Loss In Dairy Cows Research Articles

Effects of dehydrated lucerne and soya bean meal on milk production and composition, nutrient digestion, and methane and nitrogen losses in dairy cows receiving two different forages

Dehydrated lucerne is used as a protein source in dairy cow rations, but little is known about the effects of lucerne on greenhouse gas production by animals. Eight Holstein dairy cows (average weight: 582 kg) were used in a replicated 4×4 Latin square design. They received diets based on either maize silage (M) or grass silage (G) (45% of diet on dry matter (DM) basis), with either soya bean meal (15% of diet DM) completed with beet pulp (15% of diet DM) (SP) or dehydrated lucerne (L) (30% of diet DM) as protein sources; MSP, ML, GSP and GL diets were calculated to meet energy requirements for milk production by dairy cows and degradable protein for rumen microbes. Dry matter intake (DMI) did not differ among diets (18.0 kg/day DMI); milk production was higher with SP diets than with L diets (26.0 v. 24.1 kg/day), but milk production did not vary with forage type. Milk fatty-acid (FA) composition was modified by both forage and protein sources: L and G diets resulted in less saturated FA, less linoleic acid, more trans-monounsaturated FA, and more linolenic acid than SP and M diets, respectively. Enteric methane (CH4) production, measured by the SF6 tracer method, was higher for G diets than for M diets, but did not differ with protein source. The same effects were observed when CH4 was expressed per kg milk. Minor effects of diets on rumen fermentation pattern were observed. Manure CH4 emissions estimated from faecal organic matter were negatively related to diet digestibility and were thus higher for L than SP diets, and higher for M than G diets; the resulting difference in total CH4 production was small. Owing to diet formulation constraints, N intake was higher for SP than for L diets; interaction between forage type and protein source was significant for N intake. The same statistical effects were found for N in milk. Faecal and urinary N losses were determined from total faeces and urine collection. Faecal N output was lower for M than for G diets but did not differ between protein sources. Urinary N output did not differ between forage types, but was lower for cows fed L diets than for cows fed SP diets, potentially resulting in lower ammonia emissions with L diets. Replacing soya bean meal plus beet pulp with dehydrated lucerne did not change CH4 production, but resulted in more N in faeces and less N in urine.

Observed and expected combined effects of clinical mastitis and low body condition on pregnancy loss in dairy cows

The objective was to compare the observed and expected combined effects of clinical mastitis before timed artificial insemination (TAI) and low body condition at 70 d postpartum (dpp) on pregnancy loss in dairy cows. Cows were examined for pregnancy by ultrasonographic examination 28–32 d after TAI; the presence of an embryo with a heartbeat was the criterion used to determine pregnancy. Cows diagnosed pregnant were re-examined by transrectal palpation of the uterus and its contents 28 d later to confirm pregnancy status and to identify pregnancy loss. Eighty-eight (17%) of 512 cows were diagnosed with pregnancy loss. Cows affected with clinical mastitis before insemination and a body condition score (BCS) ≤ 2.75 at 70 dpp were 2.03 times more likely to experience pregnancy loss, compared to cows without clinical mastitis and with a BCS > 2.75 (RR = 2.03; 95% CI = 1.15, 3.60; P = 0.01). This observed combined effect for pregnancy loss (RR = 2.03) was higher than the expected combined effect based on adding (RR = 1.39) or multiplying (RR = 1.42) absolute independent excesses due to clinical mastitis or low body condition.

Association between anti-F. hepatica antibody levels in milk and production losses in dairy cows

This study was conducted to determine: (1) the associations between anti-Fasciola hepatica antibody levels in milk and some productive and reproductive parameters in dairy cattle, and (2) the threshold antibody level associated with loss of productivity, at both herd and individual level. Anti-F. hepatica antibodies were analysed by MM3-SERO ELISA in milk samples from the bulk tanks of 490 dairy farms and from 686 lactating cows. The results of general linear model analysis revealed a significant (P<0.05) negative association between the F. hepatica infection status at herd level, determined by analysis of specific antibodies in bulk tank milk, and the average herd milk production. Highly positive herds (MM3-SERO ELISA result>0.405) produced an average of 1.5kg milk/cow per day less than the negative herds. At cow-level, the mixed model analysis also revealed a significant (P<0.05) association between anti-F. hepatica antibody levels and milk yield. A significant (P<0.05) average reduction of 2kg milk/day was observed in cows with highly positive ELISA results (>0.762) in relation to cows with negative results. The results of the study led us to conclude that MM3-SERO ELISA is a powerful tool that can be successfully applied, if appropriate “economic thresholds” are established, to identify herds and cows suffering from milk production losses associated with natural infection by F. hepatica.

