The effects of dietary urea and ammonium sulphate on the yield and composition of sheep milk

1971 ◽  
Vol 38 (3) ◽  
pp. 309-314 ◽  
Author(s):  
G. Tanev

SummaryAn experiment lasting 4 years has been carried out with 4 groups (3 test and a control) of 10 sheep. Non-protein nitrogen (NPN) (as urea, ammonium sulphate or a mixture of the two) replaced 25% of the dietary nitrogen in the first 2 years and 50% in the second 2 years. The yields of milk, protein and fat were generally depressed in the test groups but not all of the differences reached significance. In the group receiving ammonium sulphate, the milk fat percentage was higher than in the control group in all years and the protein percentage was higher in the last 2 years. Contrary to results elsewhere, the yield of lactose was depressed in all test groups. In the urea group, the content of minerals and of calcium in the milk was significantly less than in the control groups. The total amount of NPN and its components (ammonia, urea and creatine) in milk were not affected by the substitution of NPN in the rations.

1973 ◽  
Vol 40 (3) ◽  
pp. 323-328
Author(s):  
G. Tanev

SummaryA 23-week trial was conducted using 4 groups each of 6 ewes to study the effects on milk yield and composition of substituting non-protein nitrogen (NPN) for 75 % of the dietary nitrogen. The control group received a winter ration which included silage followed by a summer ration containing lucerne. The test groups received substitutes of urea, ammonium sulphate, or urea+(NH4)2SO4. The milk yield of the test groups was lower (P< 0·01) than that of the control group. Depression of the fat content of the milk reached statistical significance (P< 0·01) in the groups receiving (NH4)2SO4and urea+(NH4)2SO4. In comparison with the control group, the protein content of the milk was greater in the group receiving urea and smaller in the other 2 test groups. The milks of the test groups had lower amounts of essential amino acids in the free state and higher amounts of non-essential amino acids than did the control milk. Milk-clotting time was increased in the test groups; the increase was greatest (P< 0·01) for the group receiving (NH4)2SO4and least (P< 0·05) for that receiving urea.


1996 ◽  
Vol 36 (7) ◽  
pp. 763 ◽  
Author(s):  
M Reeves ◽  
WJ Fulkerson ◽  
RC Kellaway

Three studies were conducted to examine the production response of Friesian cows grazing well-managed lukuyu (Pennisetum clandestinum) pasture to supplementation with a cereal grain concentrate, with and without the inclusion of formaldehyde-treated protein meal. Mean (¦ s.e.) levels of nutrients in the pasture (g/kg DM) on offer were: 205 ¦ 3 crude protein; 683 ¦ 7 in vitro organic matter digestibility; 239 ¦ 2 acid detergent fibre; 615 ¦ 8 neutral detergent fibre and 4.47 ¦ 0.16, 2.51 ¦ 0.06, 31.96 ¦ 0.98, 0.39 ¦ 0.03 and 3.18 ¦ 0.09 of calcium, phosphorus, potassium, sodium and magnesium, respectively. Study 1 was a 3-farmlet study conducted over 45 days (March-April 1993) involving cows 5-6 months into lactation, which compared 3 levels of concentrate feeding at 0 (R0), 3 (R3) or 6 (R6) kg crushed barley/cow.day. Study 2 was an 18-day extension of study 1 with animals in the seventh month of lactation. The concentrate fed was 72% barley and 24% formaldehyde-treated sunflower meal. Pasture intake of individual cows was determined using an alkane technique. Mean milk yields (L/cow. day) in study 1 were 14.2, 18.3 and 18.0, and in study 2 were 12.5, 18.5 and 17.4 for treatments R0, R3 and R6, respectively. Milk fat (3.77 v. 3.26%), but not milk protein, content of the Ro cows was significantly higher than R6 cows in study 1 only. In study 2, the apparent whole-diet digestibility remained constant as concentrate level rose, indicating a negative effect of concentrate fed on forage digestibility in the absence of buffers. Study 3 was a 3 x 4 factorial design plus a 'control' group (0.5 kg barley/cow.day used as a carrier for minerals) to examine the milk production response to 3 levels of concentrate feeding (3, 6 and 9 kg/cow.day) with 4 levels of formaldehyde-treated canola meal (FTCM; 0, 20, 40 and 60% of concentrate). Rations were iso-energetic within levels of concentrates fed. The control group had significantly lower milk production (17.2 L/cow.day), as well as milk protein (2.90%), plasma urea (PU) (5.90 mmol/L) and P-hydroxybutyrate (G-OHB) (0.525 mmo1L) than other treatment groups. The mean milk production response of 0.6 L milk/kg concentrate fed in study 3 at the 3 kg/day level of feeding was lower than observed in studies 1 and 2 (1.4 and 2.0 L/kg concentrate, respectively). The level of metabolisable energy in the concentrate in study 3 had a significant influence on milk production, milk fat and milk protein levels. Plasma glucose and G-OHB levels significantly increased with the incorporation of FTCM into the concentrate. Nonesterified fatty acid levels dropped significantly below levels of other treatments at the lowest level of inclusion of FTCM. PU levels generally increased in response to increasing metabolisable energy and inclusion of FTCM in the concentrate, with an interaction between them. Milk urea (MU) levels (mmol/L) showed a significant linear (P<0.001; r2 = 0.44) relationship to PU levels (mmol/L) as follows: MU = 0.167 + 0.272PU.


