<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"><channel><title><![CDATA[Ruminant Pro - 'THE' site for livestock professionals]]></title><description><![CDATA[Articles]]></description><link>http://www.ruminantpro.com/ruminant-articles/</link><copyright><![CDATA[Copyright Ruminant Pro - 'THE' site for livestock professionals]]></copyright><generator>sNews CMS</generator><item><title><![CDATA[Forage utilization efficiency: an Australian perspective]]></title><description><![CDATA[  In recent times there has been a global shift back to pasture-based dairy farming led largely by the   “clean green”   push. Although philosophically this may be the correct move by the   dairy industry, care must be exercised that it is achieved in a   thoughtful, controlled way in order for the appropriate management to be   employed and sensible decisions made. The danger is in embracing   radical changes without thoughtful and balanced evaluation of the   potential consequences. Many times we see well-meaning farmers get into   trouble changing too quickly with too little homework.  
  The key to   profitability in pasture-based dairy farming is in understanding that   balanced rations are more difficult to achieve, and stockmanship reigns   as the most important skill. One needs to be very cow-focused to assess   the need for diet changes. Computers and consultants cannot substitute   for stockmanship. This paper will provide some basic concepts that need   to be considered if pasture-based dairy production is your quest.   
    
    
    
    THE MAJOR FACTORS AFFECTING MILK YIELD    
    
  Milk   production is the result of the coordination of many, many complex   metabolic and physiological events in the cow. Numerous factors affect   the efficiency with which the multitudes of cascades of biochemical   processes are carried out. Yet, only a handful of factors need be   attended with reasonable diligence by the farmer to allow all of the   necessary events to proceed successfully, such that good milk responses   are achieved in response to improved feeding levels.  
    
  For all   intents and purposes, there are only seven factors that require   significant management attention to maximise farm productivity. These   factors are presented in Figure 1. Of these seven management areas, only   cow condition and the four factors associated with the feed require   day-today attention. Unexpressed genetic potential lies latent in most   herds, and its improvement and the changing of calving patterns both   require strategic decision-making processes to be employed.   
    
    
       
    
    
      
    COW CONDITION: EVALUATING DIET BALANCE    
    
  If   one adheres to the 80/20 principle in farm management, body condition   management is the 20% which leads to 80% of the success on the animal   side. Cow condition is, in fact, the most important criterion for   assessing the success of dietary balance when used in conjunction with   milk production. It is also the key factor contributing to milk   components, health and fertility.Youmust become very astute at   monitoring and measuring, i.e., managing, body condition when most of   the diet is ‘unknown’.   
    
    
    
    FORAGE QUALITY AND PASTURE UTILIZATION    
    
  With   cow condition as a benchmark, this leaves the feed side, i.e., the   pasture (or any other forage for that matter) and supplements   (concentrate or roughage). It is the daily interaction of these that   primarily determines day-to-day milk yield and composition, body   condition, animal health and fertility. There is no difference between a   total mixed ration (TMR) and a pasture-based ration in this respect; it   is just a little more challenging to get it all right when basing the   diet on pasture. My own experience is that when the shift from TMR to   pasture is executed properly, yield and profitability can both be   preserved. Moreover, health and fertility will improve if we manage the   transition to pasture well.   
    
    
    
    FORAGE GROWING COSTS    
    
  As   an observer to Australian and New Zealand dairy industries, you could   be easily convinced that pasture is very cheap – so cheap that we waste   more than half of what we grow. Unfortunately this is not a rare   mindset. Australian and New Zealand farmers are still trying to survive   while working an out-dated paradigm – that pasture is cheap. Even now,   many advisers are still fertilising this perception.   
    
  A recent   conference paper (Tease, 1997) discussed several case studies in which   pasture costs were apparently consistently low, arguing that   supplementary feed costs were threatening our farmers’ prosperity. His   own data do not even support this conclusion (Figure 2). It is evident   from this figure that the cash outlay for home-grown feed is low, and   that purchased feed is of similar magnitude. Neither feed category   threatens farm prosperity. However, when analysing farm cash flows of   pasture-based dairy farm businesses, with an ounce of commonsense one   quickly realises that most farmexpenses relate, either directly or   indirectly, to the cost of growing pasture. I suspect the same is true   of other forage-based dairy farms, although it may be diluted a little   as farms move from home-grown forage to higher inclusions of   concentrates and purchased forage.  
    
  By including the labour,   overhead and depreciation costs, a very different picture of pasture   begins to emerge (Table 1). In the table we see that pasture is quite   expensive to grow. Also illustrated is the effect of increased pasture   yield on the unit cost of growth. Although it may cost more to increase   pasture dry matter yields, the higher yields produce significantly   cheaper feed.   
    
    
    
    PASTURE UTILIZATION EFFICIENCY: THE LARGEST IMPACT ON PROFITABILITY    
    
  It   is not enough simply to grow more pasture. Tonnes of pasture consumed   is the key to farm profitability. First we have to grow more pasture to   reduce the unit growing cost, and then we have to harvest the pasture   efficiently. To make total sense out of this picture, we need to provide   a series of examples. Table 2 expands on the previous table   illustrating the effects of land values and farming systems and the   effects of pasture utilisation on the true cost of pasture as a feed.   Once the real-cost adjustments are made and pasture utilisation is   considered, the homegrown feeds take on a new aura – they are not   automatically cheap feeds. Growing costs (in Table 2) range from 10-13.6   c/kg DM. However, it is not until you consider the utilised pasture dry   matter (UDM) costs that the real picture emerges. As you can see, every   effort must be made to maximise the yield (total tonnes) of harvested   pasture dry matter.   
    
