Low phosphorus intakes by beef suckler cows in late pregnancy and early lactation

Two groups each of 10 suckler cows were given a basal diet of oat straw and pressed unmolassed sugar beet pulp for the last 19 weeks of pregnancy and the first 6 weeks of lactation. One group received 0.88 kg extracted soya bean meal (SBM) in pregnancy and 1.03 kg in lactation. The other was given 0.27 kg of a liquid supplement (LS) (containing inter alia urea and phosphoric acid) in pregnancy increasing to 0.33 kg in lactation. Both diets provided about the same amounts of digestible crude protein and about 10 g phosphorus (P) per day in pregnancy and 12 g P per day in lactation. Cows given SBM consumed marginally more straw but there were no differences in total diet digestibility. Cows given LS lost significantly more liveweight but their calves grew equally well. There were indications that cows given LS had slightly higher mean blood inorganic P and lower mean blood calcium (Ca) concentrations. Mean blood inorganic P concentrations were not below 1.4 mmol/l in pregnancy or 1.2 in lactation. There were no signs of reduction in voluntary straw intake or depraved appetite. When transferred to grass with a bull at the end of the experiment all cows were served within 24 days. It is concluded that these amounts of dietary P were adequate over the 25 weeks.     

肉牛日粮的营养供给量

1960～1998年间,美国所有各种肉类的人均年消费量增加了29％(折合成无骨肉计是从140lb增至180 lb),然而,此后38年间牛肉的人均消费量变化情况却与此不同,它从60 lb增至1976年的89 lb,又降至1998年的62 lb。在市场上,禽肉的竞争力愈来愈强劲。为了使牛肉在消费者选择肉类面前变得具有竞争力,就必须在从肉牛受孕起到牛肉放进陈列柜内止的全过程对营养、管理和市场销售服务予以密切关注。我们每年一度发表以此为题的文章,其目的就是为了提供最     

肉牛的日粮营养供给量

衰1生长和肥育肉牛的,养,要.动‘体重仙.).J口654刀NEm留豁*7.52371长谢回阂肠﹄代钙礴平1 .272.724一245 .817 .420.340.660.971271 .570.290.540.770.991 .2011 2 3 45 ..…,且2 3 459 1725犯3814 2739犯641 .12.23.34.45.5························……日维持需要t························……4.84 5.55 6.23 6.89 239 274 307 340 8 9 11 12 6 7 8 10.....············……旧增重所需净能伽cal)·········,········……1 .50 1.72 1.93 2.14 3 .21 3.6…     

Subclinical mastitis of beef cows

Two beef cow herds were investigated to determine the prevalence of subclinical mastitis and to determine whether it contributed to decreased weaning weight of calves nursed by affected cows. Quarter samples obtained about 30 days after calving were evaluated by the California mastitis test and by direct microscopic cell count. In 1 herd, a 92-cow confinement operation, 17 quarters of 12 cows were infected with Staphylococcus aureus, Streptococcus sp other than agalactiae, or Klebsiella sp. Mean 205-day adjusted weights were 203.9 kg and 218.2 kg for calves nursed by infected vs noninfected cows. In the other herd, a 75-cow range-pasture operation, 8 quarters of 8 cows were infected, all with S aureus. Mean 205-day adjusted weights were 162.5 kg and 174.6 kg for calves nursed by infected vs noninfected cows.     

Winter-annual pasture as a supplement for beef cows

In each of two experiments, 120 pregnant beef cows were stratified by body condition score, BW, breed, and age, randomly divided into six groups of 20, and assigned to one of six 5.1-ha bermudagrass (Cynodon dactylon [L.] Pers.) pastures (two replicates/ treatment) in early January to evaluate the use of winter-annual pasture as a supplement. All cows in Exp. 1 and 2 had ad libitum access to bermudagrass/dallisgrass (Paspalum dilatatum Poir.) hay plus three treatments: 1) a concentrate-based supplement fed 3 d/wk, 2) limit grazing on winter-annual pasture 2 d/wk (7 hr/ d; 0.04 ha x cow(-1) x grazing d(-1)), or 3) limit grazing on winter-annual pasture 3 d/wk (7 hr/d; 0.04 ha x cow(-1) x grazing d(-1)) sod-seeded into a portion of the pasture until mid-May. The seeded portion of pastures in Exp. 1 was planted with a mixture of wheat (Triticum aestivum L.) and rye (Secale cereale L.), but annual ryegrass (Lolium multiflorum Lam.) was added to the seed mixture in Exp. 2. In mid-May, cows were blocked by treatment and the previous sorting factors, randomly assigned to six new groups of 20, and placed on the six perennial pastures until calves were weaned. Groups of cows were exposed to a bull for 60 d beginning in mid-May. In Exp. 1 and 2, limit-grazing winter-annual pasture compared to the concentrate-based supplement or limit grazing 2 vs 3 d/wk did not affect (P > 0.15) cow BW. In Exp. 1, cows limit grazed on winter-annual pasture had a lower (P = 0.05) body condition score than cows fed the concentrate-based supplement in the early spring. However, in Exp. 2, cows limit grazed on winter-annual pasture had higher (P < or = 0.07) body condition score than cows fed the concentrate-based supplement. The conception rate of cows in Exp. 1 and 2 did not differ (P > 0.22) between cows fed concentrate-based supplements and cows limit grazed on winter-annual pasture. In Exp. 2, cows limit grazed 2 d/wk tended to have a greater (P = 0.10) conception rate than cows limit grazed 3 d/wk. In Exp. 1 and 2, birth weight, total gain, BW, and ADG of calves were not affected (P > 0.15) by treatment. We conclude that wheat and rye pasture is a marginal supplement for lactating beef cows. However, cows limit grazed 2 d/wk on winter-annual pasture of wheat, rye, and annual ryegrass as a supplement maintained BW and body condition score as well as cows fed the concentrate-based supplement. But, grazing pasture 3 vs 2 d/wk did not seem to affect performance of cows.     