Author(s):  
D. Tristant ◽  
C. A. Moran

SummaryThe following trial was conducted to evaluate the impact of feeding Yea-Sacc® (YS; Alltech Inc, USA), a zootechnical feed additive based on a live probiotic strain of Saccharomyces cerevisiae, to lactating dairy cows over a 12 week period. Sixty-four primiparous and multiparous Holstein dairy cows, grouped to give similar range of parity, physiological and milk production stages, were selected for the study. Cows were equally allocated to either a control feed group or a diet supplemented with YS (32 cows per treatment). The test diet was formulated to include YS (Yea-Sacc® Farm Pak) incorporated in the total mixed ration (TMR), supplying a target dose of 5 × 107 CFU/kg feed dry matter (DM). This target dose delivered 1 × 109 CFU/cow/day, for a cow consuming 20 kg feed (DM basis) daily. Each cow was considered a replicate unit. Cows were fed a nutritionally adequate total TMR plus hay and a supplementary protein/energy concentrate (calculated according to milk yield) for 12 weeks, supplied once a day after the morning milking. Weigh backs of feed were recorded daily, with refusals being maintained at 3% of the total intake. During the 12 week study period, YS had significant beneficial effects on milk production (+0.8 kg/day; P = 0.003), energy corrected milk production (+1.4 kg/day; P < 0.0001), synthesis of milk protein (+36 g/day; P = 0.001), milk protein content (+0.3 g/kg; P = 0.009), and milk urea content (−0.09 mg/l; P = 0.004). The synthesis of milk fat was similar between treatments but milk fat content was lower for the YS group compared to the control group (−1.1 g/kg; P = 0.0002). Lactose content was always higher (+0.8 g/kg; P < 0.0001) for the YS group, indicating enhanced energy utilisation. In general, the effect of YS was higher during the first study period (one to seven weeks), when cows were in early lactation and the production potential was higher. YS cows produced significantly more milk during the study, and an additional 220 kg milk per cow was sold from this group from the output measured from the beginning of the study to two weeks post-trial. However, the statistical analysis including the post-study period did not show a significant effect. The 305-day simulated milk production was higher for the YS group (+400 kg/cow) but again the difference was not significant. In conclusion, YS at a target dose of 5 × 107 CFU/kg DM improved milk production and milk quality in healthy dairy cows. In addition, when the data were included in a whole-farm model, feeding YS reduced methane emissions by 4%, reduced the number of animals required for the desired milk production by 4% and increased overall farm margins by 1.4%.