Effect of dietary concentrate on rumen fermentation, digestibility, and nitrogen losses in dairy cows

The objective of this experiment was to investigate the effect of level of dietary concentrate on rumen fermentation, digestibility, and N losses in lactating dairy cows. The experiment was a replicated 3×3 Latin square design with 6 cows and 16-d adaptation periods. Ruminal contents were exchanged between cows at the beginning of each adaptation period. Data for 2 of the diets tested in this experiment are presented here. The diets contained (dry matter basis): 52% (LowC; control) and 72% (HighC) concentrate feeds. Crude protein contents of the diets were 16.5 and 16.4%, respectively. The HighC diet decreased ruminal pH and ammonia concentration and increased propionate concentration compared with LowC. Acetate:propionate ratio was greater for LowC than for HighC. Rumen methane production and microbial protein synthesis were unaffected by diet. Dry matter intake was similar among diets, but milk yield was increased by HighC compared with LowC (36.0 and 33.2kg/d, respectively). Milk fat percentage and yield and total-tract apparent NDF digestibility were decreased by HighC compared with LowC. More ruminal ammonia N was transferred into milk protein with HighC than with LowC. Urinary N excretion, plasma urea N, and milk urea N concentration were not affected by diet. The ammonia emitting potential of manure was similar between LowC and HighC diets. Increased concentrate proportion in the diet of dairy cows resulted in reduced ruminal ammonia concentration and enhanced ammonia utilization for milk protein synthesis. These effects, however, did not result in reduced urinary N losses and only marginally improved milk N efficiency. Increasing dietary concentrate was not a successful strategy to mitigate enteric methane production and ammonia emissions from manure.

116 EFFECTS OF EARLY PREGNANCY DIAGNOSIS USING ULTRASONOGRAPHY ON THE SUBSEQUENT EMBRYO AND FETAL LOSS IN DAIRY COWS

Under on-farm condition, pregnancy diagnosis can be rapidly and accurately diagnosed using ultrasound. However, the risk of the incidence of embryo and fetal loss following early pregnancy diagnosis has not been fully determined. This study assessed, using ultrasonography, the incidence of embryo and fetal loss in dairy cows following early pregnancy diagnosis after artificial insemination. A positive pregnancy was the recognition of the vesicle, embryo, or fetus by ultrasonography (Sonoace 600 with 5.0- or 7.5-MHz linear array transducer; Medison Co., Ltd., Seoul, Korea). Pregnancies (n = 702) were divided into three groups according to the number of days pregnant diagnosed: early A group (27 to 40 days, n = 143), early B group (41 to 50 days, n = 172), or standard group (51 to 70 days, n = 387). Following a positive pregnancy diagnosis, embryo or fetal loss included all cows with observed abortions and also cows found open after the positive pregnancy diagnosis. Data were analyzed by chi-square test or Fisher's exact test using an SAS program (SAS Institute, Inc., Cary, NC, USA). The incidence rate of embryo or fetal loss within 7 days after pregnancy diagnosis was 1.4, 0.6, and 0.3% for the early A, early B, and standard groups, respectively (P &gt; 0.05). The incidence rate of the embryo or fetal loss during 8 to 30 days after pregnancy diagnosis was not different (P &gt; 0.05) among the early A (0%), early B (1.2%), and standard groups (1.0%). Furthermore, the cumulative incidence rate of the embryo or fetal loss before calving was not different (P &gt; 0.05) among the early A (9.8%), early B (9.3%), and standard groups (5.9%). In conclusion, early pregnancy diagnosis using ultrasonography does not significantly increase the risk of embryo and fetal loss in dairy cows. This work was supported by the research grant of the Chungbuk National University in 2007.

