scholarly journals INFLUENCE OF DAIRY COWS FEEDING ON THE CONTENT OF UREA IN MILK

2021 ◽  
Author(s):  
Сауле Бостанова
Keyword(s):  
Health Status ◽  
Dairy Cows ◽  
Milk Fat ◽  
Crude Protein ◽  
Dairy Farm ◽  
State Standards ◽  
Holstein Cows ◽  
Milk Productivity ◽  
Modern Equipment ◽  
Main Components

This article presents the results of the level of feeding and the health status of dairy cows in a commercial dairy farm on the content of the main components in milk (fat, protein, urea). The aim of the research was to study the milk productivity and composition of milk of cows, to analyze the level of feeding and the content of basic nutrients in the diet of the farm. The object of the research was Holstein cows in the amount of 483 heads of Aina Dairy Farm LLP. The studies were carried out according to generally accepted zootechnical methods using modern equipment for conducting analyzes and interstate and state standards. An increase in the norm of the content of crude protein in the diets of dairy cows to 17.4% DM led to an increase in the content of urea by 2.3% in comparison with the norm in the milk of cows of the first group, while the content of urea in the milk of the second group remained within the limits valid values.

scholarly journals Indicators of full value feeding rations for dairy cows

2022 ◽  
Vol 82 ◽  
Author(s):  
S. Bostanova ◽  
D. Aitmukhanbetov ◽  
K. Bayazitova ◽  
D. Zhantleuov ◽  
Y. Il
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Crude Protein ◽  
Dairy Farm ◽  
State Standards ◽  
Milk Productivity ◽  
Genetic Potential ◽  
Holstein Friesian ◽  
Dining Room ◽  
Main Components

Abstract This article presents the results of the level of feeding and the health status of dairy cows in a commercial dairy farm on the content of the main components in milk (fat, protein, urea). The aim of the research was to study the milk productivity and composition of milk of cows, to analyze the level of feeding and the content of basic nutrients in the diet of the farm. The farm breeds purebred Holstein cattle with a high genetic potential for productivity. The milking herd was formed in 2009 on the basis of 600 heads of Holstein-Friesian heifers imported from Hungary, as well as 65 heads of Holsteinized heifers of Ukrainian selection from Ukraine in 2015. Today the livestock numbers about 1,500 head of cattle, of which there are about 900 breeders. On the territory of the farm there are: 3 cowsheds for keeping cows, an insemination room, a milking parlor with a parallel installation of the Delaval company, in which 48 cows are milked for one milking, the ABK, where the manager's office, livestock technician, accounting is located, and a mini-hotel with dining room and lounges. Dairy bases are equipped with auto-drinkers, ventilation, plumbing, electric lighting, manure removal mechanisms, and a milking installation. The object of the research was Holstein cows in the amount of 483 heads of Aina Dairy Farm LLP. The studies were carried out according to generally accepted zootechnical methods using modern equipment for conducting analyzes and interstate and state standards. The research results showed that the milk productivity of cows averaged 19.5 kg per day, the fat content 4.3%, the protein 3.9%, the number of somatic cells 230.5 thousand units / ml, urea 45.3 mg / 100 ml respectively. Analyzing the level of urea in milk can suggest a high crude protein content in the diet. The ration of feeding dairy cows on the farm is concentrate-silage-haylage and there is an excess of dry matter by 16.2%, crude protein by 9.8%, starch by 29.4%, respectively.

scholarly journals DURATION AND EFFECTIVENESS OF LIFETIME USE OF DAIRY COWS DEPENDENDING ON THEIR FATHER'S COUNTRY ORIGIN

2017 ◽  
Vol 54 ◽  
pp. 19-29 ◽  
Author(s):  
N. P. Babik ◽  
Ye. I. Fedorovych ◽  
V. V. Fedorovych
Keyword(s):  
Life Expectancy ◽  
The Netherlands ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Milk Fat ◽  
Country Of Origin ◽  
Holstein Cows ◽  
Milk Productivity ◽  
Black And White ◽  
Dairy Breed