1978 ◽  
Vol 39 (1) ◽  
pp. 181-192 ◽  
Author(s):  
R. Dawson ◽  
G. Milne

1. Male rats of approximately 120 g body-weight were maintained on a commercial stock diet containing 204 g crude protein (nitrogen × 6.25)/kg, a hydroxyproline-free high-protein (HP) diet containing 200 g casein/kg as the only protein source, or a low-protein (LP) diet containing 40 g casein/kg. After 6 weeks on these diets half of each group was transferred to a non-protein (NP) diet and the experiment was continued for a further 6 weeks. Animals from each group were killed at 4 d, 3 weeks and 6 weeks after the transfer to the NP diet.2. Throughout the experiment the urinary excretion of N, hydroxyproline and creatinine, and the content and solubility of the skin collagen were determined.3. When compared with a control group killed at the beginning of the experiment the rats maintained on the LP diet showed an increase of 25% in total N content of the skin but collagen content increased by 100%. Rats transferred from the HP to the NP diet lost both N and collagen from the skin, but those transferred from the LP to the NP diet lost N but increased the collagen content by 42%.4. Protein deprivation brought about marked changes in the solubility of the skin collagen, suggesting an increase in the rate of maturation of skin collagen.


1999 ◽  
Vol 79 (2) ◽  
pp. 235-241 ◽  
Author(s):  
D. Pacheco-Rios ◽  
W. C. McNabb ◽  
J. P. Hill ◽  
T. N. Barry ◽  
D. D. S. Mackenzie

Two experiments (mid- and late lactation) were conducted to test whether methionine (Met) limited milk production in Friesian cows fed sole diets of fresh perennial ryegrass–white clover pasture. In mid-lactation (exp. 1), 26 cows were assigned to one of three treatments: ruminally protected oral DL-Met (15 g d−1), continuous intrajugular infusion of L-Met (15 g d–1) and control. Twelve animals from exp. 1 were used during late lactation (exp. 2) and distributed in two experimental groups: ruminally protected oral DL-Met (15 g d−1) and control. Dry matter, metabolizable energy, crude protein and Met intakes, milk yield and composition and blood Met, cysteine and urea were measured. Oral and intravenous Met supplementation increased blood Met concentration by 50–90% compared with controls. Met supplementation did not alter the concentration of milk fat, protein or lactose in either experiment. Met supplementation had no significant effects on yields of fat, lactose, casein, whey proteins or non-protein nitrogen during mid-lactation. In late lactation, Met supplementation did not affect milk protein composition or yield of milk components, with exception of a decrease (P < 0.05) in the yield of β -casein. Intravenous Met supplementation increased (P < 0.05) the efficiency of conversion of pasture N to milk protein in mid-lactation. Key words: Dairy cows, methionine, ruminally protected methionine, milk protein, casein, fresh pasture diets


2005 ◽  
Vol 45 (4) ◽  
pp. 331 ◽  
Author(s):  
W. J. Fulkerson ◽  
K. McKean ◽  
K. S. Nandra ◽  
I. M. Barchia