Pregnancy loss in dairy cows: the contributing factors, the effects on reproductive performance and the economic impact

This study investigated the effects of the herd, cow parity, the insemination protocol and season on the incidence of pregnancy loss (PL) in dairy herds. Furthermore, we determined the downstream effects of PL on reproductive performance and its economic impact. The overall incidence rate of PL was 6.9% in 1,001 pregnant cows and its incidence peaked (p < 0.01) during the second trimester of gestation. GLIMMIX analysis revealed that cow parity was the important risk factor for the PL. The odds ratio showed that the likelihood of PL in cows with parities of 1 or 2 was decreased by 0.6 or 0.5 fold compared to the cows with a parity of 3 or higher. Following PL, the mean rate of endometritis was 23.2% and endometritis was more common (p < 0.05) when PL occurred during the third trimester than during the first and second trimesters. The mean culling rate was 46.4% and this did not differ with the period of PL. The overall mean intervals from PL to the first service and conception were 63.4 and 101.8 days, respectively. The mean interval from PL to first service was longer (p < 0.01) for cows with PL during the third trimester than for the cows with PL during the first and second trimesters. The economic loss resulting from each PL was estimated at approximately $2,333, and this was largely due to an extended calving interval and increased culling. These results suggest that cow parity affects the incidence of PL, which extends calving interval and causes severe economic loss of dairy herds.

The effect of subclinical bovine herpesvirus 1 infection on fertility of cows and heifers

The aim of this study was to determine the serological prevalence of bovine herpesvirus 1 (BHV-1), and describe whether natural subclinical infections will lead to fertility losses in dairy cows and heifers in Burdur, Turkey. BHV-1 prevalence was 11.94% (201/24) and 14.60% (89/13) in cows and heifers respectively. Conception rate (CR) was higher in BHV-1 serologically negative cows (38.98%) than BHV-1 positive cows (33.33%) but the difference was statistically insignificant (P>0.05). However, CR was higher (P>0.05) in BHV-1 serologically positive heifers (84.61%) than BHV-1 negative heifers (56.57%). Average open days period (OD) of BHV-1 serologically positive cows (99.3 ± 16 d) was different from BHV-1 negative cows (82.0 ± 3.8 d) (P<0.05). Average for the first service (FSA) of BHV-1 serologically positive heifers (18.01 ± 1.1 mo) did not differ from BHV-1 negative heifers (18.0 ± 0.3 mo) (P>0.05). Results of the current study showed that BHV-1 serologically positive cows have required for successful conception about 17 days more than negative cows.

Extent, pattern and factors associated with late embryonic loss in dairy cows

Intensive genetic selection for increased milk production, coupled with increased dry matter intakes has led to significant improvements in cow milk yield, however, this increase in milk output has been accompanied by a decline in cow fertility. It has been suggested that there is a higher increment of late embryonic loss in high-yielding than in moderate yielding cows or in heifers. The objectives of this study were to establish the extent and pattern of embryonic loss, from days 28 to 84 of gestation, and to examine possible relationships between cow milk yield, cow genetic merit, parity, calving to insemination interval and embryonic loss in dairy cows managed mainly under pasture-based milk production systems. Multiparous dairy cows ( n=1046) located on 8 farms and nulliparous dairy heifers ( n=162) located on five of these farms were used in this study. The extent and timing of embryonic loss was measured by ultrasound scanning of the cows and heifers at 14-day intervals between days 28 and 84 of gestation. Positive diagnosis of pregnancy was based on the presence of an embryo or foetus with a visible heartbeat and, at the later scans, visible movement, whose size was compatible with stage of gestation and also on the presence of clear amniotic fluid of the cows and heifers presented as presumed pregnant on day 28 after insemination, 67 and 81%, respectively had a viable embryo. The subsequent embryonic loss rate between days 28 and 84 of gestation was similar ( P>0.05) for cows (7.2%) and heifers (6.1%) and the pattern of loss over this period was also similar ( P>0.05) for cows and heifers. There was no significant association ( P>0.05) between level of milk production or milk energy output measured to day 120 of lactation and embryonic loss rate. Similarly, there was no significant relationship ( P>0.05) between % milk fat, % milk protein and % milk lactose and embryonic loss rate. The extent and pattern of embryonic loss were not related ( P>0.05) to either cow or to cow sire genetic merit. There was no significant ( P>0.05) relationship between the calving to first service interval and embryonic loss. The extent of embryonic loss was greater ( P<0.05) in cows that lost body condition between days 28 and 56 of gestation compared with cows than either maintained or improved in body condition.