Productive longevity is a very important feature, which is determined by a combination of genotype factors in specific environments. It is known that in recent decades to improve of productive qualities of domestic dairy cattle, the Holstein breeders of different breeds are used. Such measures, although allowed to increase the milk productivity of cows significantly, however, led to reduction in the duration of their productive use. Therefore, the purpose of our research was to study the duration and effectiveness of lifetime use of dairy cows, depending on the country of origin of their father. The research was conducted on animals of Holstein (n = 2902), Ukrainian Black-and-White (n = 14876) and Ukrainian Red-and-White (n = 2176) breeding in various regions of Ukraine. It was established that the controllable number of Holstein cows came from 116 bulls from five different countries. Cows originated from the bulls of Hungarian selection had the longest life and lactation. Cows that came from Canadian bulls had the best life-long yields and life-long number of milk fat. Cows from French bulls were characterized by the worst indicators of productive longevity. Among the descendants of the German bulls, the daughters of the following bulls: Lord 661287, Trend 2761400782690, Bg. Rodeo 27642626161 and Ingo 27677179331, American selection – daughters of B. Astronomer 2160438 and Bob Hubby 2109267, Canadian – daughters of Rock 373840409 and H. R. Artist 6284191, Hungarian – daughters of V.Vilmos 3101733688 and E.Samba 3035115974 and French – daughters of Brico 5794006324 had the best indicators of the duration and efficiency of lifelong use. The studied population of cows of Ukrainian Black-and-White dairy breed came from 167 bulls from eight countries. The largest number of daughters was obtained from domestic bulls (34.6%) and German (29.5%) selection. However, cows of Russian selection had the highest rates of longevity, productive use, lactation, the number of lactations per life, life expectancy and lifetime of milk fat. Daughter Valentina 373840175, Matadora 373840109, Piclenda 373880102 and Tigris 373880127 were lactured more than 4 lactations and had lifelong yield of over 25,000 kg, among the descendants of Russian bulls. Of the descendants of the domestic selection the daughters of the Abrykos 5806 lactated in an average of 6.2 lactation, and their lifetime yields were 38,401 kg. By the number of lactations per life and life-long yields of the daughters of the German bulls, the leader was Presbyter 27621490100, the American – Bob Hubby 2109267 and T. D. Fiasco 1709950, the Canadian – B. Goldgate 6387868 and B. Regensy 394223, the Netherlands – G. Tristan 3021652032 and Baneliai 243931215, Hungarian – E. Samba 3035115974 and P. Selvichar 3023006464. The controlled population of cows of Ukrainian Red-and-White dairy breed came from 69 bulls from five countries. More than 50% of cows of this breed are derived from bulls of German selection. However, the longest duration of productive use and the greatest lifelong yields had daughters of bulls from Canada and Ukrainian selection. Among the descendants of the domestic bulls, according to the indicators of lifetime productivity, the daughters of Khlor 2052 differ markedly. They lacted in average 7.7 lactations, and lifetime longevity was 41,000 kg. Among the descendants of Canadian bulls, the best of their productive use and their lifelong yields had daughters of V. Texel 393522, V.N.Dan 5510544 and Inhibitor 402151, German – Roman 660886883 and Tumpi 112367468, and American – Addikshn 17143107. The influence of the father's country origin on the longevity, productive use, lactation and the number of lactations per life, depending on the breed and the indicator, was within the range of 1.4–17.1, on the indicators of lifetime productivity – within 1.5–9.7%, and the influence of the father on these indicators was, respectively, 9.9–19.9 and 11.4–29.3%.

COMPARATIVE DESCRIPTION OF MILK PRODUCTIVITY OF COWS UKRAINIAN RED-AND-WHITE DAIRY CATTLE AND UKRAINIAN BLACK-AND-WHITE DAIRY CATTLE AND HOLSTEIN BREEDS IN SERF «OLEKSANDRIVSKE»

2016 ◽  
Vol 52 ◽  
pp. 6-12 ◽  
Author(s):  
M. V. Gladiy ◽  
G. S. Kovalenko ◽  
S. V. Priyma ◽  
G. A. Holyosa ◽  
A. V. Tuchyk ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Dairy Cows ◽  
Milk Yield ◽  
Fat Content ◽  
Holstein Cows ◽  
Milk Productivity ◽  
Black And White ◽  
The Third ◽  
Fat Yield ◽  
Selection Of