Two experiments were conducted, each over several months, when cows grazed either ryegrass (September–November 2001) or kikuyu (February–March 2002) pastures, to assess the effects of accurately allocating feed on a daily basis to lactating Holstein–Friesian dairy cows. In each case, 28 cows were randomly stratified into 2 equal groups on the basis of milk and milk component yield, liveweight, age and days in lactation. The metabolisable energy requirements of the animals were estimated from standard established requirements. In each experiment, both groups of cows received the same amount of supplement over a period that was equivalent to a pasture regrowth cycle of 12–16 days. The control group received a set amount of supplements each day, while supplements fed to the adjusted group varied, dependent on pasture available. Available pasture was varied from 7 to 21 kg DM/cow.day (above a stubble height of 5 cm), to mimic the variation found on well-managed dairy farms. When pasture available was above the predicted requirement for cows in the adjusted group, pasture availability was restricted to predicted requirements and the extra milk that could be produced from the spared pasture was estimated. However, cows in the control group had the opportunity to eat more pasture if allocated more than required. This could result in more milk being produced, a gain in liveweight, and/or a higher post-grazing pasture residue (and hence potentially improve pasture regrowth). If less pasture than required was allocated to the control group, production could reduce or the cows might graze harder. Thus, in the control group the proportion of forage to supplement remained relatively constant, but intake varied in relation to pasture allocated, while for the adjusted group the total intake was kept relatively constant. In experiment 1 (ryegrass), the milk yield, percentage of milk fat and liveweight change of cows in the control and adjusted groups was not significantly different. However, the cows in the adjusted group produced 0.016 kg/cow.day more milk protein. As the control group ate 0.35 kg DM/cow.day more ryegrass pasture (P = 0.008) it is assumed that accurate daily allocation of feed improved feed efficiency. In experiment 2, the milk yield and percentage of milk protein of cows grazing kikuyu pastures was not significantly different between groups but the percentage of milk fat and covariate-corrected liveweight at the end of the experiment was higher in the control group than in the adjusted group. The pasture spared by cows in the adjusted group was predicted to produce 8.9% more milk when grazing ryegrass pasture and 12.3% when grazing kikuyu pasture. Linear regression analysis of pasture on offer on post-grazing pasture residue was not significant for the cows in the adjusted group but was significant for the control group cows when grazing either pasture, indicating success in accurately allocating supplementary feed to maintain a constant grazing pressure. The results of this study should assist dairy farmers in deciding whether the effort required to allocate feed accurately to dairy cows on a daily basis, is worthwhile.


Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 576 ◽  
Author(s):  
Boakari ◽  
Ali ◽  
Dini ◽  
Loux ◽  
Fernandes ◽  
...  

High blood urea nitrogen (BUN) decreases fertility of several mammals; however, the mechanisms have not been investigated in mares. We developed an experimental model to elevate BUN, with urea and control treatments (7 mares/treatment), in a crossover design. Urea-treatment consisted of a loading dose of urea (0.03 g/kg of body weight (BW)) and urea injections over 6 hours (0.03 g/kg of BW/h). Control mares received the same volume of saline solution. Blood samples were collected to measure BUN. Uterine and vaginal pH were evaluated after the last intravenous infusion, then endometrial biopsies were collected for RNA-sequencing with a HiSeq 4000. Cuffdiff (2.2.1) was used to identify the differentially expressed genes (DEG) between urea and control groups (false discovery rate-adjusted p-value < 0.1). There was a significant increase in BUN and a decrease of uterine pH in the urea group compared to the control group. A total of 193 genes were DEG between the urea and control groups, with five genes identified as upstream regulators (ETV4, EGF, EHF, IRS2, and SGK1). The DEG were predicted to be related to cell pH, ion homeostasis, changes in epithelial tissue, and solute carriers. Changes in gene expression reveal alterations in endometrial function that could be associated with adverse effects on fertility of mares.


1997 ◽  
Vol 77 (4) ◽  
pp. 735-737 ◽  
Author(s):  
W. C. Gardner ◽  
M. A. G. von Keyserlingk ◽  
J. A. Shelford ◽  
L. J. Fisher

