DDGS Protein Value

Protein value of DDGS: A complex issue

German researchers looked at the effects of raw material use and production process on the quality of distillers dried grains with solubles (DDGS), a by-product of ethanol production from cereal grains.

Distillers dried grains with solubles is used as a protein source for production animals. Like crude protein (CP) content, degradability and digestibility of CP and amino acids (AA) are predetermined by the raw material grain, but also affected by the production process to a considerable degree. A review, composed by researchers from the University of Bonn in Germany and in press for the Journal Animal Feed Science and Technology, highlights steps of the production process potentially affecting the protein value of DDGS.

Effects of feed processing steps

Heat influence during drying of this by-product is most discussed. During heating, AA can undergo a series of chemical reactions resulting in reduced digestibility or destruction of AA. To evaluate the heat influence on DDGS protein quality, measuring color variables, acid detergent insoluble N and AA content have been applied, although all of these methods have some limitations. Besides drying, further processing steps potentially affecting the protein value of DDGS are: high temperature application prior to drying or blending of product streams. Yeast protein contributes to DDGS protein but estimations of the actual amount differ considerably. Although the outlined effects and their underlying principles are known, their systematic investigation is impeded by the complex nature of the production process.

Production process is complex

In this review, several possible effects of the ethanol production process on DDGS protein value have been lined out. The underlying chemical, biological and technological principles of these effects are known. However, the production process is complex, effects may be additive or interactive and it is therefore difficult to quantify the outcome regarding protein value on a general basis. For example, the course of the Maillard reaction is not only influenced by temperature, but also duration, water activity and pH (Mauron, 1990). Targeted research to quantify the influence of single processing variables on DDGS protein value may probably only be possible on a laboratory scale. Regular monitoring of DDGS protein value by producers and users may be necessary, however, this is not as easy as evaluation of chemical composition.

Greater variability, better standardisation

The researchers address that ethanol production process is constantly evolving and new techniques are introduced, like raw starch hydrolysis as discussed above and fractionation of cereal grain or distillers grains, e.g. to remove fibre or oil (Berger and Singh, 2010; Rosentrater et al., 2012). This leads to diversification of distillers by-products and could lead to greater variability in chemical composition and protein value of DDGS (Martinez-Amezcua et al., 2007). On the other hand, it may contribute to better standardization and closely defined products within companies and plants.

 

Source: C. Böttger et al, https://www.allaboutfeed.net/New-Proteins/Articles/2018/9/Protein-value-of-DDGS-A-complex-issue-329233E/?cmpid=NLC|allboutfeed|2018-09-03|Protein_value_of_DDGS:_A_complex_issue

DDGS Protein Value2019-09-21T05:38:44-01:00

Mycotoxin Sampling in Silos

Sampling is key in mycotoxin control. A team of Brazilian researchers put 2 different sampling methods to the test in maize and wheat silos.

The storage of cereals in vertical silos, whether or not equipped with temperature control and aeration, is a common practice throughout the world to preserve grain quality and safety. However, it is still possible that the cereals become contaminated with mycotoxins. The problem is that mycotoxin contamination of stored cereals often occurs in a highly heterogeneous manner. It is therefore key to use representative sampling to minimize analytical errors.

The objective of this study, in press for the World Mycotoxin Journal, was to compare mycotoxin analysis in stored maize and wheat using 2 sampling processes. Samples were obtained from 4 maize silos and 2 wheat silos. Samples of maize and wheat grains stored in silos, containing approximately 1000 tons of maize or wheat in each silo, were collected. The silos structures were identical (Ø=12 m, wall height =12.5 m and roof height =3 m), but the maize silos had temperature control and automated aeration while wheat silos had only manual aeration control.