The main goal of dairy breeds selection should be improving breeding and productive qualities of animals under modern conditions. The majority of farms, using native breeds to produce milk, has created optimal conditions for keeping and feeding, selection and matching, growing of replacements etc. Further improvement of created native dairy breeds for economically useful traits occurs at total use of purebred Holstein bulls (semen) of foreign selection. In order to realistically assess milk productivity (milk yield, fat content in milk and fat yield) of Ukrainian Black-and-White and Red-and-White Dairy cows should be conducted a comparative analysis of Holstein cows under the same conditions of feeding and keeping. It was established that Ukrainian Red-and-White Dairy cows were characterized by the highest milk yields for 305 days of all lactations, taken into account, the among three investigated breeds. Their milk yield during the first lactation was 5933 kg of milk, during the second – 6393 kg, the third – 6391 kg and during higher lactation – 6650 kg. Ukrainian Black-and-White Dairy cows were second by milk yield (except for the second lactation), during the first lactation – 5932 kg of milk, the third – 6462 kg and higher – 6541 kg, and Holstein cows were third, during the first lactation – 5794 kg of milk, the second – 6381 kg, the third – 6335 kg and higher – 6469 kg. The fat content was almost the same and varied within 3.49-3.58% in milk of Ukrainian Red-and-White Dairy cattle, 3.50-3.60% in milk of Ukrainian Black-and-White Dairy cattle and 3.50-3.56% in Holsteins’ milk. The difference between the breeds was within 0.01-0.04%. All the investigated breeds had predominance in fat yield for three lactations over standards of these breeds: Ukrainian Red-and-White Dairy cows from 75.1 to 93.4 kg, Ukrainian Black-and-White Dairy cows – 75.1-89.0 kg respectively and Holstein cows – 41.9-60.2 kg. It was found different level of positive correlation between milk yield and fat yield in all the cases and high correlation (r = 0.604-0.921, P < 0.001) in five cases (41.7%) Negative correlation coefficients indicate that selection of animals to higher milk yield in the herd will decrease the second trait – fat content in milk. Positive and highly significant correlation between milk yield and fat yield indicates that selection of cows in the herd to higher milk yields will increase fat yield. It was revealed that bulls were among the factors impacted the milk productivity (milk yield, fat content, fat yield) of three investigated breeds. So, the force (η²x) of father’s impact on milk yield was15.4-47.9%, fat content – 22.0-43.4% and fat yield – 14.9-47.7% taking into account a lactation and a breed. The force of lines impact (η²x) was second; it was on milk yield 6.1-24.5%, fat content – 4.1-17.1 and fat yield – 5.8-23.5%. The force of breeds impact (η²x) was last; it was on milk yield 0.3-2.9%, fat content – 0.2-0.3% and fat yield – 0.6-2.7%. So, the comparative studies of milk productivity of Ukrainian Red-and-White and Black-and-White Dairy cattle with Holsteins indicate that under similar conditions of feeding and keeping, these native breeds can compete with Holstein cattle. The milk yield for 305 days of higher lactation was 6650 kg of milk in Ukrainian Red-and-White Dairy cows, 6541 kg in Ukrainian Black-and-White Dairy cows and 6469 kg in Holsteins. It was found the inverse correlation r = -0.025-0.316 between milk yield and fat content in milk in most cases. Selection and matching of animals in the herd should be carried out simultaneously on these traits. It was found positive repeatability of milk yields between the first and second, the third and higher lactations (rs = 0.036-0.741), indicating the reliability of forecasting increase in milk productivity during the next lactations in all herd. Bulls have the greatest impact (η²x) on milk productivity among the factors taken into account: milk yield – 15.4-47.9%, fat content in milk – 22.0-43.4% and fat yield – 14.9-47.7%.

scholarly journals Identification of Genomic Regions Associated with Concentrations of Milk Fat, Protein, Urea and Efficiency of Crude Protein Utilization in Grazing Dairy Cows

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 456
Author(s):  
Hewa Bahithige Pavithra Chathurangi Ariyarathne ◽  
Martin Correa-Luna ◽  
Hugh Thomas Blair ◽  
Dorian John Garrick ◽  
Nicolas Lopez-Villalobos
Keyword(s):  
Gene Ontology ◽  
New Zealand ◽  
Dairy Cows ◽  
Candidate Genes ◽  
Milk Fat ◽  
Crude Protein ◽  
Single Locus ◽  
Protein Utilization ◽  
Grazing Dairy Cows ◽  
Genomic Regions

