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Lactating Cows (lactating + cow)

Distribution by Scientific Domains

Medical Sciences	40%

Selected Abstracts

Diet selection of dry and lactating beef cows grazing extensive pastures in late autumn

GRASS & FORAGE SCIENCE, Issue 4 2006
A. Farruggia
Abstract The diet selection, made by twelve dry and twelve lactating spring-calving Salers beef cows at the end of the grazing season on an extensively grazed natural mountain pasture in central France, was compared. Sward structure, selection bites, daily grazing time and digestibility of the diet were measured in mid-October (P1) and mid-November (P2). Live weights were measured twice monthly throughout the experiment. Daily milk production was assessed in the week before the grazing behaviour measurements. Lactating cows grazed more selectively than dry cows: they took more bites on green patches (0·20 vs. 0·13 of total bites, P < 0·01; Jacob's selectivity index: 0·13 vs. ,0·25, P < 0·001), which is consistent with the higher overall nitrogen concentration in faeces (18·1 vs. 17·3 g kg,1 DM, P < 0·05). Lactating cows tended to slightly increase their daily grazing time compared with dry cows (on average 9·9 vs. 9·5 h, P = 0·07) and grazed faster in mid-November (74 vs. 69 bites min,1, P < 0·05). The lactating cows lost more live weight (,24 vs. ,12 kg cow,1, P < 0·05) between P1 and P2. A positive correlation was found between consumption of green patches by lactating cows and their daily milk production in P2 (r = 0·574, P = 0·05), whereas no correlation occurred between individual milk production and liveweight loss. Dry cows were less selective, which supports management practices that promote the use of cows with low requirements on extensively grazed pastures in late season. [source]

Effects of rumen-protected methionine in a low protein ration on metabolic traits and performance of early lactating cows as opposed to rations with elevated crude protein content

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5 2000
T. F. Kröber
Summary A 5-week experiment with 24 multiparous early lactating Brown Swiss cows was conducted to investigate the effects of supplementary rumen-protected methionine in conjunction with dietary protein reduction on metabolism and performance after 1 week of control measurement. Three rations containing 175, 150 and 125 g of crude protein/kg feed dry matter were supplemented with methionine. The fourth ration, also only containing 125 g of crude protein/kg dry matter, remained unsupplemented. The four treatment groups had a similar metabolic supply of other essential amino acids, protein and energy, as calculated by various approaches. The two low protein rations were, however, slightly deficient in ruminally degraded protein. Treatment effects remained low on feed intake, forage meal pattern, milk yield and fat as well as lactose content. In contrast, the content and yield of milk protein significantly declined only in the unsupplemented low protein ration relative to the initial value. Compared with this ration, the decline in milk protein yield was clearly delayed in the supplemented low protein ration. Blood plasma methionine tended to be reduced without supplementation and to be increased with additional methionine. Supplementation of methionine reduced other plasma amino acids. Plasma insulin, glucose, lactate, ketone bodies and aspartate amino transferase activity indicated a certain liver stress and a somewhat elevated energy requirement with high and particularly with low protein content (when unsupplemented). Methionine improved metabolic protein utilization, followed by the lowest plasma, urine and milk urea levels in the supplemented low protein diet. In conclusion, no major adverse effects were assessed under the conditions tested. Supplementation of methionine may nevertheless be useful in rations with particularly low protein content fed to early lactating cows in order to prevent negative long-term effects which were only visible here as trends. Zusammenfassung Auswirkungen von pansengeschütztem Methionin in einer Niedrigproteinration im Vergleich zu Rationen mit erhöhtem Rohproteingehalt auf Stoffwechselmerkmale und Leistung von frischlaktierenden Milchkühen In einem fünfwöchigen Experiment mit 24 frischlaktierenden Braunviehkühen wurden die Auswirkungen einer Ergänzung mit pansengeschütztem Methionin bei gleichzeitiger Reduktion der Proteinzufuhr nach einer einwöchigen Kontrollphase geprüft. Drei Rationen mit 175, 150 und 125 g Rohprotein/kg T wurden mit Methionin ergänzt. Eine weitere Variante, ebenfalls nur mit 125 g Rohprotein/kg T, wurde nicht supplementiert. Die vier Varianten stellten gemäß verschiedener Futterbewertungsysteme eine vergleichbare metabolische Versorgung mit den übrigen essentiellen Aminosäuren, Protein und Energie sicher. Die Niedrigproteinvarianten enthielten allerdings etwas zu wenig pansenabbaubares Protein. Futteraufnahme, Muster des Grundfutterverzehrs, Milchleistung sowie Fett-und Laktosegehalt der Milch zeigten nur geringe Reaktion auf die Behandlungen. Milchproteingehalt und -menge waren nur in der nicht ergänzten Niedrigproteinvariante relativ zum Ausgangswert signifikant verringert. Im Vergleich zur unsupplementierten Niedrigproteinration war dagegen der Abfall mit Ergänzung deutlich verzögert. Gegenüber dem Ausgangswert war die Methioninkonzentration im Blutplasma ohne Ergänzung tendenziell erniedrigt, mit Ergänzung erhöht. Es erfolgte eine Verringerung der Plasmakonzentration anderer Aminosäuren durch die Methioninergänzung der Niedrigproteinration. Die Plasmaniveaus von Insulin, Glucose, Laktat, Ketonkörpern und Aspartataminotransferase-Aktivität lassen auf eine gewisse Leberbelastung und einen etwas höheren Energiebedarf mit hohem und besonders mit niedrigem Proteingehalt (unsupplementiert) schließen. Die Zulage an Methionin verbesserte die metabolische Proteinverwertung, so dass die Harnstoffgehalte in Blut, Milch und Harn in dieser Niedrigproteinvariante am niedrigsten waren. Insgesamt ergaben sich keine grösseren ungünstigen Effekte unter den getesteten Bedingungen. Dennoch könnte die Ergänzung von Rationen mit besonders niedrigem Rohproteingehalt mit Methionin beim Einsatz an frischlaktierende Kühe hilfreich sein, um negative Langzeitwirkungen zu verhindern, die sich hier lediglich andeuteten. [source]

