tag™ rumination collars which recorded chewing activity and regurgitation of digesta boluses during rumination. Cows in 1 × 8 reduced daily rumination time by 36% compared with cows in 2 × 4 and CTL (304, 402 and 423 SED 26.3 min, respectively). There were no differences in the average intervals between regurgitation of digesta boluses (48.9 ± 0.96 s) and average interval between chewing actions was also similar (0.7 ± 0.02 s) between treatments. Treatment affected the diurnal rumination pattern. There was little rumination during the time at pasture for the restricted cows (1 × 8 and 2 × 4), whereas the CTL cows ruminated for almost a third of the time between the am and pm milking. In all treatments, cows ruminated the longest during the night. These results suggest grazing dairy cows modulate their time for rumination to compensate for a reduction in available grazing time. This behavioral study contributes to the understanding of changes in rumination behavior and associated effects in grazing dairy cattle in response to hunger.     

Effect of yeast culture on milk production and metabolic and reproductive performance of early lactation dairy cows

Background

The main objective of this study was to estimate the effect of supplementation with Saccaromyces cerevisiae (SC) (Yea-Sacc^® 1026) on milk production, metabolic parameters and the resumption of ovarian activity in early lactation dairy cows.

Methods

The experiment was conducted during 2005/2006 in a commercial tied-house farm with an average of 200 milking Estonian Holstein Friesian cows. The late pregnant multiparous cows (n = 46) were randomly divided into two groups; one group received 10 g yeast culture from two weeks before to 14 weeks after calving. The groups were fed a total mixed ration with silages and concentrates. Milk recording data and blood samples for plasma metabolites were taken. Resumption of luteal activity was determined using milk progesterone (P₄) measurements. Uterine bacteriology and ovarian ultrasonography (US) were performed and body condition scores (BCS) and clinical disease occurrences were recorded. For analysis, the statistical software Stata 9.2 and R were used to compute Cox proportional hazard and linear mixed models.

Results

The average milk production per cow did not differ between the groups (32.7 ± 6.4 vs 30.7 ± 5.3 kg/day in the SC and control groups respectively), but the production of milk fat (P < 0.001) and milk protein (P < 0.001) were higher in the SC group. There was no effect of treatment on BCS. The analysis of energy-related metabolites in early lactation showed no significant differences between the groups. In both groups higher levels of β-hydroxybutyrate (BHB) appeared from days 14 to 28 after parturition and the concentration of non-esterfied fatty acid (NEFA) was higher from days 1–7 post partum (PP). According to US and P₄ results, all cows in both groups ovulated during the experimental period. The resumption of ovarian activity (first ovulations) and time required for elimination of bacteria from the uterus did not differ between the groups.

Conclusion

Supplementation with SC had an effect on milk protein and fat production, but did not influence the milk yield. No effects on PP metabolic status, bacterial elimination from the uterus nor the resumption of ovarian activity were found.     

Oat silage for grazing dairy cows in small-scale dairy systems in the highlands of central Mexico

The objective was to evaluate the provision of oat silage (Avena sativa) to supplement grazing dairy cows on pastures of perennial ryegrass (Lolium perenne), festulolium (Lolium multiflorum × Festuca pratense) and white clover (Trifolium repens) during the dry season when pasture growth is limited. The experimental design was a 3 × 3 Latin square replicated three times, with nine milking Holstein cows (mean live weight 496.2 ± 33.6 kg and daily milk yield 14.8 ± 2.8 kg cow^?1) under on-farm participatory rural research. Experimental periods were 14 d. Simulated grazing samples of pasture herbage were analysed for chemical composition, sward height recorded and net herbage accumulation determined from exclusion cages. Treatments were the inclusion of oat silage at T0 = 0 kg DM cow^?1 d^?1 of oat silage, T3 = 3 kg DM cow^?1 d^?1 of oat silage, and T6 = 6 kg DM cow^?1 d^?1 of oat silage, plus 5.0 kg fresh weight commercial concentrate and 9 h of continuous grazing. Animal variables were milk yield and composition, live weight and body condition score. Feeding costs were calculated. Mean milk yield was 18.9 ± 0.27 kg cow^?1 d^?1 with no differences in animal variables (p > 0.05), but feeding costs per kilogram milk increased 25% for T3 and 50% for T6. Oat silage supplementation is only viable under difficult grazing conditions.     

