Death of pregnant heifers at a dairy farm due to fatty liver disease

Fatty liver disease usually occurs in periparturient dairy cows. However, this case study describes the occurrence of the disease in maiden heifers on a dairy farm during late gestation. It resulted in the death of 5 heifers (21-25 months of age) within 31 days after turning them out to grass. The diagnosis was confirmed by blood testing and gross pathology findings. Housing the animals and providing them with good quality grass silage prevented further clinical cases.     

The effect of concentrate level and concentrate composition on the performance of growing dairy heifers reared and finished for beef production

Abstract

The objectives of the study with growing dairy heifers were to determine the effects on animal performance of (1) concentrate level and (2) the concentrate composition in the grass silage-based diet. Animals (30 heifers) were randomly assigned to three feeding treatments: (1) low level (1.75 kg dry matter (DM)/d) of rolled barley (LB); (2) low level (1.75 kg DM/d) of commercial pelleted concentrate (LC); and (3) medium level (3.5 kg DM/d) of commercial pelleted concentrate (MC). All animals were also offered grass silage and hay. The commercial concentrate contained more crude protein than barley grain (135 g/kg DM vs. 205 g/kg DM). The data were analysed using analysis of variance and differences between the treatments were tested by orthogonal contrasts: LC vs. MC and LB vs. LC. The growth of the heifers increased and carcass conformation improved with increasing concentrate level. Commercial concentrate did not improve animal performance compared with barley grain.     

Comparison of the German and the Dutch protein evaluation system in dairy nutrition when applied to different rations with graded protein levels.

The Dutch (DVE) and the German (nXP) protein evaluation system were compared using data from four specially designed dairy feeding trials. The criterion for comparison was the divergence between predicted and observed milk protein yield with the respective protein evaluation system. Different forages were fed in each series of experiments, namely red clover/meadow grass, meadow grass, grass silage and maize silage, respectively. To achieve a diversified database, protein was supplied at 2 or 3 different levels in each experiment. Across all measured data, the two protein evaluation systems resulted sometimes in considerable differences between predicted and observed protein yield. The observed yield was overestimated by 223 g per cow and day with the DVE system and by 144 g per cow and day with the nXP system. The magnitude of the bias varied depending on the type of ration fed. In experiments with fresh forage the difference between predicted and observed milk protein yield was far greater with the DVE system than that calculated with the nXP system (difference 322 g vs. 162 g), whereas after feeding grass silage the differences between the two protein evaluation systems were small (194 g vs. 182 g). In experiments with maize silage the predicted value was close to the observed value both with the DVE and the nXP system (difference 48 g vs. 80 g).     

Grass silage intake, rumen and blood variables, ultrasonic and body measurements, feeding behavior, and activity in pregnant beef heifers differing in phenotypic residual feed intake

The objectives of this study were to quantify the phenotypic variation in residual feed intake (RFI) in pregnant beef heifers offered a grass silage diet and to characterize their productivity. Seventy-three pregnant (mean gestation d 198, SD = 27 d) Simmental and Simmental × Holstein-Friesian heifers (mean initial BW 548, SD = 47.5 kg) were offered grass silage ad libitum. Heifer DMI, BW, BCS, skeletal measurements, ultrasonic fat and muscle depth, visual muscularity score, rumen fermentation, total tract digestibility, blood metabolite and hematology variables, feeding, and activity behavior were measured during an 84-d feed intake study. After parturition calf birth weight, calving difficulty, cow serum IgG, hematology variables, and calf humoral immune status were measured. In a subset of cows (n = 28), DMI, milk yield and various body composition variables were also measured approximately 3 wk postpartum. Phenotypic RFI was calculated for each animal as the difference between actual DMI and expected DMI. Expected DMI was computed for each animal by regressing average daily DMI on conceptus-adjusted mean BW(0.75) and conceptus-adjusted ADG over an 84-d period. Within breed, heifers were ranked by RFI into low (efficient), medium, and high (inefficient) groups by dividing them into thirds. Heifers with high RFI had 8.8 and 17.1% greater (P < 0.001) DMI than medium and low RFI groups, respectively. The RFI groups did not differ in ADG or BW (P > 0.05). Residual feed intake was positively correlated with DMI (r = 0.85) but not with feed conversion ratio, ADG, or BW. The RFI groups did not differ (P > 0.05) in skeletal size, BCS, ultrasonic fat depth, total tract digestibility, calf birth weight, calving difficulty, serum IgG concentrations, or milk yield. Visual muscularity scores, initial test and postpartum ultrasonic muscle depth were negatively correlated with RFI (P < 0.05). Including mean ultrasonic muscle depth into the base RFI regression model increased its R(2) (0.29 to 0.38). Pearson rank correlation between RFI and muscle-adjusted RFI was 0.93. The results show that efficient RFI heifers consumed less feed without any compromise in growth, body composition, or maternal traits measured.     

Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 1. In vitro and in vivo studies of nitrogen utilization

Two experiments were carried out to determine the effects of feeding grass silages differing in their water-soluble carbohydrate content, with or without red clover silage, on the efficiency of nutrient use. High-sugar grass, control grass, and red clover were ensiled in laboratory silos for use in an in vitro experiment (Exp. 1). For an in vivo experiment (Exp. 2), the same forage types were baled and ensiled. All silages were well preserved; within experiments the grass silages had similar composition, except for greater (P < 0.05) water-soluble carbohydrate concentrations in the high-sugar than the control grass silage. In Exp. 1, high-sugar grass, control grass, and red clover silages were fed alone or as mixtures (30:70, 50:50, or 70:30 on a DM basis, respectively) of each grass with the red clover silage to a simulated rumen culture system. There were no significant differences in microbial N flow or efficiency of microbial protein synthesis between individual forages. However, the corresponding values for the 70:30 ratio of high-sugar grass:red clover silage were greater (P < 0.05) than for the red clover silage. The value for the efficiency of N use (g of microbial N/g of feed N) was greater (0.86; P < 0.05) for high-sugar grass silage than the control grass silage. In addition, the high-sugar grass:red clover silage mixtures all gave greater (P < 0.05) values for the efficiency of N use than red clover silage alone; this difference was not achieved with the control grass mixture. Experiment 2 was an incomplete Latin square design conducted with 6 Here-ford x Friesian steers (163 +/- 5.9 kg of BW) with rumen and duodenal cannulas fed the following 5 silage diets: high-sugar grass silage; control grass silage; high-sugar grass and red clover silage (50:50 DM basis); control grass and red clover silage (50:50 DM basis); and red clover silage. Rumen NH3-N concentration was lowest (P < 0.05) with the high-sugar grass silage. Microbial N flows to the duodenum and efficiency of microbial protein synthesis were greater (P < 0.05) for steers fed the high-sugar grass silage than for control grass and red clover silages, and mixing red clover with grass silages increased (P < 0.05) these values compared with red clover silage alone. In both experiments, the efficiency of incorporation of silage N into microbial N was more than 20% greater (P < 0.05) for high-sugar grass than for control grass silage. These data suggest that grass silage with high-sugar content provides a forage-based strategy for balancing N and energy supply and improving the efficiency of use of grass silage N in the rumen.     

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass ( Anthoxanthum odoratum ). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis.     

Congenital joint laxity and dwarfism: A feed-associated congenital anomaly of beef calves in Canada

Five feeding trials were performed on three ranches to determine if a distinctive, recurring, congenital anomaly in beef calves was associated with feeding clover or grass silage without supplementation to pregnant cows overwinter. The anomaly, termed congenital joint laxity and dwarfism, was characterized at birth by generalized joint laxity, disproportionate dwarfism, and occasionally, superior brachygnathia. The anomaly had been documented for several consecutive years on these ranches and affected 2-46% of the calf crop.

Pregnant cows were divided randomly into feeding groups, and the number of abnormal calves in each group was tabulated. Supplementation of the overwinter grass/clover silage diet with hay (2.5-4.5 kg/head/day) and rolled barley (0.75-1.5 kg/head/day) eliminated the problem. Supplementation of grain, without hay, was not as effective. Varying the proportions of grass and clover in the silage, and the age of the silage, did not alter the teratogenic potency of silage. Vitamin D₃ supplementation did not reduce the risk of the condition. The definitive cause of congenital joint laxity and dwarfism was not determined.

     

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass (Anthoxanthum odoratum). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis. Activated partial thromboplastin time Haemoglobin Packed cell volume Prothrombin time Red cell count     

The effect of feeding grass silage in early pregnancy on claw health during first lactation

Two groups of eight Holstein-Friesian heifers were fed either a grass-silage-based diet (S) or one based on meadow hay supplemented with 1.8 kg/day barley concentrate mix (H) during cubicle housing as young stock (and in early pregnancy). Lameness and claw lesion development were monitored from approximately four weeks before until 20 weeks after first calving. No significant difference was found between S and H for claw conformation or horn growth and wear. Both groups showed net wear immediately after calving. The prevalence of poor locomotion and the extent of lesion development 20 weeks after calving (when they were highest) were significantly (P< 0.05) higher in S than H. It was concluded that feeding grass silage to young stock may deleteriously affect subsequent claw health and that this risk factor requires further study.     