Systemic salmonellosis in mature beef cows

Systemic infection of mature beef cows with Salmonella typhimurium resulted in death of cows, abortions, and premature births. Salmonella typhimurium was isolated from the kidney, liver, and spleen of cows but not from an aborted fetus. Diarrhea was not a prominent clinical feature of the epizootic. The source of the salmonella was not determined.     

Corticosteroid-responsive thrombocytopenia in two beef cows

Corticosteroid-responsive thrombocytopenia was identified in 2 beef cows. Clinical findings in 1 cow included hematoma formation, petechiation of mucous membranes, anemia, and persistent thrombocytopenia. Cow 2 was in its fourth month of gestation and had epistaxis, nasal mucosal petechiation, anemia, and thrombocytopenia. Treatment included parenteral administration of corticosteroids at immunosuppressive dosages. Cow 1 had a history of chronic hematoma formation and responded to long-term treatment with dexamethasone, but it relapsed 2 months after treatment was discontinued. Cow 2 had acute onset of clinical signs, responded to short-term treatment with prednisone, delivered a full-term, healthy calf, and remained clinically normal for at least 1 year after treatment was completed. Reported causes of thrombocytopenia in ruminants were ruled out or seemed unlikely; a definitive cause for thrombocytopenia in the 2 cows could not be established.     

Escape protein for beef cows: III. Performance of lactating beef cows grazing smooth brome or big bluestem.

Grazing trials were conducted utilizing individually supplemented lactating beef cows in a 2-yr study to determine the effect of supplemental escape protein (EP) on cow/calf performance during the active growth periods of smooth brome and big bluestem. Graded levels (0, .11, .23, and .34 kg of EP/animal from an equal-protein-basis mixture of blood meal and corn gluten meal were offered daily, replacing corn starch and molasses, which was used as the energy control. All cows received 582 g of supplemental DM/d. Analyses for the smooth brome study indicated a cubic response (P less than .05) to milk production and calf daily gain. No response to EP supplementation (P greater than .10) was observed for the big bluestem study. Analysis of esophageal extrusa samples collected throughout the grazing seasons for both years demonstrated that quality of forage selected by the animal decreased as the trial progressed. Using a 16-h modified dacron bag technique that did not adjust for microbial attachment, protein escaping degradation for smooth brome and big bluestem was estimated to range from 7.0 to 14.5% and 22.2 to 30.3%, respectively. There was limited response to a moderate level of EP supplementation of lactating cows grazing smooth brome, but calf gains were depressed by both the low and the high levels of EP. Lactating cows grazing big bluestem did not respond to EP supplementation, but added energy supplement depressed calf gains.     

Estrous behavior in confined beef cows

Forty-two postpartum beef cows were continuously monitored for behavioral signs of estrus until 100 d postpartum. Twice-weekly blood samples were collected and assayed for plasma progesterone concentrations. The duration of standing increased, recumbency decreased and intra-pen ambulation increased significantly on the day of estrus in comparison to the average of the 4 d prior to and after estrus. The average duration of the receptivity phase (standing when mounted) was 4.4 h, with a range of individual variation between 1 and 18 h. The highest occurrence of standing when mounted was observed during the first hour of the receptivity phase, gradually declining thereafter. Also, other recorded estrual activities, particularly being chin-pressed, being sniffed and sniffing other cows had their highest peak during the first hour of the receptivity phase. Plasma progesterone concentrations revealed a gradual increase in the postpartum estrus sequence. Based on the progesterone profile up to 100 d postpartum, 95% of the herd started to cycle regularly, 93% displayed mounting or being mounted during estrus, and 86% displayed receptivity consistently after initiation of regular cycling. The interval from parturition to first occurrence of a behavioral sign of estrus was 52.3 d (SD = 17.1 d).     