For sampling, a pneumatic probe was introduced in the center and at the 4 central points of each quadrant, from the top to the bottom of the silo (12 m). In sampling process B, a single large sample that spanned the height of the silo was taken, whereas for sampling process A, the sample was split into 3 (upper third, middle third and lower third of the silo). The pneumatic probe was introduced 3 times at 5 points in each silo to give 45 global samples for process A and 15 global samples for process B, totaling 240 global maize samples and 120 global wheat samples in this study.

Results of the mycotoxin detection tests

LC-MS/MS was used for analysis of aflatoxins (AF), fumonisins (FB), zearalenone (ZEA) and deoxynivalenol (DON) in maize and DON and ZEA in wheat. Sampling procedures were compared with respect to the variability of the collected data. AF, FB, ZEA and DON were detected in 77.5, 100.0, 56.7 and 0.0% of the maize samples, respectively, and the mean concentration differed significantly between silos. In wheat, 100.0 and 97.5% of the samples were contaminated with DON and ZEA, respectively, and there was no significantly difference in mean concentration between silos.

Difference between sampling methods

Mycotoxin analysis performed in maize samples obtained using A and B sampling procedures exhibited the same variability. For wheat samples, process A provided lower variability for DON detection than process B. However, considering the silo as a whole, the 2 sampling procedures yielded samples that were similarly representative. The A or B sampling processes are both applicable in practice by the industry and may increase confidence in purchasing, sales and grain destination, increasing security in commercial transactions and adding value to stored grain.

Source: World Mycotoxin Journal, https://www.allaboutfeed.net/Mycotoxins/Articles/2018/8/   Mycotoxin-sampling-in-silos-2-methods-tested-326478E/?cmpid=NLC|allaboutfeed|2018-08-27|Mycotoxin_sampling_in_silos:_2_methods_tested

Mycotoxin Sampling in Silos2019-09-21T05:38:45-01:00

Nutrition is key for transition cows (Part 02)

Importance of protein and amino acids in nutrition

Although less well explored than metabolisable energy (ME) balance, metabolisable protein (MP) balance is also important for successful reproduction. In this review study, improved early-lactation MP balance tended to increase the proportion pregnant. Increasing crude protein (CP) intake may increase nutrient loss via increased milk production and have negative effects on fertility, in association with higher urea nitrogen concentrations in blood. Increasing CP content of the diet does not necessarily increase MP availability, but decreasing the degradability of protein or increasing the fermentability of the diet may be more effective in increasing MP availability. The review also highlights that alterations in dietary protein may not simply affect MP balance, but also specific amino acids (AA) composition and supply of metabolisable AA. Specific roles for AA in reproductive performance are not well defined. Lysine and methionine have been suggested to be the most co-limiting AA for production, and supplementation of these may increase milk yield, but results are inconsistent. Supplementation of lactating cows with rumen-protected methionine or lysine has had positive or negligible effects on reproductive outcomes.

Positive effects of fatty acids

Microbial lipolysis and biohydrogenation in the rumen ensure that intake of fatty acids and those available for absorption in the duodenum differ; hence, these issues were explored separately. Fats not only provide an energy source but also are essential precursors for steroid hormones, and the beneficial effects of fat have been observed independently of the provision of energy. The researchers of this review noted that intakes of many of the fats (C14:0, C16:1, C18:0, C18:1 trans, C18:1 cis, and other, g/d) were uni-variably associated with an increased proportion of cows pregnant. No association was found between C18:3 identified with the proportion of cows pregnant, but fatty acids present in fish oil, docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid are included in the other fatty acids associated with the proportion of cows pregnant.