Effects of high-sugar ryegrass silage and mixtures with red clover silage on ruminant digestion. 2. Lipids

The experiment investigated the digestion of lipids from different forage silages in beef steers. Six Hereford x Friesian steers prepared with rumen and duodenal cannulas were given ad libitum access to a high-sugar grass silage, control grass silage, red clover silage, or mixtures of the red clover and each of the grass silages (50:50, DM basis). The experiment was conducted as an incomplete 5 x 5 Latin square, with an additional randomly repeated sequence. Total fatty acid and C18:3n-3 concentrations were greater (P < 0.05) for the high-sugar grass silage than the control grass silage or the red clover silage. Dry matter and total fatty acid intake were less (P < 0.05) for steers fed the control grass silage than for steers fed the other diets. Duodenal flow of C18:3n-3 was greater (P < 0.05), and flows of C18:0 and total C18:1 trans were less (P < 0.05), for the red clover silage compared with the 2 grass silage diets, with the mixtures intermediate. These results were supported by a reduction (P < 0.05) in biohydrogenation of C18:3n-3 for the red clover silage, with the mixtures again being intermediate. Flows of total branched- and odd-chain fatty acids were greater (P < 0.05) for the high-sugar grass silage diet, possibly as a result of greater microbial flow, because these fatty acids are associated with bacterial lipid. Duodenal flows of the chlorophyll metabolite, phytanic acid, were greater (P < 0.05) for animals fed the high-sugar grass silage treatments compared with the other treatments. These results confirm the potential for modifying the fatty acid composition of ruminant products by feeding red clover silage.     

仙人掌果实对奶牛泌乳性能、氮利用及采食行为的影响

本研究评估了仙人掌果实与不同粗饲料结合对荷斯坦奶牛采食量、营养物质消化率、氮平衡、摄食行为和泌乳性能的影响。试验选择泌乳期为(72±11)d的8头奶牛,采用4×4拉丁试验设计,共4种试验日粮:T1组为75%青贮高粱组,T2组为75%象草组,T3组为37.5%青贮高粱+37.5%仙人掌果实,T4组为37.5%象草+37.5%仙人掌果实。结果:青贮高粱组干物质摄入量最高(P<0.05)。不同日粮组干物质、粗蛋白质、粗脂肪、非纤维碳水化合物和总可消化养分摄入量存在显著差异(P<0.05)。仙人掌果实组较青贮高粱和象草组日饮水量降低44.52%(P<0.05)。与象草组、象草+仙人掌果实组相比,青贮高粱组、青贮高粱+仙人掌果实组氮平衡降低59.71%和27.49%(P<0.05)。结论:奶牛日粮中以仙人掌果实与青贮高粱或象草的组合并没有改变荷斯坦奶牛的产奶量,但降低了营养物质和水分摄入量,同时提高了养分消化率。     

Tremorgenic syndrome in a cattle herd after feeding silage contaminated with A. clavatus

The clinical signs, pathological and laboratory findings of cattle suffering from a tremorgenic syndrome are described. Animals on a farm with a total of 22 cows, 18 heifers and 9 calves were fed mouldy grass and spent malt-grain silage. Five heifers were affected with muscular tremor, hyperexcitability and hypersensitivity. They were ataxic or in sternal recumbency, while their appetite remained normal. Haematology and blood chemistry in two heifers as well as cerebrospinal fluid from one sick animal were unremarkable. The pathological examination of one animal brought no macroscopic changes to light. Histological examination, however, revealed the degeneration of motor neurones in the midbrain, brain stem and spinal cord. Analysis of a silage sample provided evidence of the presence of Aspergillus clavatus, a mould capable of producing neurotoxic tremorgenic mycotoxins. Epidemiology, clinical findings, pathology and microbiological examination suggest that the five cattle were suffering from neuromycotoxicosis.     

Insulated, uninsulated and outdoor housing for replacement beef heifers on restricted grass silage-based diet in a cold environment