肉牛日粮的养分供给量（续）

矿物质 动物体总的矿物质或灰分含量,在整个干物质含量中所占的百分数很微小。一位作者曾经这样来描述一头牛(在非常粗略的基础上减去肠胃道内容物):水约占73％,蛋白质约为22％,而灰分则占5.3％,再加上少量的碳水化合物。Missoun大学的研究人员分析了若干头已繁殖过的动物体后,发现各种矿物质所占的量值比例为:钙1.3％、磷0.74％、钠0.16％、钾     

Effect of lasalocid on fall-calving beef cows

The effects of lasalocid on fall-calving beef cows were examined in a 196-d trial that began October 12, 1983. Forty-two crossbred cow-calf pairs were stratified to six groups by breed, calving date and sex of calf. Three replications of each of two treatments, 0 and 200 mg lasalocid X head-1 X d-1, were used. The cows were fed a combination of haylage and grass hay ad libitum. The cow-calf pairs were allowed access to pasture at all times, except during the breeding season. At this time they were kept in confinement to facilitate heat detection and artificial insemination. Cow weight changes and body condition (0 = very thin, 9 = very fat) were unaffected (P greater than .10) by feeding lasalocid to the cows. Twelve-hour milk production per cow, percent fat and percent protein were each determined three times during the trial. A slight increase in milk yield was observed in treated cows (P greater than .10). Percent milk fat and protein were also unaffected by treatment (P greater than .10). Lasalocid supplementation of cows did not affect calf gain or 205-d adjusted weaning weight (P greater than .10). Average days open was evaluated for the cows. There were no differences between treatments for actual average days open (P greater than .10). No detrimental effects were observed in long-term feeding of lasalocid to fall-calving beef cows.     

Pregnancy toxaemia of beef cows in Orkney

Pregnancy toxaemia in beef cows is assessed based on approximately 30 isolated cases seen in Orkney during the period 1974 to 1977. Case histories of nine of these are included. A mortality rate of over 90 per cent was recorded. The importance of nutrition and early detection is emphasised.     

Salmonellosis in a herd of beef cows

Two postparturient beef cows in a herd of 30 developed acute enteritis, with pyrexia and bloody diarrhea containing intestinal casts. Salmonella typhimurium phage type 66 was isolated from feces of both animals; both recovered after treatment with tetracycline. A third cow had died without treatment after showing similar signs.     

Maternal behavior of beef cows at parturition

Over an 11-yr period maternal behavior, calf birth weight and calf condition were recorded within 24 h for 2,684 parturitions. Maternal behavior was rated on a scale from 1 to 11, where 1 indicated extreme aggressiveness and 11 indicated no maternal attentiveness. Birth condition was rated on a scale from 1 to 9, with 9 being fattest and 1 thinnest. Respective breed means of Hereford, Angus, Charolais and Red POll were 6.2, 5.3, 6.0, and 5.7 for maternal behavior rating; 30.6, 27.3, 39.2 and 32.6 kg for birth weight, and 5.5, 4.7, 5.6 and 5.5 for birth condition. Heritability estimates for maternal rating, birth weight and birth condition were .06 +/- .01, .48 +/- .02 and .19 +/- .01, respectively. Genetic correlations between maternal rating and birth weight and condition were .04 +/- .05 and -.02 +/- .06, respectively. These results suggest that, in the population of cows studied, nongenetic influences were the primary cause of differences in aggressiveness of cows at parturition.     

Nutritional management of grazing beef cows.

In grazing operations, forage quality and availability are sometimes limited, and cattle are unable to consume enough nutrients from pasture forage to fulfill requirements. During such situations, supplemental or replacement feeding is necessary to meet production goals. A fundamental understanding of ruminant nutrition and forage management is helpful in deciding which feed or supplement type (ie, energy versus protein) best fits the goals of a specific beef production system. It is important to choose a delivery method and supplement form that provide the targeted amount of desired nutrients to each animal in the herd and that minimize input costs. The objective of this article is to serve as a resource for veterinarians as they provide nutritional management support to beef cow producers.     

Risk factors for post-partum anoestrus in Charolais beef cows in France

Data from 248 Charolais cows from 20 herds of the Puisaye region (Yonne, France) were collected during winter 1991–1992 to investigate risk factors affecting post-partum anoestrus. Blood was collected 60 days after calving; diagnosis of cyclicity was established by progesterone radioimmunoassay. Herd variables were housing type, lighting of herd accomodation, use of nutritional flushing and nutritional variables (protein and energy before and after calving), and individual variables were parity, ease of calving, body-condition score and body weight at calving and at Day 60, exposure to bulls and calving period. Sixty days post-partum, 62.1% of cows were cyclic. Logistic regression was used to calculate odds ratio (OR). A random effects model was used to take into account the two levels of variables (animal and herd). Although it was defined subjectively, lighting was the only significant herd-level risk factor. Odds of anoestrus were higher in dark than in light accomodation (OR = 6.2, CI 1.2–33.3). Primiparous cows had a higher anoestrus risk than multiparous cows (OR = 10.2, CI 2.9–36.5). Compared with light cows, heavy or medium weight cows at calving had a lower anoestrus risk (OR = 0.25, CI 0.07–0.91, and OR = 0.20, CI 0.07–0.61, respectively.