Effects of a Progesterone-Based Oestrous Synchronization Protocol in 51- to 57-Day Postpartum High-Producing Dairy Cows

REPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2010
I Garcia-Ispierto
Contents The aim of this study was to investigate the effect of applying a progesterone-based oestrous synchronization protocol at 51,57 days postpartum in high-producing dairy cows. The data analysed were derived from 1345 lactating cows. Cows between 51 and 57 days postpartum were assigned to the groups: control, PRID (receiving a progesterone-releasing intravaginal device for 9 days, and prostaglandin F2, 24 h before PRID removal) or GnRH,PRID (the same as the PRID group plus GnRH at PRID insertion). Oestrus was detected by using pedometers and confirmed by examination of the genital tract at AI. Oestrous and conception rates before days 71,77 postpartum, pregnancy loss in early pregnant cows or the cumulative conception rate registered on day 120 postpartum were considered as the dependent variables in four consecutive logistic regression analyses. Based on the odds ratios, the oestrous rate increased by a factor of 1.73 in cows showing oestrus before treatment for each unit increase in the number of previous oestruses; decreased by a factor of 0.44 in the control group with respect to the treatment groups; and by a factor of 0.61 in cows without luteal structures at treatment with respect to cows with corpora lutea. The conception rates of cows inseminated before days 71,77 postpartum remained similar across the groups, whereas the likelihood of pregnancy loss for cows becoming pregnant during this period was 0.11 times lower in the PRID group than in the control. Based on the odds ratio, the likelihood of a higher cumulative conception rate on day 120 postpartum: increased in cows showing oestrus before treatment by a factor of 1.41 for each unit increase in the number of previous oestruses, was reduced 0.56-fold in control cows compared with treated cows, and was also reduced by a factor of 0.98 for each kilogram of milk production increase recorded at treatment. In conclusion, although oestrous synchronization programmes performed in this study did not improve fertility, cows treated with progesterone could be inseminated earlier than untreated cows, such that the treatments increased the cumulative pregnancy rates determined on day 120 postpartum. In addition, fewer pregnancy losses were observed in early pregnant cows in the PRID group than the GnRH,PRID group. [source]

Clinical acidosis in a Gippsland dairy herd

AUSTRALIAN VETERINARY JOURNAL, Issue 6 2005
E. BRAMLEY
Objective: To report on spontaneous clinical and subclinical acidosis in a large dairy herd, to evaluate the diets and feeding strategies involved, and to report on measures of rumen function in the cows affected. Design: A Gippsland dairy herd was sampled as part of a wider randomised cross-sectional study that examined the prevalence, risk factors for, and effects of, acidosis on rumen function of dairy cattle. Three herds on the farm were involved in the study: the transition herd (cows 3 weeks prior to calving), the very fresh lactating herd (1lactating cow diet included 6.75 kg dry matter triticale per cow per day with total concentrate fed being 8.1 kg dry matter per cow per day in the milking parlour. Silage, lucerne cubes, hay and pasture (herd 2 only) was also fed to the lactating cows with the estimated total dry matter intake for cows in herds 1 and 2 being 13.7 kg and 20.8 kg per cow per day respectively. Three primiparous and five multiparous cows in early lactation (<100 days in milk) were randomly selected from each of two lactating herds: herds 1 and 2. Rumen fluid was sampled from each cow by both rumenocentesis and stomach tube. The rumenocentesis samples were tested for pH at the time of sampling. Stomach tube samples were frozen and subsequently tested for volatile fatty acid, ammonia, and D- and L-lactate concentration. Results: In the very fresh herd, there was a high prevalence of severe lameness and scouring, coupled with a mean rumen pH 5.67, low mean total volatile fatty acid concentration 71.0 mM and high mean concentrations of L- and D-lactate,(7.71 mM and 7.31 mM), respectively. Cows in the fresh herd had moderate signs of scouring and lameness. A lame herd comprising approximately 50 cows separated from the fresh herd was also present on the farm. The mean rumen pH of the fresh herd was 5.74 and mean rumen concentrations of volatile fatty acids, ammonia, L- and D-lactate were within ranges considered normal. Conclusions: The transition diet failed to supply sufficient energy and protein for maintenance of cows of this live weight in late gestation. The diet fed to the very fresh herd was low in effective fibre and contained an excessive content of non-structural carbohydrate in the form of processed, rapidly fermentable grain. The sudden change from the transition diet to the diet fed to the very fresh herd probably also precipitated the outbreak of acidosis. This case report provides unique detail, including information on diets and rumen parameters, of an outbreak of acidosis in a pasture-fed herd. [source]