The effect of Lameness before and during the breeding season on fertility in 10 pasture-based Irish dairy herds

Background

The effects of lameness on fertility have been documented frequently but few data are available from seasonally breeding, pasture-based herds (such as those used in Ireland) where cows are housed during the winter months but managed at pasture for the remainder of the year. This study determined the prevalence of lameness in a group of 786 cows in 10 pasture-based Irish dairy herds before, during and after the breeding season and assessed the relationship between lameness and the reproductive performance in these herds through serial locomotion scoring during the grazing period.

Results

Lameness prevalences of 11.6 % before, 14.6 % during and 11.6 % after the breeding season were found and these compared favourably to results from housed cattle and are similar to other studies carried out in grazing herds. A Cox proportional hazards model with locomotion score as time varying covariate was used. After controlling for the effect of farm, month of calving, body condition score at calving, body condition score loss after calving and economic breeding index, cows identified as lame during the study were less likely to become pregnant. Cows lame before the earliest serve date but no longer lame during the breeding season, cows becoming lame after the earliest serve date and cows identified lame both before and after this date were respectively 12 %, 35 % and 38 % less likely to become pregnant compared to cows never observed lame during the study. However, these findings were only significant for cows becoming lame after the earliest serve date and cows lame both before and after the start of breeding.

Conclusions

This study found that the reproductive efficiency was significantly (p < 0.05) lower in cows becoming lame during the breeding season and cows lame before and during the breeding season compared to non-lame cows. Cows no longer lame during the breeding season had a lower Submission Rate to first serve within 3 weeks of earliest serve date. However, the Pregnancy Rate was not significantly (p > 0.05) lower in these animals compared to cows never diagnosed as lame. In addition to lameness status, nutritional status and genetics were found to influence the reproductive performance in pasture-based Irish dairy herds.     

Screening for bovine leukocyte adhesion deficiency,deficiency of uridine monophosphate synthase,complex vertebral malformation,bovine citrullinaemia,and factor XI deficiency in Holstein cows reared in Turkey

Background

Bovine leukocyte adhesion deficiency (BLAD), deficiency of uridine monophosphate synthase (DUMPS), complex vertebral malformation (CVM), bovine citrullinaemia (BC) and factor XI deficiency (FXID) are autosomal recessive hereditary disorders, which have had significant economic impact on dairy cattle breeding worldwide. In this study, 350 Holstein cows reared in Turkey were screened for BLAD, DUMPS, CVM, BC and FXID genotypes to obtain an indication on the importance of these defects in Turkish Holsteins.

Methods

Genomic DNA was obtained from blood and the amplicons of BLAD, DUMPS, CVM, BC and FXID were obtained by using PCR. PCR products were digested with TaqI, AvaI and AvaII restriction enzymes for BLAD, DUMPS, and BC, respectively. These digested products and PCR product of FXID were analyzed by agarose gel electrophoresis stained with ethidium bromide. CVM genotypes were detected by DNA sequencing. Additionally, all genotypes were confirmed by DNA sequencing to determine whether there was a mutant allele or not.

Results

Fourteen BLAD, twelve CVM and four FXID carriers were found among the 350 Holstein cows examined, while carriers of DUMPS and BC were not detected. The mutant allele frequencies were calculated as 0.02, 0.017, and 0.006 for BLAD, CVM and FXID, respectively with corresponding carrier prevalence of 4.0% (BLAD), 3.4% (CVM) and 1.2% (FXID).

Conclusion

This study demonstrates that carriers of BLAD, CVM and FXID are present in the Turkish Holstein population, although at a low frequency. The actual number of clinical cases is unknown, but sporadic cases may appear. As artificial insemination is widely used in dairy cattle breeding, carriers of BLAD, CVM and FXID are likely present within the population of breeding sires. It is recommended to screen breeding sires for these defective genes in order to avoid an unwanted spread within the population.     

A pilot study to determine the production and health benefits of milking visibly lame cows twice daily compared with three times daily

A randomized clinical trial was conducted on lame cows to study the effect of milking frequency on milk production, lameness prevalence, and body condition score (BCS). At the beginning of the study, the entire herd of lactating Holstein dairy cows was visual locomotion scored (VLS) by 2 trained veterinarians. Lame cows (VLS > 2) were eligible for the study. The initial study population consisted of 270 cows randomly allocated to the three-times-daily milking frequency group (MFG) and 230 cows randomly allocated to the twice-daily MFG. Milking frequencies did not significantly affect average milk production. Cows in the twice-daily MFG had a significant increase in BCS, however, compared with cows in the three-times-daily MFG (P-value < 0.001). In addition, the probability of lameness in cows in the three-times-daily MFG was 36% higher than for cows in the twice-daily milking routine (P-value = 0.006).