Role of carbohydrates

Carbohydrates are important sources of energy for cows, as well as for rumen microorganisms and generally increase the efficiency of protein utilisation and microbial protein production. However, increased concentrations of rapidly fermentable carbohydrates can increase the risk of acidosis. The type of carbohydrate also influences the risk of acidosis, with sugars posing a greater risk than starches. Consequently, carbohydrates have positive and negative effects on fertility. The positive associations of starch percentage and intake (kg/d), possibly because of a slower fermentation rate than sugars, and negative associations of soluble fibre and sugar percentage and intake (kg/d) with proportion pregnant were identified in uni-variable analyses. The review also mentioned that a negative association was found between increased CPM-estimated physically effective NDF intake (kg/d) and proportion pregnant in the uni-variable analysis. The only variable that remained in the multivariable models was the effect of sugar intake (kg/d), which was negatively associated with the proportion of cows pregnant. Ruminal acidosis may decrease fertility by reducing feed intake, producing a metabolic acidosis leading to detrimental alteration of uterine environment, stimulating inflammation that induces prostaglandin release, and resulting in luteolysis in a process analogous to that of mastitis.

Conclusions

This study highlights several important findings for future research on the effects of transition nutrition on fertility. It confirms that nutritional management of cows during the transition period can have substantial effects on reproductive success, and this finding is consistent with previous meta-analytical studies in this area. Overall, this study confirmed earlier findings that excessive protein intake can impair fertility, but that a positive MP balance is consistent with better fertility. However, it may be necessary to increase protein intake when feeding fats, and other work suggests a need to control the MP balance before calving. The role of specific metabolisable AA needs further study. This study also, critically, identified potential effects of specific carbohydrate fractions, especially sugar (kg/d), starch (kg/d), and physically effective NDF (kg/d) on reproductive outcomes.

Source:

This article is a short summary of the original paper: Effects of nutrition on the fertility of lactating dairy cattle, by R.M. Rodney, P. Celi, K. Breinhild, J.E.P. Santos and I.J. Lean, published in the Journal of Dairy Science, Volume 101, Issue 6.

Nutrition is key for transition cows (Part 02)2019-09-21T05:38:48-01:00

Nutrition is key for transition cows (Part 01)

Nutrition is key for transition cows

Nutritional management of cows during the transition period can have substantial effects on reproductive success. This was concluded from a large literature review.

Poor reproductive performance of lactating dairy cattle is a complex disorder that reflects associations with intensification of production and increased milk production. However, it is difficult to determine a causal basis for the decrease in fertility, as genetics and environment have changed markedly over the last decades. Nutritional influences on fertility have been examined and frequently reviewed, but difficulties and inconsistencies in study design occur. Studies must have large numbers of experimental units to identify biologically and economically important differences in proportion of cows pregnant. Nutritional influences during the transition period may be of particular importance, but it is clear that the effect of diet on fertility during this period is complex and multifactorial. The objective of the current study was to use carefully described dietary information from the available literature to explore the effects of the diet during the transition period on measures of pregnancy and calving to pregnancy interval as well as identifying factors that may explain variation in these responses. This research looked at 118 diets contained within 39 experiments to see what the effects on nutritional interventions fed during the early postpartum period.

Higher milk output, lower fertility

The extensive literature has observed that cows with greater milk production generally have poorer fertility, and that genetic selection for increased production can reduce fertility. Whereas genetic differences were not examined in this data set, the researchers identified associations between increased milk fat (kg/d) and protein production (kg/d) with reductions in the proportion pregnant, actual milk yield (kg/d), and milk protein yield (100 g/d) with longer calving to pregnancy interval. They also found that protein yield in very early lactation (first 3 weeks of lactation) was positively associated with the proportion of first services that resulted in pregnancy, and others identified positive associations between milk protein percentage and improved reproductive performance. These findings, overall, highlight possible differences between experiments conducted at the level of the individual and those at the group level. As milk protein production increases in a group of cows, it may be expected that nutrient intakes will need to be more closely aligned with nutrient losses, whereas the individual within the herd with greater production may have better phenotypic adaptation to the environment allowing greater milk protein yield and percentage.

