The Effect of Level of Available Carbohydrate, Offered as a Supplement to a Forage Based Diet, on Intake, Milk Yield and Milk Composition.

Author(s):  
Rosemary Mansbridge

It has been reported (Castlejon and Leaver 1990, Hill and Leaver 1991) that when offered as the sole forage intakes of urea treated whole crop cereals (UWCC) were high. However energy output in milk and liveweight change was less than expected from calculations of energy intake.The level of crude protein (CP) in UWCC is high, typically in the range 200-300 g CP/kg DM. It has been suggested that a non-synchronous supply of available energy and rapidly available nitrogen to the rumen microorganisms was responsible for the low efficiency of utilization reported.The work described here was carried out to determine whether the utilization of diets containing UWCC could be improved by increasing the supply of readily available carbohydrates to the rumen micro-organisms.

1970 ◽  
Vol 37 (3) ◽  
pp. 481-491 ◽  
Author(s):  
F. J. Gordon ◽  
T. J. Forbes

SummaryEight lactating cows were used in a Latin square experiment, to study the associative effects of level of energy and protein intake on milk yield and composition. Four diets were used, supplying 80 and 120% of estimated energy requirements and 80 and 120% of estimated protein requirements. The level of energy intake significantly affected milk yield, milk energy output, percentage butterfat, ash and non-protein nitrogen. The level of protein intake only significantly affected milk energy output and the non-protein nitrogen content of the milk. Although only the interaction of the effects of energy and protein intake on the milk content of solidsnot-fat (SNF) and ash was significant, it was evident that the effect of each of these factors on milk yield or composition was related to the level of the other in the diet.Input-output relationships within each protein level were used to compute the response in milk energy output and bodyweight change to a change in energy intake. These showed a greater partitioning of additional energy toward milk energy output with the high than with the low protein level. Multiple regression analysis within each level of protein intake was used to partition energy intake between that used for maintenance, milk energy output and liveweight change. The results showed efficiencies of utilization of metabolizable energy for milk output of 63 and 50% on the high- and low-protein diets, respectively.Nitrogen balance data are presented.


2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 779-779
Author(s):  
A. Ostrensky ◽  
G. Negro ◽  
A. M. D. Santos ◽  
A. Anater ◽  
D. R. Ribeiro ◽  
...  

1990 ◽  
Vol 51 (1) ◽  
pp. 1-13 ◽  
Author(s):  
C. S. Mayne

ABSTRACTHerbage from the first regrowth of perennial ryegrass based swards was direct-ensiled following treatment with either an inoculant of Lactobacillus plantarum (Ecosyl, Imperial Chemical Industries pic) at 3·0 1/t, formic acid (850 g/kg) at 2·9 1/t, or no additive (control). During harvesting, alternate loads of inoculant material were treated with an absorbent polymer (ammonium polyacrylamide) at the rate of 1 kg/t herbage and ensiled in separate 100-t capacity silos. The mean dry matter (DM) and water soluble carbohydrate concentrations of herbage used for the four treatments was 157 and 120 g/kg respectively. Lactic acid levels post ensiling increased more rapidly in inoculant-treated herbage than with the other treatments. Formic acid and inoculant-treated silages were well preserved whereas control and inoculant-plus-polymer silages were only moderately well preserved. Losses of DM during ensilage were greater with the formic acid treatment with DM recovery values of 0·78, 0·72, 0·76 and 0·73 for the control, formic acid, inoculant and inoculant-plus-polymer silages respectively. Treatment of herbage with an absorbent polymer prior to ensiling resulted in a proportional reduction in effluent volume of 0·2 whereas formic acid treatment increased effluent flow by 0·28. The silages were evaluated in a changeover design experiment with two periods each of 4 weeks duration, using 24 British Friesian dairy cows. Animals were housed in individual stalls and in addition to the treatment silages, received 5 kg/day of supplement containing 193 g crude protein per kg DM. Silage intakes were increased by proportionately 0·10, 0·14 and 0·05 respectively with the formic acid, inoculant and inoculant-plus-polymer treatments compared with the control. The increased silage intakes with the inoculant treatment were reflected in an increased milk yield of 1·1 kg milk per day whereas formic acid and inoculant-plus-polymer treatments had no significant effect, although formic acid treatment did result in a significant increase in milk fat concentration. There were no major differences between treatments in energy or nitrogen digestibility, when determined on a complete ration basis. In conclusion, a large milk yield response was obtained as a result of treatment of herbage with inoculant prior to ensiling and this resulted from increased silage and hence energy intake. Treatment with formic acid increased silage and energy intake but had no effect on milk energy output.