Twenty–one multiparous Holsteins were used in a cross over design with two 28-d periods. Cows were randomly assigned to two treatments to assess the effect of textured and pelleted concentrates fed with alfalfa cubes on feed intake, milk yield, milk composition and rumen volatile fatty acid concentrations. Those animals receiving the textured concentrate had significantly (P < 0.05) higher milk yield and milk fat percentage than did those animals fed the pelleted concentrate. A significant difference in the ratio of milk protein to milk fat was also observed with the cows receiving the pelleted concentrate having a ratio of 1.31 and the cows receiving the textured concentrate a ratio of 1.02. No significant (P < 0.05) differences were observed between the textured and pelleted feeds in total or individual volatile fatty acid concentrations. These results indicate that the feeding of textured concentrates can lead to an increase in milk fat production when compared with the feeding of pelleted concentrates. Key words: Dairy cattle, milk composition, textured and pelleted concentrate, VFA


2021 ◽  
Vol 901 (1) ◽  
pp. 012026
Author(s):  
V G Kosolapova ◽  
N P Buryakov ◽  
O G Mokrushina ◽  
A V Kosolapov ◽  
D E Aleshin

Abstract Research has been carried out on the use of the symbiotic “Rumimaster” in balanced diets of highly productive cows in the conditions of the breeding plant “Kirovskaya meadow-bog experimental station”. The experiment was carried out on two groups of animals in the middle of lactation with a duration of 90 days. The inclusion of the feed additive “Rumimaster” in the diet of experienced cows contributed to an increase in the gross production of natural and 4% fat milk by 124.5 kg and 128.4 kg, the yield of milk fat and milk protein by 5.2 and 4.1 kg, respectively. … The differences between the groups for these parameters were in the range of 5.1-5.7%. The productivity of cows for 305 days of lactation in the experimental group was higher than in the control by 7.5%. The symbiotic “Rumimaster” promoted the activation of digestion processes, which was reflected in the increase in the time of feed consumption and the duration of the chewing gum. The cows of the experimental group showed an increase in the level of digestibility of the main nutrients. In terms of the digestibility of crude protein and crude fiber, the experimental group of cows significantly exceeded the indicators of the control group by 3.3 and 3 absolute percent, respectively. The blood biochemical parameters of the animals of the experimental and control groups were within the physiological norm. The economic evaluation of the research results showed the effectiveness of the use of the symbiotic “Rumimaster” in the diets of lactating cows, which was expressed in the receipt of additional profit from one cow in the amount of 1,344.79 rubles for the period of experience and an increase in the profitability of milk production by 2.1 absolute percent.


2019 ◽  
Vol 15 (4) ◽  
pp. 59-72
Author(s):  
Anna Jarzynowska

A study was conducted on samples of raw sheep milk and rennet cheese produced from it. The milk was obtained from ewes of the coloured variety of Polish Merino, from February to April. The sheep were housed indoors and fed preserved roughage and a mixture of concentrate feeds. Three feeding groups were established: group I ‒ control, fed without the addition of herbs to the concentrate feed, and groups II and III, in which a herb mixture was added to the concentrate feed in the amount of 10 and 20 g/sheep/day, respectively. Six experimental batches of bundz rennet cheese were made from the milk, and the effect of the addition of herbs to the diet on the lipid profile of the milk and cheese was analysed. The results indicated that the addition of herbs to the winter diet of sheep in the amount of 10 and 20 g/sheep/day significantly increased the content of the acid C4:0 in the raw milk used for cheese making, by 11.5% and 20.0%, respectively (P≤0.01), relative to the control group. C4:0 content in the raw milk was also increased in group III by 7.6% compared to group II (P≤0.05). The herbs had no statistically confirmed effect on other parameters of the health-promoting quality of the milk fat and the rennet cheese. In the cheese fat from group I produced from sheep milk obtained in the period from 69 to 137 days of lactation, there was an increase in the content of SFA and a decrease in UFA during the course of the experiment. The addition of herbs to the concentrate feed of the sheep improved the fatty acid profile of the fat of bundz cheese made from milk obtained from the 97th day of lactation. The experimental factor also reduced the cholesterol content in the raw milk in group II by 26.8% and in group III by 21.2% (P≤0.01) compared to group I. It did not affect the content of this lipid in rennet cheese.


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