The objective of this study was to identify genomic regions associated with milk fat percentage (FP), crude protein percentage (CPP), urea concentration (MU) and efficiency of crude protein utilization (ECPU: ratio between crude protein yield in milk and dietary crude protein intake) using grazing, mixed-breed, dairy cows in New Zealand. Phenotypes from 634 Holstein Friesian, Jersey or crossbred cows were obtained from two herds at Massey University. A subset of 490 of these cows was genotyped using Bovine Illumina 50K SNP-chips. Two genome-wise association approaches were used, a single-locus model fitted to data from 490 cows and a single-step Bayes C model fitted to data from all 634 cows. The single-locus analysis was performed with the Efficient Mixed-Model Association eXpedited model as implemented in the SVS package. Single nucleotide polymorphisms (SNPs) with genome-wide association p-values ≤ 1.11 × 10−6 were considered as putative quantitative trait loci (QTL). The Bayes C analysis was performed with the JWAS package and 1-Mb genomic windows containing SNPs that explained > 0.37% of the genetic variance were considered as putative QTL. Candidate genes within 100 kb from the identified SNPs in single-locus GWAS or the 1-Mb windows were identified using gene ontology, as implemented in the Ensembl Genome Browser. The genes detected in association with FP (MGST1, DGAT1, CEBPD, SLC52A2, GPAT4, and ACOX3) and CPP (DGAT1, CSN1S1, GOSR2, HERC6, and IGF1R) were identified as candidates. Gene ontology revealed six novel candidate genes (GMDS, E2F7, SIAH1, SLC24A4, LGMN, and ASS1) significantly associated with MU whose functions were in protein catabolism, urea cycle, ion transportation and N excretion. One novel candidate gene was identified in association with ECPU (MAP3K1) that is involved in post-transcriptional modification of proteins. The findings should be validated using a larger population of New Zealand grazing dairy cows.

scholarly journals Is rumenocentesis a safe technique to collect rumen fluid in dairy cows?

2018 ◽  
Vol 69 (3) ◽  
pp. 1135 ◽  
Author(s):  
N. PANOUSIS ◽  
G. KITKAS ◽  
G. E. VALERGAKIS
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Rumen Fluid ◽  
Small Diameter ◽  
Dairy Farm ◽  
Holstein Cows ◽  
Short Term ◽  
Safe Technique ◽  
Daily Milk Yield ◽  
Daily Milk

Subacute ruminal acidosis is a major issue in dairy cattle and a definite diagnosis is only established by measuring the rumen fluid pH, most credibly collected by rumenocentesis. However, due to its invasive nature, there is still some debate whether it is a safe method or poses risks for cows’ health and welfare. The aim of the study was to retrospectively evaluate the safety of rumenocentesis as a technique to obtain rumen fluid in dairy cows. Results were derived from 2 studies. In study 1, rumenocentesis was performed in 153 Holstein cows from 12 herds, once, between 10 and 90 days in milk (DIM). In study 2, 83 Holstein cows from a dairy farm were repeatedly subjected to rumenocentesisat 30, 90 and 150 DIM. From the 83 cows that were initially enrolled, 8 were culled before the end of the study for reasons irrelative to rumenocentesis; therefore, 236 rumenocenteses were actually performed in study 2 (3 times in 75 cows, twice in 3 cows and once in 5 cows). All cows were monitored for 10 days after rumenocentesis for presence of complications. In addition, daily milk yield was automatically recorded for each cow in study 2 to detect any possiblepost-rumenocentesis short-term reduction of milk yield. Minor only complications were recorded in 7 cases: in 4/153 (2.61%) and 3/236 (1.27%) rumenocenteses in studies 1 and 2, respectively. Small diameter abscesses in 6 cows (3 in study 1 and 3 in study 2) and a larger one in 1 cow in study 1 were observed. The 3 small abscesses in study 2 were all recorded after the 1st rumenocentesis, at DIM 30. All 7 cases were resolved spontaneously within two weeks. Moreover, short-term daily milk yield of study 2 cows was not affected by rumenocentesis. The conclusion is that rumenocentesis is a safe technique to collect small volume of rumen fluid for SARA diagnosis, which does not compromise cows’ health and welfare when appropriately performed.

scholarly journals Effects of Saccharomyces cerevisiae Addition in Dairy Cows Diets

2021 ◽  
Vol 78 (1) ◽  
pp. 18
Author(s):  
Marinela ENCULESCU
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Health Status ◽  
Dairy Cows ◽  
Milk Yield ◽  
Milk Fat ◽  
Control Group ◽  
Free Access ◽  
Alternative Source ◽  
Effective Measure ◽  
Experimental Group