The present experiment studied whether replacement beef heifers, offered restricted amounts of a grass silage-based diet, can be overwintered in outdoor housing facilities in cold Nordic conditions (minimum temperature approximately − 35 °C). Twenty-one Hereford heifers, initial live weight (LW) 237 kg in Experiment 1 and 256 kg in Experiment 2, were selected for a two-year study. In both experiments, the treatments consisted of three winter housings which were Insulated pen (I), Uninsulated pen (U) and Outdoor area with a rain shelter (O). Grass silage supplemented with oats was offered restricted and the heifers received daily during winter on average 63 and 65 MJ metabolizable energy in Experiment 1 and 2, respectively. The live weight gain of the heifers in treatment U (795 g/d) was higher than in the other treatments (I; 760 and O; 747 g/d). No significant differences in the body condition score (scale from extremely thin, 0 to extremely fat, 5) were observed between the treatments. In Experiment 1, the serum concentrations of long-chain fatty acids were lower in the heifers in treatment I than in the heifers in the other treatments, probably due to increased lipolysis of the heifers in treatment I. In both experiments the serum concentrations of urea were lower and concentrations of total proteins higher in the animals in treatment I than in the other animals. No clear harmful effects, like muscle injuries, extraordinary stress or increased occurrence of diseases, could be observed in any of the treatments. The breeding season was 78 and 83 days in Experiment 1 and 2, respectively. The conception rate after natural breeding was 95% in both experiments. On the basis of the results, replacement beef heifers on a restricted feeding scheme can be overwintered outdoors in Nordic conditions without negative effects on animal performance. Nevertheless, the outdoor winter housing facilities must protect the animals from becoming wet and dirty and thus should be equipped with a rain shelter to provide a dry resting area with sufficient bedding material available.     

Evidence of residual feed intake reranking in crossbred replacement heifers

The objective of the study was to examine whether residual feed intake (RFI) reranking exists between 2 consecutive periods in replacement heifers fed the same diet. The study collected feed intake and BW data from 190 crossbred heifers over a 3-yr period (61 in 2007, 68 in 2008, and 61 in 2009) during the winter-spring season. The heifers were fed a roughage-based diet (90% barley silage and 10% rolled barley grain) throughout the feeding trial, which was broken down into 2 feeding periods with ADG of 0.94 and 0.90 kg?d(-1) in the first and second periods, respectively. The RFI was calculated for the entire period using different models, which included ADG, mid-metabolic BW, body composition, and feeding activity. Gain:feed ratio and Kleiber ratio were also calculated. Rank correlations among the RFI calculated from different models were obtained, as well as rank correlations between the 2 feeding periods for the feed efficiency measures. Including body composition and feeding activity only improved the R(2) by 1 to 5%. The rank correlations among the different models were high (90 to 95%) for RFI calculated for the entire feeding period. However, the RFI calculated within the second feeding period had greater rank correlation than the RFI calculated from the entire feeding period. Compared with G:F and Kleiber ratio, RFI gave lesser reranking between periods 1 and 2. About 49% of the heifers maintained their RFI class, whereas 51% of the heifers had a different RFI class in period 2. Furthermore, 41% of the heifers changed their RFI in period 2 by <0.5 SD, whereas the rest of the heifers changed by ≥0.5 SD. These results indicate that reranking exists in heifers despite receiving the same diet in the 2 feeding periods and that the reranking may be more serious in heifers (28%) with extreme RFI performances in each period.     

Acute phase protein response during acute ruminal acidosis in cattle

The aim of the study was to describe the acute phase protein and leukocyte responses in dairy heifers during acute, oligofructose-induced ruminal acidosis. The study included 2 trials involving oral oligofructose overload (17 g/kg BW) to nonpregnant Danish Holstein heifers. Trial 1 included 12 heifers all receiving oligofructose, and the experiment consisted of a 3 day control period prior to overload and 9 days surveillance afterwards. Eight heifers were fed grass hay and 4 were fed barley silage. Trial 2 included 10 heifers receiving oligofructose, 4 were euthanized 24 h after overload and 6 were euthanized 72 h after overload. Six heifers received tap water as control treatment and were euthanized 72 or 96 h later. Sampling of blood was performed at 6–48 hour intervals. Samples were analyzed for serum amyloid A (SAA), haptoglobin, and fibrinogen, and total white blood cell counts (WBC) were performed.     

Feeding strategies for dairy cattle. Comparison of flat rate feeding and standard feeding during early lactation

In a 14-week experiment beginning at week 4 postpartum, with 40 individually housed autumn calving cows a system of flat rate feeding (F) was compared with standard feeding (N). The basal ration consisted of a restricted amount of maize silage and ad libitum grass silage. Average daily concentrate DM consumed was 6.3 and 6.5 kg for treatment F and N respectively. Treatment F resulted in a non-significant higher forage DM intake. Covariant adjusted yields of milk (27.8 and 27.9 kg/d) and 4% fat corrected milk (28.3 and 28.3 kg/d) were not decreased by treatment F. The system of concentrate allocation had no effect on either milk composition or body weight changes. The results are discussed in relation to other data.     