Reproductive Loss in High-Producing Dairy Cattle: Where Will It End?

The dairy industry in the United States has changed dramatically in the last decade. Milk production per cow has increased steadily because of a combination of improved management, better nutrition, and intense genetic selection. Dairy farms are larger, and nearly 30% of the dairy cows in the United States are on farms with 500 or more cows. The shift toward more productive cows and larger herds is associated with a decrease in reproductive efficiency. Cows with the greatest milk production have the highest incidence of infertility, but epidemiological studies suggest that, in addition to milk production, other factors are probably decreasing reproductive efficiency in our dairy herds. The reproductive physiology of dairy cows has changed over the past 50 yr, and physiological adaptations to high milk production may explain part of the reproductive decline. Critical areas for new research include control of the estrous cycle, metabolic effects of lactation on reproduction, mechanisms linking disease to reproduction, and early embryonic mortality. Solving reproductive loss in dairy cows will not be easy because only a small number of research groups study reproduction in postpartum dairy cows. Therefore, the present research base will need to be expanded. For this to occur, research funding must be increased above its current level and a renewed emphasis must be placed on solving the emerging crisis of infertility in dairy cows.

Changes in composition and energy content of liveweight loss in dairy cows with time after parturition

A research was carried out to determine the amount, energy value, and composition of body tissue mobilized in dairy cows in their first 8 weeks of lactation. Mobilization was calculated from the energy balance and change in empty body weight per week. Mobilization was highest in the first week after parturition and decreased during the progress of lactation. The composition in terms of fat and protein per kg mobilized tissue was not constant during the first weeks after parturition. Protein mobilization decreased rapidly and fat mobilization more slowly, resulting in an increasing fat-to-protein ratio within the mobilized tissue. For protein, mobilization changed to retention in week 5, while fat mobilization still continued. Calculations showed that cows can produce as much as between 120 and 550 kg of milk from body reserves on the basis of energy (average 324 kg). Maximum mobilization in 8 weeks amounted to 41.6 kg empty body weight, 30.9 kg fat and 4.6 kg protein.

The usefulness of the computerized medical records of one practice for research into pregnancy loss in dairy cows

The use of routinely collected data for epidemiological research has been advocated to reduce the cost of field research. The disadvantage of such an approach is the lack of control over the collection and quality of the data. This study was undertaken to describe the quality of practice-generated computerized medical records and to assess their usefulness as a source of data for research. In particular, this study evaluated the quality of the medical records generated by one software program for research into pregnancy loss in dairy cows. The records of approximately 4000 cows in 70 herds in one private dairy practice were analyzed. Various methods were used to assess data quality. The task of preparing the medical records for analysis was complex. However, the programs written for this study could be adapted for use elsewhere allowing the generation of similar data-sets from other practices. The quality of the data available from these medical records was acceptable. More information is needed to set standards for quality in data-sets such as this. The observed tendency of cows with complete data to have worse reproductive performance has divergent implications for practising veterinarians. More work is needed to refine this association.

Serum zinc and copper concentrations in relation to spontaneous abortion in cows: implications for human fetal loss.

The purpose of this study was to investigate the effect of the status of dietary zinc and serum zinc and copper concentrations on the risk of fetal loss in 570 cows. three herds received no supplements (herds 1, 3, 4), while cows in herd 2 received supplements of either 7 g zinc week-1 (n = 118), as zinc methionine, or a control diet containing methionine (n = 128). Serum zinc, copper and metallothionein concentrations were determined once a month throughout gestation. Logistic regression and survival analysis were used to examine for associations between risk of fetal loss and serum zinc, copper, copper:zinc, or metallothionein concentrations, supplement level, and maternal age at conception. The risk of fetal loss increased when both serum zinc decreased and copper concentrations increased (P < 0.0001; relative risk = 10.28, 95% confidence intervals = 4.69, 22.5). The attributable risk, for a decline in the zinc concentration by 10 mumol l-1 and an increase in the copper concentration by 5 mumol l-1 was 90.27%. Methionine-supplemented cows had a higher risk of fetal loss compared with zinc-methionine-supplemented cows (one-tailed P = 0.0375; relative risk = 2.98). Cows in herds 1, 3 and 4 had a higher risk for abortion than did zinc-methionine-supplemented cows in herd 2 (relative risk = 26.27, 95% confidence intervals = 2.31, 299.38; relative risk = 40.87, 95% confidence intervals = 3.50, 458.43; relative risk = 41.53, 95% confidence intervals = 3.77, 457.02, respectively). Our results suggest that inflammation and zinc nutriture may play an important role in fetal loss in dairy cows.