1989 ◽  
Vol 48 (2) ◽  
pp. 305-317 ◽  
Author(s):  
A. C. Peoples ◽  
F. J. Gordon

ABSTRACTThis study was designed to examine the influence of pre-wilting and season of harvesting of silage on milk production and food utilization by dairy cattle and also the response to protein and fat concentration of the supplement given with silage. Twenty-four lactating British Friesian cows were used i n a four-period, partially balanced, change-over design experiment to evaluate 12 treatments consisting of three silage types (spring harvest unwilted (lUnW), autumn harvest unwilted (3UnW) and autumn harvest wilted (3W), each offered in addition to supplements containing both two crude protein levels (160 and 210 g/kg fresh weight) and two levels of inclusion of a fat supplement (0 and 100 g/kg fresh weight) in a 3 × 2 × 2 factorial arrangement. All supplements were offered at the same rate of 6·8 kg/day. Total diet digestibility and food utilization studies were carried out on all animals at the end of the third and fourth experimental periods.The wilted silage (3W) had a higher digestibility than the unwilted (3UnW) material and animals offered 3W silage consumed proportionately 0·18 more silage DM and produced 1·6 MJ/day more milk energy output than those offered 3UnW. The total ration digesibility and food utilization data showed the animals given the 3W silage consumed 13·5 MJ more metabolizable energy (ME) per day than those offered the 3UnW silage and were less efficient at converting the ME available for production into milk energy output than those given the 3UnW silage (efficiencies were 0·58 and 0·53 for 3UnW and 3W silages respectively).There were no differences between the digestibilities of the spring (lUnW) and autumn (3UnW) silages with the concentrations of digestible organic matter in the dry matter (DM) being 650 and 648 g/kg respectively. However, animals offered lUnW silage consumed proportionately 0·12 more DM and produced 1·05 kg/day more fat-corrected milk than those given 3UnW silage. The food utilization data indicated that this milk production difference could be accounted for by the higher ME intake on lUnW and that the efficiencies of conversion of ME available for production to milk energy output were similar with both seasons of harvests (efficiencies were 0·57 and 0·58 for lUnW and 3UnW respectively).Increasing the crude protein concentration of the supplement from 160 to 210 g/kg increased silage DM intake, milk yield and milk energy output by 0·2 kg, 0·66 kg and 1·9 MJ/day respectively with the response being greatest with lUnW and least with 3UnW silage. Increasing the fat concentration of the supplement depressed silage DM intake but increased milk yield by 0·53 kg/day.The effects of the treatments on total diet digestibility, energy and nitrogen utilization, and the volatile fatty acid concentrations of rumen fluid are also given.