Lead concentrations in blood and milk from periparturient dairy heifers seven months after an episode of acute lead toxicosis

In September 1988, 100 of 300 yearling dairy heifers developed blindness, tachypnea, foaming at the mouth, chewing, and facial fasciculations. Twenty-five animals died. Lead toxicosis was diagnosed based on the clinical signs and the presence of excessive concentrations of lead in whole blood, liver, kidney, and rumen contents of affected animals. The source of the lead was sudan grass silage that had been contaminated by soil that contained up to 77,000 mg/kg of lead. Lead concentrations were determined approximately 7 months after the acute episode of lead toxicosis. Whole blood and milk samples were obtained from heifers and a group of control cows 2 weeks prior to (blood only), at the time of, and 2 and 4 weeks after freshening. No lead was found in any of the milk samples (detection limit = 0.055 mg/liter). Animals that had been severely affected by lead toxicosis experienced a transient increase in whole blood lead concentrations at freshening that was not high enough to be considered toxic. No similar increases in blood lead were observed for control cows or heifers that had experienced milder toxicosis. These findings suggest that at parturition lead is mobilized into the blood of cattle previously exposed to excessive lead.     

Consumption and ruminating behavior in sheep. 3. Experiments on infertile female sheep of different breeds with reference to feed type and feeding duration

Ewes of the breeds merino fattening sheep, Stavropol merino and fertility hybrid were studied as to their consumption and ruminating behaviour after receiving a pelleted straw-concentrate mixture, maize silage and wilted silaged grass. During the feeding periods of 2 X 45 min or 2 X 180 min/d unlimited rations were available to the animals. With 86 min/d the sheep used the short feeding period nearly completely for feed intake. In the longer feeding period the sheep consumed 18% more feed in 161 min/d, ate more slowly, however, and ruminated somewhat less. In comparison with the straw-concentrate mixture, the silage rations were ruminated for shorter periods and less effectively, the number of ruminating movements per day and cycle was reduced, the breaks between bites became longer. The wilted grass silage stimulated ruminating even less than chopped maize silage. There were significant differences between the breeds in the ruminating frequency, which affected the number of ruminating movements per day and cycle.     

Factors associated with intersucking in Swiss dairy heifers

Intersucking is a problem that may lead to udder damage, mastitis, milk loss, and culling of breeding animals. To analyse the risk factors for intersucking in dairy heifers in Switzerland, we asked 130 randomly selected dairy farmers about a broad spectrum of environmental factors that might be associated with intersucking (such as housing conditions, management, and the feeding of calves and heifers). In total, 2768 heifers (Swiss Brown Cattle, Simmental and Holstein Friesian) were included of which 303 had ever performed intersucking. Data at the farm level were analysed using path analysis (linear and logistic regression). Two outcome variables were considered: the occurrence of intersucking on the farm and the proportion of intersucking heifers above the cut-off of 7.2%. Farms where calves had no access to barnyard or pasture, where calves were reared in pens in enclosed buildings, where heifers after weaning were not restrained while feeding, where heifers after weaning received <0.5 kg concentrate per day, and where heifers after weaning were fed ≥40% maize silage (dry-matter ratio) were most likely to have intersucking heifers.     

Outbreak of clinical listeriosis in sheep: evaluation from possible contamination routes from feed to raw produce and humans

We report the results of clinical and microbiological investigations on Listeria monocytogenes infections in a flock of 55 sheep and describe the implications for the safety of the raw milk and raw-milk cheeses produced in the on-farm dairy. The outbreak was caused by feeding grass silage, which was contaminated with 5 log10 CFU L. monocytogenes/g. Clinically, although having been fed from the same batch of silage, abortive (nine ewes), encephalitic (one ewe) and septicaemic (four ewes) forms of listeriosis were observed during the outbreak phase. As the starting point of feeding the contaminated silage was known we could calculate an incubation period of 18+/-2 and 26 days for the abortive and the encephalitic form of listeriosis, respectively. Pathologically, the septicaemic cases suffered from Listeria accumulation at comparable numbers in visceral organs but not in the brain. Only a single ewe developed central nervous symptoms and a rhomb-encephalitis was immunohistologically confirmed. In this case the infection proceeded from the nasal mucosa into the brain, with no infections of the liver, spleen and other visceral organs. Sampling of the cheese production chain, the farm environment and the persons living at the farm revealed the exposure of a farm-worker to an isolate genetically indistinguishable from the outbreak clone, obviously through the consumption of faecally contaminated bovine raw milk. The cheese under processing was free of Listeria because, as a result of intensive consultations, the farmer ensured a proper acidification of the cheese. The epidemiological findings suggest that food safety matters should be assessed in any case where infection of food-producing animals with potential human pathogens is observed.