Focus on nutrient balance and BCS

The availability of nutrients that can be allocated to reproduction is not just determined by immediate diet (i.e. the immediate intake of nutrients as dry matter intake (DMI)), but also by endogenous body tissue reserves, reflected in labile body weight (BW) and body condition score (BCS). Hence, DMI before and after calving is a key determinant of exogenous nutrient availability. The irreversible loss of nutrients in milk production and use of nutrients for maintenance and growth diminishes the nutrient pool available for reproduction. The difference between dietary intake and expenditure determines the nutrient balance, and if a negative balance occurs endogenous reserves are depleted. Many studies have examined the effects of estimated negative energy balance on fertility. The length and severity of a negative energy balance at the onset of lactation is largely determined by DMI around calving and milk yield. Estimated energy balance (MJ/d) was, as anticipated, positively associated with improved proportion pregnant and shorter calving to pregnancy interval. A better energy balance during the first 3 to 4 weeks of lactation reduces the interval to first ovulation and increases the probability of pregnancy at the following breeding. Excessively low or high BCS at calving, or extreme losses of BW or BCS in early lactation, are usually associated with impaired reproductive outcomes.

Source:

This article is a short summary of the original paper: Effects of nutrition on the fertility of lactating dairy cattle, by R.M. Rodney, P. Celi, K. Breinhild, J.E.P. Santos and I.J. Lean, published in the Journal of Dairy Science, Volume 101, Issue 6.

Nutrition is key for transition cows (Part 01)2019-09-21T05:38:48-01:00

Carbon Farming (Part 02)

Carbon farming: reducing methane emissions from cattle using feed additives

Feed additives or supplements offer one approach to reduce methane emissions from ruminant livestock. Livestock produce significant amounts of methane as part of their normal digestive processes. Some feed additives can inhibit the microorganisms that produce methane in the rumen and subsequently reduce methane emissions.

How feed additives work

Methane-reducing feed additives and supplements inhibit methanogens in the rumen, and subsequently reduce enteric methane emissions.

Methane-reducing feed additives and supplements are most effective when grain, hay or silage is added to the diet, especially in beef feedlots and dairies.

What are methane-reducing feed additives or supplements?

Methane-reducing feed additives and supplements can be:

  • synthetic chemicals
  • natural supplements and compounds, such as tannins and seaweed
  • fats and oils

Synthetic chemicals, such as antibiotics, are sometimes used to improve the efficiency of feed conversion in cattle, although it is not a recommended practice to use these additives to reduce methane emissions. There are legislative restrictions and human health concerns about using antibiotics as growth promotants in livestock.

There is potential for natural compounds and materials to reduce methane production in livestock, though these products have not been widely commercialized. Feeding one type of seaweed at 3% of the diet has resulted in up to 80% reduction in methane emissions from cattle. Fats and oils show the most potential for practical application to farming systems and have shown methane emission reductions of 15–20%.

There are two approved methodologies under the Emissions Reduction Fund (ERF) for using feed additives or supplements to reduce methane emissions and claim carbon credits.

  1. Reducing greenhouse gas emissions by feeding nitrates to beef cattle
  2. Reducing greenhouse gas emissions through feeding dietary additives to milking cows

Adding nitrates to the diet at a specified rate optimizes rumen fermentation, and changes the pathway of hydrogen to produce ammonia rather than methane. This can have the dual effect of reducing methane emissions while improving or maintaining animal performance. We recommend that producers seek specialist advice before using this option because overdosing can result in nitrate poisoning.

In the approved methodology for feeding nitrates to beef cattle, nitrate salt licks are substituted for animals previously fed urea, and are potentially applicable outside of feedlots.

The use of dietary additives is currently approved only for grazing milking cows, and includes the addition of eligible additives to increase fat content of the diet to reduce methane emissions.

Co-benefits to using feed additives

There are several benefits:

  • The reduced volume of methane formation may lead to better efficiency of feed utilization, given that methane emissions represent a gross energy loss from feed intake of about 10%.
  • Addition of fats and oils to the diet are a source of energy to the animal, as well as reducing methane.