The aim of this study was to evaluate the effects of fresh yeast (Saccharomyces cerevisiae) supplementation in the dairy cows’ diets on productive performances and health status. The study was carried out in the experimental farm of the Research and Development Institute for Bovine Balotești on 50 multiparous Romanian Black and Spotted dairy cows, randomly divided into two groups (N = 25 heads/group), according to age, milk yield, body weight and health status. The experimental group received 80 g Saccharomyces cerevisiae/head/day for one year. The groups were fed with the same diet and had free access to water and salt. Results were expressed as a mean (±Standard Deviation). The t-test was applied to obtain the significance of difference. Supplementation of the diet with Saccharomyces cerevisiae had a significant effect (P <0.001) on milk yield (20.71±1.65 l/head/day) for the experimental group comparing with the control group (18.22±1.81 l/head/day), and on milk protein and lactose (P <0.05). The addition of Saccharomyces cerevisiae in dairy cows’ diet did not improve the milk fat, hematological and biochemical/urine indicators in the experimental group (P >0.05). However, for alkaline phosphatase, differences at the end of the study have been observed (P <0.01). The beneficial effect of the yeast and yeast products in ruminants could be attributed to microbial activity by increasing the number of beneficial bacteria in the rumen of the animals. The use of Saccharomyces cerevisiae as an alternative source of economic protein, vitamins and minerals in dairy cows’ diet represents an effective measure to optimize animal productivity.

scholarly journals The effect of fat supplementation of concentrates on digestion and utilization of energy by productive dairy cows.

1981 ◽  
Vol 29 (2) ◽  
pp. 79-92 ◽  
Author(s):  
Y. van der Honing ◽  
B.J. Wieman ◽  
A. Steg ◽  
B. van Donselaar
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Crude Protein ◽  
Latin Square ◽  
Soya Bean ◽  
Metabolizable Energy ◽  
Simultaneous Reduction ◽  
Gross Energy ◽  
The One ◽  
Lipid Supplement

Two energy balance experiments each used 6 high-yielding dairy cows. In the first, a 3 X 3 Latin square with one replicate, rations were of 7 kg hay and 11 to 14 kg of concentrates having crude protein 251 g and gross energy 17.9 MJ/kg, given alone or with 5% tallow or 5% soya bean oil. Three weeks of adaptation were followed by 10 to 12 days when excreta were collected and gas exchange estimated. Digestibility and metabolizable energy of concentrates and hay were also assessed using wethers fed to maintenance only. Intakes of DM and digestibility of nutrients other than lipid did not differ among treatments with either sheep or cows. There were no apparent differences in rumen fermentation in the one cannulated cow used, and energy loss in urine was also unaffected. Lipid supplement reduced methane loss. Milk yield and milk energy were increased with tallow, with a simultaneous reduction of milk fat and percentage of protein. Soya bean oil reduced the percentage of milk fat and milk energy produced. The second trial, using similar animals and with similar management had a change-over design in which the concentrate was given alone or with 7% tallow. Results confirmed those of trial 1. The effect of level of feeding on the efficiency of utilization of energy is discussed. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Influence of the Amyrasol R-Z mineral lick briquette on biochemical parameters of blood in dairy cowsInfluence of the Amyrasol R-Z mineral lick briquette on biochemical parameters of blood in dairy cow

2020 ◽  
pp. 13-14
Author(s):  
Ayub Yu. Aliev ◽  
◽  
Karine A. Karpushchenko ◽  
Abdulgamid A. Aliev ◽  
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Biochemical Parameters ◽  
Fat Content ◽  
Control Group ◽  
Milk Productivity ◽  
Basic Diet ◽  
The Republic ◽  
Experimental Group ◽  
Mineral Lick

The data obtained as a result of the use of a mineral lick briquette Amirasol R-Z in the diets of dairy cows are analyzed in the article. Authors studied the influence of the mineral lick briquette Amirasol R-Z on the biochemical parameters and milk productivity of dairy cows. The experiments were carried out on dairy cows of the red steppe breed in the conditions of the plain zone of the Republic of Dagestan. Two groups of dairy cows were formed (10 heads in each). According to the scheme of the experiment, the control group received a basic diet, the experimental group received the basic diet and the mineral lick briquette Amirasol R-Z. Each cow of the experimental group was given individually one lick briquette in a dose of 4 kg during 90 days. Researches and data processing were carried out according to generally accepted methods. Blood was taken from the experimental animals from the jugular vein for laboratory studies at the end of the experiment. The milk productivity and fat content of milk were taken into account by carrying out monthly control milk yields. At the same time, the positive effect of a lick briquette on the biochemical parameters of blood has been proven: reserve alkalinity, glucose, macro- and microelements, the activity of the copper-containing enzyme ceruloplasmin and milk productivity. A significant increase in the blood of glucose concentration by 12.93% in the cows of the experimental group, the level of reserve alkalinity by 17.66%, the concentration of macroelements and microelements, milk productivity by 5.7%, milk fat by 2.77% compared with the control group. The use of the mineral lick briquette Amirasol R-Z in the diets of dairy cows helps to prevent macro- and microelementoses, increase milk productivity, milk fat content, nonspecific immunity and obtain of healthy calves.