1984 ◽  
Vol 9 ◽  
pp. 109-109
Author(s):  
D. J. Roberts ◽  
H. R. Ferns

The milk composition responses in five feeding trials were as follows.1. A study of silage quality showed that the fat content was lower (39.9 v. 43.1 g/kg, s.e. of difference 1.00) and the protein content was higher (35.0 v. 33.7 g/kg, s.e. of difference 0.48) with silage cut three times per season compared with silage cut twice per season.2. Silage offered as a buffer food overnight in the early part of the grazing season reduced milk yield (18.9 v. 19.9 kg/day, s.e. of difference 0.26) and increased fat content (39.4 v. 35.6 g/kg, s.e. of difference 0.50) when compared with grazing only. Silage offered in the late grazing season did not affect milk yield but increased fat content(44.1 v. 41.3 g/kg, s.e. of difference 0.94). There was no significant effect on protein content.3. A concentrate containing 18 g crude protein/kg was offered at rates of 0.30, 0.375 and 0.45 kg/kg milk plus silage ad libitum. The fat contents were 38.0, 38.6 and 36.1 g/kg and the protein contents 30.3, 31.2 and 32.1 g/kg, respectively.4. In two experiments comparing flat-rate concentrate feeding with feeding according to yield, no significant differences were found in milk yield, fat and protein contents.5. In a study of body condition at calving, cows calving at score 2 had milk fat contents similar to cows calving at score 3 but there were differences in the fatty acid composition of the milks. The cows calving at score 2 produced milk with a higher protein content than those at score 3 (32.8 v. 30.7 g/kg, s.e. of difference 0.85).


1973 ◽  
Vol 17 (1) ◽  
pp. 65-74 ◽  
Author(s):  
J. F. O'Grady ◽  
F. W. H. Elsley ◽  
R. M. MacPherson ◽  
I. McDonald

SUMMARYTwenty-four gilts were used at each of two centres in an experiment designed to examine the effects of dietary energy intake during lactation on yield and composition of sows' milk and the growth of their litters. Gestation feed intake was standardized at 2 kg per day supplying 6·28 Meal digestible energy (DE) and 280 g crude protein. The energy levels fed during lactation ranged from 12·2 to 18·25 Meal DE per day for gilts, 12·9 to 19·6 Meal DE per day for second parity and from 13·2 to 20·25 Meal DE per day for third parity sows. Daily crude protein intake and amino acid balance ofthe protein were kept constant.In the first lactation milk yield and composition and growth of litters were not influenced by dietary energy intake. In the second lactation milk yield was depressed by lower energy intakes and this was reflected in litter weights at 21 though not at 42 days. In the third lactation lower energy intakes seriously depressed milk yield and daily output of milk nutrients. On the lowest level of energy, milk yield was 32% lower at day 24 and 20% lower at day 41 of lactation than on the highest energy level. The corresponding depressions in litter weights were 17·2 and 13·5% at 21 and 42 days respectively.


1958 ◽  
Vol 38 (2) ◽  
pp. 160-170 ◽  
Author(s):  
M. A. MacDonald ◽  
J. M. Bell

Changes in milk yield and milk composition from mature Holstein-Friesian cows managed under low fluctuating environmental temperatures have been presented. The experiment conducted at the University of Saskatchewan, Saskatoon, lasted for 106 days during the winter of 1956–57. Loafing barn temperatures, measured continuously in degree-hours per day (d-h/day) ranged from 110 to 1202 and daily minimum ambient air temperature (DMAAT) varied from −5° to 38°F.As temperature decreased below 25°F., daily yield of milk decreased significantly. Milk yield was unaffected by d-h/day at mean temperatures over 25°F. (600 d-h/day) and on days colder than 600 d-h/day the temperature effect on milk yield was curvilinear. The rate of decline in milk yield (pounds) was four times greater on days when DMAAT was below 10°F. than on days when DMAAT was above 10°F. While DMAAT had a significant effect on milk total-solids percentage and a highly significant negative effect on crude protein yield, the effect of d-h/day on these two factors was not significant. Neither DMAAT nor d-h/day had a significant effect on butterfat yield and percentage, fat-corrected milk yield, total-solids yield, solids-not-fat yield and percentage, or crude protein percentage.Stage of lactation had a significant effect on all characteristics studied except butterfat percentage.Under conditions of declining lactation and a high, variable plane of nutrition, cows that had been subjected to gradually cooling variable low temperatures were influenced by low daily minimum temperatures (DMAAT) to a greater degree than low mean daily temperatures (d-h/day).