Opportunities to use feed additives or supplements:

  • Reduction of methane emissions through feed additives, such as fats and oils, can reduce methane production by about 18% and offer energy and protein to the animal. For a 600 cow dairy herd (producing 100kg of methane per head per year) methane emissions could be reduced by 372 tons of carbon dioxide equivalent per year.
  • Reducing methane emissions is deemed ‘additional’ to normal management practices.

 Risks from using feed additives or supplements to reduce methane emissions

There are several risks:

  • The amount of additive ingested by livestock in paddock grazing systems is hard to regulate. Feed additives are more effective in feedlots and dairies.
  • Toxicity leading to ill health or death of livestock can result if nitrate supplements are introduced suddenly or ingestion is too high.
  • Long-term and consistent positive production responses to the addition of feed additives have not been found. These responses are essential for the commercial application of feed additives.
  • Fluctuations in carbon price may result in reduced or lost profit margins in a carbon farming project.

Source:

https://www.agric.wa.gov.au/climate-change/carbon-farming-reducing-methane-emissions-cattle-using-feed-additives

Carbon Farming (Part 02)2019-09-21T05:38:49-01:00

Carbon Farming (Part 01)

Carbon farming: reducing methane emissions from cattle using feed additives

Feed additives or supplements offer one approach to reduce methane emissions from ruminant livestock. Livestock produce significant amounts of methane as part of their normal digestive processes. Some feed additives can inhibit the microorganisms that produce methane in the rumen and subsequently reduce methane emissions.

Why we should reduce livestock emissions

In Australia, direct livestock emissions account for about 70% of greenhouse gas emissions by the agricultural sector and 11% of total national greenhouse gas emissions. This makes Australia’s livestock the third largest source of greenhouse gas emissions after the energy and transport sectors. Livestock are the dominant source of methane (CH4) and nitrous oxide (N2O), accounting for 56% and 73%, respectively, of Australia’s emissions.

How methane is produced by ruminants

Ruminant livestock – cattle, sheep, buffalo, goats, deer and camels – have a fore-stomach (or rumen) containing microbes called methanogens, which are capable of digesting coarse plant material and which produce methane as a by-product of digestion (enteric fermentation): this methane is released to the atmosphere by the animal belching.

The amount of methane emitted by livestock is primarily driven by the number of animals, the type of digestive system they have and the type and amount of feed consumed. Ruminants are the principal source of livestock methane emissions because they produce the most methane per unit of feed consumed.

Carbon Farming (Part 01)2019-09-21T05:38:49-01:00

Johne’s Disease Testing in Cattle

Consistent Johne’s Disease Testing Checks Beef, Dairy Disease Level

Regular diagnostic testing for Johne’s disease in beef and dairy herds is important because it keeps producers informed about the disease level in the herd, said Jennifer Street, Idaho State Animal Health Laboratory Principal Biologist.

“It’s very important that the producers in the beef and the dairy industry be regularly checking their herds for Johne’s disease,” said Street. “It is not uncommon for cattle to go asymptomatic in their herds. Therefore, they’re spreading the disease throughout their entire herd. If [producers] screen their animals on a regular basis, it’s all about catching the problem early, before needing to eradicate the problem once it has set it. At that point, it’s probably not good for that business owner’s livelihood – it just wipes out their herd.”

The Idaho State Animal Health Laboratory offers several different screening methods that test for Johne’s disease. Historically, they used culture which took weeks or months to get results. Now, they offer ELISA which checks to see if antibodies are present in the animal and when positive, it indicates the animal has been exposed to the disease agent at some point in time.

“More so now, we are actually using PCR, which is a DNA-based test to screen and, not only that, but to confirm if the animal does have Johne’s or not,” she said. “The Johne’s process for testing is so much quicker, and the sensitivity and the specificity for this new test is just amazing compared to the old methods.”

Because Johne’s disease is no longer regulated in Idaho, Street says they are seeing an increase in cases.