scholarly journals A study of the incidence of milk fever in Jersey and Holstein cows at a dairy farm in Beatrice, Zimbabwe

2017 ◽  
Vol 88 ◽  
Author(s):  
Bernard Chiwome ◽  
Erick Kandiwa ◽  
Borden Mushonga ◽  
Shepherd Sajeni ◽  
Gervais Habarugira
Keyword(s):  
Prospective Study ◽  
Dairy Cows ◽  
Milk Production ◽  
Dairy Farm ◽  
Holstein Cows ◽  
Milk Fever ◽  
Significant Difference ◽  
Jersey Cows

A 3-year prospective study investigated the incidence of milk fever in Jersey and Holstein cows at a commercial dairy farm in Beatrice, Zimbabwe. The overall incidence of milk fever at the farm was 7.98%. Incidence of milk fever in Jerseys (14.78%) was significantly higher (p < 0.05) than that in Holsteins (4.82%). Incidence of milk fever in Jerseys beyond their fourth parity (24.85%) was significantly higher (p < 0.05) than that in Jerseys in their second (5.90%), third (6.49%) and fourth (8.73%) parities. Incidence of milk fever in Holsteins beyond their fourth parity (8.29%) was significantly higher (p < 0.05) than that in Holsteins in their second (1.43%), third (1.82%) and fourth (2.91%) parities. No significant difference existed in milk fever incidences between the second, third and fourth parities in either Jersey or Holstein cows. Incidence of milk fever in Jersey cows producing over 6114 litres per 305-day lactation (27.07%) was significantly higher than that in Jerseys producing less than 6114 litres of milk per 305-day lactation (p < 0.05). Incidence of milk fever in Holsteins producing more than 9149 litres per 305-day lactation (10.49%) was significantly higher than that in Holsteins producing less than 9149 litres of milk per 305-day lactation (p < 0.05). No significant difference existed between incidences of milk fever between the first, second and third quartile producers (p > 0.05) in either Jersey or Holstein cows. This study confirms that the risk of developing milk fever is higher in Jerseys and also increases with increasing parity and higher levels of milk production in both breeds, thus advocating for special considerations when dairy cows fit these criteria.

scholarly journals PROTEIN LEVELS IN GRASS SILAGE-BASED TOTAL MIXED RATIONS FOR DAIRY COWS IN MIDLACTATION

1984 ◽  
Vol 64 (2) ◽  
pp. 435-442 ◽  
Author(s):  
P. L. BURGESS ◽  
J. W. G. NICHOLSON
Keyword(s):  
Dairy Cows ◽  
Protein Level ◽  
Milk Fat ◽  
Crude Protein ◽  
Dry Matter ◽  
Ammonia Nitrogen ◽  
Plasma Urea ◽  
Protein Levels ◽  
Grass Silage ◽  
Nitrogen Intake

Total mixed rations containing three levels of crude protein (10, 13 and 16%) were fed ad libitum to a total of 48 cows in midlactation in two experiments. Rations were composed of 60% wilted timothy silage and 40% concentrates on a dry matter basis. Supplemental protein was supplied as soybean meal. Daily nitrogen intake per cow averaged 263, 377 and 510 g in exp. 1, and 305, 435 and 509 g in exp. 2 for the three rations, respectively. Cows fed rations containing 10% crude protein consumed less (P < 0.05) total dry matter and lost more (P < 0.01) body weight than cows fed rations with either 13 or 16% crude protein. Milk production was not affected by protein level in exp. 1 but in exp. 2, 10% crude protein decreased (P < 0.01) actual milk and 4% fat corrected milk yields. Milk fat and protein percentages tended to increase with increasing dietary protein level. Rumen acetate tended to decline while propionate increased (P < 0.05) at higher crude protein levels. Rumen ammonia nitrogen and plasma urea nitrogen levels were closely related to nitrogen intake. Key words: Dairy cows, grass silage, protein, solubility

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