2021 ◽  
Author(s):  
Jialin Wei ◽  
Mengying Dou ◽  
Shuai Liu ◽  
Bichuan Yan ◽  
Cuiyu Li ◽  
...  

Abstract Background: Because of disadvantages of excessive dietary crude protein (CP), decreasing dietary CP of dairy cows has attracted the worldwide attention. Rumen protected methionine (RPM) supplementation can allow lower CP diets and is beneficial to milk production performance, N efficiency of cows and environment. The aim of this study was to evaluate the effects of reducing dietary CP and supplementing RPM on production, digestibility of nutrients, blood parameters, ruminal metabolites and economic effectiveness in lactating Holstein dairy cows. Results: A total of 96 lactating cows (63 ± 25 d in milk; 34.4 ± 5.74 kg/d of milk production; mean ± SD) were randomly assigned to 1 of 2 treatments: diet containing 17.3% CP without RPM (control group; CON; n = 49); diet containing 16.4% CP with supplementing 15.0 g/d of RPM (treatment group; RPM; n = 47). No effect was observed of reducing dietary CP on milk yield and milk composition. The apparent digestibility of nutrients was similar between treatments. The results related to blood showed that cows in RPM group exhibited lower concentration of blood urea nitrogen than that in CON group (P < 0.001). Moreover, there were no differences between treatments on concentrations of aspartate transaminase, alanine transaminase, alkaline phosphatase, globulin and albumin. In ruminal metabolites, microbial crude protein (MCP) of dairy cows in RPM group was higher compared with CON group (P = 0.006). Ruminal volatile fatty acid (VFA) contents were not changed by treatments except that the concentrations of butyrate and isovalerate of RPM group were higher than that of CON group at 2 h after feeding (P < 0.05). In addition, supplying the diet of 16.4% CP with RPM supplementation to cows could reduce feeding cost by 0.5 $/d per cow and boost net profits. Conclusions: Lower dietary CP with RPM supplementation did not limit milk yield, milk composition and apparent digestibility of nutrients, and could improve nitrogen utilization of dairy cows and synthesis of MCP in rumen, change VFA production at 2 h after feeding, as well as boost the economic benefits of the dairy farms.


2017 ◽  
Vol 57 (4) ◽  
pp. 656 ◽  
Author(s):  
C. Muñoz ◽  
D. A. Wills ◽  
T. Yan

Twenty early lactation dairy cows were used to evaluate the effects of the dietary addition of an active dried yeast product at two levels of concentrate on productive performance, nutrient digestibility, methane (CH4) emissions and energy and nitrogen utilisation. This study was a replicated 4 × 4 Latin square design with a two (concentrate level) × two (yeast supplement) factorial treatment arrangement, with four periods (6 week/period) and a 3-week interval between each period. Cows were offered grass silage-based diets consisting of two levels of concentrate (300 and 600 g/kg), with or without supplement of 0.5 g/day of an active dry yeast (Saccharomyces cerevisiae strain) with a specification of 2 × 1010 cfu/g. Feed dry matter intake, milk yield, milk composition, bodyweight and body condition score were similar between yeast treatments at both concentrate levels. Nutrient digestibility was not affected by yeast supplementation. Energy intake and faecal, urinary, CH4 and milk energy outputs were also not affected by yeast supplementation. Yeast supplementation had no effects on energy partitioning but tended to increase heat production and decreased energy retention. Yeast supplementation at two levels of concentrate had no effect on total CH4 emissions, but tended to increase CH4 per unit of feed intake and CH4 energy output per unit of gross energy intake. There were no effects of yeast supplementation on CH4 per unit of milk yield. Yeast supplementation had no effect on any variable of nitrogen intake, output or utilisation. Overall, the dietary addition of an active dried yeast product at two concentrate feeding levels had no effects on feed intake, milk production, milk composition, nutrient digestibility, or nitrogen utilisation efficiency and only tended to increase heat production, CH4 per unit of feed intake and CH4 energy output per unit of gross energy intake in lactating dairy cows.


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