“Calves can be born with it, and they’ll be asymptomatic, so they may not show symptoms until they’re adults,” she said. “At that point, you probably have a problem, in which case it’s always best to check with either your local veterinarian or your state veterinarian and find a way to manage the herd and to test and screen for Johne’s.”

With PCR, the lab is able to “pool” samples, meaning they can take five fecal samples from a cow, and combine them into one test. Combining samples saves the producer money and if there is a positive result, the diagnostician can go back to the original samples and retest the samples individually to identify the positive animal or animals.

“The sensitivity of the test is very high, so we will pick it up if it’s there,” she said.

Source: http://www.thecattlesite.com/news/52673/consistent-johnes-disease-testing-checks-beef-dairy-disease-level/ 19 April 2018

Johne’s Disease Testing in Cattle2019-09-21T05:38:49-01:00

Dairy Calves – Optimist or Pessimist

Dairy Calves are Natural Optimists or Pessimists, Just Like Us

Some dairy calves are inherently optimistic or pessimistic, just as humans are, a new University of British Columbia study has found.

Recognizing these individual personality differences is important to ensure animals are treated well, says Professor Marina von Keyserlingk, who led the research team from UBC’s animal welfare program in the faculty of land and food systems.

“Sometimes we are tempted to see only the herd, even though this herd consists of different individuals who cope differently with stressful events,” said Professor von Keyserlingk. “It’s important to consider the individual’s perspective, because even if conditions are good, on average, some animals may still suffer.”

To gauge optimism and pessimism, the researchers set up an experiment involving 22 dairy calves. Before they started the experiment, they trained the calves to understand which of their choices would lead to a reward. In the training, each calf entered a small pen and found a wall with five holes arranged in a horizontal line, two-and-a-half feet apart. The hole at one end contained milk from a bottle, while the hole at the opposite end contained only an empty bottle and delivered a puff of air in calves’ faces. The calves learned quickly which side of the pen held the milk reward.

Once calves were trained, researchers presented bottles in one of the three intermediate holes, so that calves couldn’t be sure if they would be rewarded with milk. The researchers predicted that the most optimistic calves would approach the bottle even if it was positioned close to the location that earlier gave them an empty bottle and puff of air. In contrast, the most pessimistic calves would avoid approaching a bottle in the intermediate holes, even if it was close to the rewarded location. The calves varied in their responses, but individual calves remained consistent in their outlook and made similar choices three weeks apart. Researchers concluded that pessimism was a consistent individual trait, not just the result of temporary moods or emotions.

The study also assessed fearfulness through standard personality tests that monitor how calves react to unfamiliar situations, such as the presence of a stranger or a foreign object. Fearfulness and pessimism turned out to be closely related. “Calves that were more fearful were also more likely to view the glass as half empty,” said Professor von Keyserlingk. Research has shown that optimism and pessimism are also personality traits in humans, but little work has been done to investigate such personality differences in farm animals.

“The next step in our research will be to understand what type of rearing conditions helps ensure that an individual animal has a good life,” added Professor von Keyserlingk. “For example, more pessimistic calves may require different types of housing and management than we currently provide.”

Source: http://www.thecattlesite.com/articles/4366/dairy-calves-are-natural-optimists-or-pessimists-just-like-us/ February 2018

Dairy Calves – Optimist or Pessimist2019-09-21T05:38:50-01:00

How acetate stimulates milk fat synthesis in lactating dairy cows

Acetate Dose-Dependently Stimulates Milk Fat Synthesis in Lactating Dairy Cows

Background: Acetate is a short-chain fatty acid (FA) that is especially important for cows because it is the major substrate for de novo FA synthesis. However, the effect of its supply on mammary lipid synthesis is not clear.

Objective: The objective of this experiment was to determine the effect of increasing acetate supply on milk fat synthesis in lactating dairy cows.