Influence of dry matter intake on faecal phosphorus losses in dairy cows fed rations low in phosphorus

ZusammenfassungEinfluß der Futteraufnahme auf die Phosphor‐Verluste im Kot von Milchkühen bei Fütterung von Rationen mil niedrigem PhosphorgehaltAn zweimal fünf Milchkühe gleicher mittlerer Lebendmasse, die sich jedoch in der Höhe ihrer Milchleistung unterschieden, wurden der Leistung entsprechend pro Kuh und Tag 16,9 kg (Gruppe I) und 10,9 kg (Gruppe II) Trockenmasse einer Ration gleicher Zusammensetzung gefüttert. Die tägliche Phosphor‐Aufnahme je Kuh betrug 37,0 g in Gruppe I und 21,5 g in Gruppe II. Zwischen beiden Gruppen zeigten sich keine Unterschiede in den Verdaulichkeiten der Rohnährstoffe und im Gehalt an anorganischem Phosphat im Blutserum.In der neuntägigen Sammelperiode ergab sich für die Gruppen I und II mit – 1,6 g und – 0,8 g eine nicht signifikant von 0 unterschiedliche “P‐Bilanz”. Die Ausscheidung im Kot betrug für beide Gruppen 1,2 g P je kg aufgenommener Trockenmasse. Aus den Ergebnissen wird geschlossen, daß die unvermeidlichen P‐Verluste im Kot von der Höhe der Trockensubstanzaufnahme abhängen und folglich in der faktoriellen Bedarfsableitung darauf bezogen werden sollten.

Assessment of the Quality of Practice-Generated Computerized Medical Records as a Data Source For Research Into Pregnancy Loss in Dairy Cows

This paper discusses the suitability of medical records as a source of data for research into the problem of pregnancy loss in dairy cows. The process of converting the computerized veterinary practice records into analyzable data is described. Various measures of data quality are discussed including the percent of missing, incorrect and outlier values in the final data set. Finally, descriptive statistics are calculated to demonstrate the similarity between the population of dairy cows described by the medical records and the target population of commercial dairy cows. This paper demonstrates that the positive aspects of practice-generated computerized medical records (volume of data, similarity to the target population) compensate for the disadvantages of poor case definition and missing data. The analysis of these data to investigate pregnancy loss in dairy cattle is currently under way and will be reported elsewhere.

Considerations for use of descriptive epidemiology to investigate fetal loss in dairy cows

Summary Various descriptive approaches were taken in a prospective investigation to characterize fetal loss in cows on a California dairy. The methods and observations were offered for consideration by practitioners engaged in dairy herd health medicine. For 4,732 pregnancies followed from 2,163 cows in a 6.5 year period, the respective proportions (percentage) of cows aborting (1 – cumulative proportion not aborting by 260 days) and abortion densities (abortions per 10,000 cow-days-at-risk) were 10.63 and 6.29 for all fetal deaths, 9.36 and 5.49 for deaths resulting in fetal expulsion, and 1.39 and 0.80 for deaths resulting in mummification. The greatest risk of fetal death (119 deaths/10,000 fetuses/d) was observed between 98 and 105 days of gestation, and median age at fetal death ranged from 99.0 to 105.5 days. Abortion density for fetal deaths resulting in mummification for cows conceiving during September (1.61/10,000 fetuses/d) and October (1.63/10,000 fetuses/d) was tenfold greater than that for cows conceiving in February (0.16/10,000 fetuses/d) and was twice that of the overall rate (0.84/10,000 fetuses/d). For cohorts of nonculled cows, abortion rate increased after 5 years of age, after 5 pregnancies, or after 4 calvings. For cows with at least one previous abortion, the proportion aborting (14.50%) was higher than that for cows without a previous abortion (12.14%). For a given gravidity, abortion rate was higher among cows that had experienced a previous abortion, compared with those that had not. These methods and observations may help provide a logical foundation on which to base clinical hypotheses regarding causes of abortion, and they may offer insight into pitfalls of bias and confounding to be anticipated.