Methods: Six multiparous lactating Holstein cows were randomly assigned to treatments in a replicated design to investigate the effect of acetate supply on milk fat synthesis. Treatments were 0 (control), 5, 10, and 15 mol/d continuously infused into the rumen for 4 d. Rumen short-chain FAs, plasma hormones and metabolites, milk fat concentration, and milk FA profile were analyzed on day 4 of each treatment. Polynomial contrasts were used to test the linear and quadratic effects of increasing the substrate supply.

Results: This substrate increased milk fat yield quadratically (P < 0.01) by 7%, 16%, and 14% and increased milk fat concentration linearly (P < 0.001) by 6%, 9%, and 11% for 5, 10, and 15 mol/d, respectively, comparing with the control treatment. Increased milk fat yield predominantly was due to a linear increase in 16-carbon FAs (P < 0.001) and a quadratic increase in de novo synthesized FAs (

Conclusions: Increasing acetate supply to lactating cows increases milk fat synthesis, suggesting that nutritional strategies that increase ruminal acetate absorption would be expected to increase milk fat by increasing de novo FA synthesis.

Source: Natalie L Urrutia Kevin J Harvatine ,The  Journal of Nutrition, Volume 147, Issue 5, 1 May 2017, Pages 763–769

How acetate stimulates milk fat synthesis in lactating dairy cows2019-09-21T05:38:50-01:00

Feeding Monensin for Dairy Heifers

Performance of dairy heifers fed high forage diets supplemented with Bambermycins, Lasalocid of Monensin

One hundred and twenty Holstein heifers weighing approximately 450 lb. at the beginning of the study were used to evaluate the impact of bambermycins (Gainpro®), monensin (Rumensin®), and lasalocid (Bovatec®) on performance when included in high forage diets fed ad libitum.

Heifers were housed in 24 pens (5 hf/pen) containing a super hutch. Pens were blocked (3 pens/block) from heaviest to lightest and randomly assigned within blocks to bambermycins, lasalocid, or monensin treatment. Bambermycins, lasalocid, and monensin were  mixed  with  fine  ground  corn  and  fed  as topdressing  to  deliver  20.25,  150, and 150 mg/hd daily, respectively. Diets were formulated (NRC 2001) to support body weight gains of less than 2 lb/hd daily using a mix of chopped alfalfa hay and corn silage (lighter weight heifers) or chopped alfalfa hay, chopped prairie hay, and corn silage (heavier weight heifers) supplemented with a mineral/vitamin premix. All heifers were fed a common total mixed ration, differing only in topdressing.

Diets were fed once daily for ad libitum intake. The study continued until the average body weight exceeded 800 lbs. (140 days on study) at which time they were inseminated and first service conception rate determined. Heifers fed monensin consumed less dry matter (DMI) (P <0.05) than those fed bambermycins and lasalocid during the periods d 29 to 56, 57 to 84, and 113 to 140 but DMI was similar across treatments during the 140- day study. No differences were observed for ADG over the 140-d study but heifers fed bambermycins and monensin tended (P =0.06) to gain faster during days 85 to 112 than heifers fed lasalocid.

Feed efficiency (gain/feed) varied, but heifers consuming diets containing bambermycins and monensin were more efficient (P<0.05) during days 85 to 112 and tended to be more efficient (P=0.051) during the 140- day study than heifers consuming lasalocid. Bodyweight, condition score, and hip height were similarly influenced by dietary treatments. First service conception rates were 60, 47 and 55% for heifers fed bambermycins, lasalocid, and monensin, respectively.

Source: Performance of dairy heifers fed high forage diets supplemented with Bambermycins, Lasalocid of Monensin, A. Hammond, J. E. Shirley, M. Scheffel, E. C. Titgemeyer, and J. S. Stevenson, Animal Sciences and industry, Kansas State University, https://www.asi.k-state.edu/research-and extension/dairy/nutrition.html

Feeding Monensin for Dairy Heifers2019-09-21T05:38:50-01:00