    
        
      Figure 2.       Relationship between farm production level and feed cost.     
    
    
    
       
    
    
    
       
    
    
  Pasture   utilisation efficiency is the factor with greatest impact on farm   profitability. Figure 3 illustrates the relationship between gross   margin and pasture utilisation (UDM/ha). Clearly, as the UDM increases,   gross margin also increases. The poorer the pasture utilisation, the   more expensive the feed (Table 2). Once this is established, the   relationship betweenUDM and farm profitability becomes very strong as   can be seen from making these adjustments in the case study analysis   (Figure 4). Real pasture costs were in the order 14-28 cents/kg DM   ($140-280/t) which is precisely the same story illustrated in Table 2.   Without focus and an understanding of the real costs of pasture   production, it would be easy to romance the pasture-based farming system   with disastrous consequences.   
    
    
       
      
      Figure 3.       Relationship between pasture dry matter utilised and gross margin.     
    
    
    
    MAXIMISING PASTURE USE EFFICIENCY  
      
  Only two aspects of pasture management require discussion:  
  
    1. Increasing the harvest efficiency of pasture currently grown.  
  2. Improving pasture yields.  
  
  Management priorities must, very definitely, be in this order since   there are few farms on which grazing is the dominant means of harvest   where utilisation of pasture is optimal. Improving pasture yield is   outside the scope of this presentation. Suffice to say that species   selection, grazing, fertiliser and irrigation management are all vital   components.  
      
      
      
    INCREASING PASTURE UTILISATION EFFICIENCY: FORAGE QUALITY IS THE KEY  
      
  Numerous   management factors influence the efficiency with which pasture is   harvested. The most obvious are presented in Figure 5 and three of these   are closely related: grazing management, pasture species and fertiliser   management. Each of these has a tremendous impact on forage quality.   
    
  The   quickest and most significant means of increasing pasture use   efficiency is to optimise rotation length (i.e., the period fromone   grazing to the next).   
    
    
      
    
      Figure 4.       Relationship between farm production level and component cost of production (with revised home-grown feed costs).    
    
    
    
      
    
      Figure 5.       Major factors affecting pasture utilisation efficiency.    
    
    
    
  Rotations   that are too short reduce dry matter yields, while rotations that are   too long limit pasture consumption by the cow as forage quality   declines.   
    
  Owing to the relationship between neutral detergent   fibre (NDF) and intake, no amount of concentrates can compensate for a   poor quality forage base (Van Soest, 1994; Mertens, 1983). In Figure 6,   this is illustrated on three basal rations containing either A) good   quality (lucerne), B) fair quality (corn silage), and S) poor quality   (bermuda grass) forages, all optimised for fibre.Without going into   mathematical detail, the relationship described below in Equation 1 can   be used to describe the limitations to intake, and thus production level   (Mertens, 1983):  
    
    
      
    
    
  The   underlying mechanism for the relationship between intake and NDF in   Equation 1 is obvious. As fibre quality improves, intake, digestibility   and passage rate all increase. The line in Figure 6 is there as a   reminder that as milk yield improves, the percentage of NDF in the   ration can be reduced since the maintenance of the rumen mat requires   kilograms of NDF, not percentages.  
    
  An understanding of the   physical role of NDF leads us to the limitations of our pasture-based   management system. Figure 7 clearly illustrates the intake boundaries   for our pasture (or forage)–based dairy rations. Once we accept that   intake is primarily determined by dietary NDF, we quickly recognise that   there is a limited number of feasible ration solutions for cows at   different production levels. More importantly, the number of feasible   rations diminishes as production expectations rise and/or forage quality   declines. It is rather simplistic, but it serves as a guideline to get   diet components in the right ballpark and is an incredibly good tool   when educating farmers on the importance of fibre quality. Simply put,   as NDF increases, dry matter intake decreases.  
    
  Typically our   pasture NDF values increase quickly after optimum grazing height   (maturity).A rotation only seven days too long may result in a 7-10%   unit increase in pasture NDF and cause intakes to fall by up to 0.7% of   liveweight (Table 3) or 2 kg DM/day. Not only will dry matter intake   decrease, but energy density of the pasture also falls (by ~1MJME/kg   DM), ultimately sacrificing 7-8 liters of milk/day. Table 3 clarifies   this point, and the important role concentrates play in increasing total   dry matter intake.  
    
    
      
    
    
    
  From the perspective of Figure 7, we can assemble a second equation:  
    
    
      
    
    
  Thus,   the limit to feasible intakes is determined with liveweight as the   controller, and NDF as the key variable to be managed. In practical   terms this means:  
    
    
    A 500 kg cow will have an intake limitation of approximately 6.0 kg NDF.  
      
    
      
      
      Figure 6.       The relationship between milk yield and NDF.    
    
    
    
      
    
      Figure   7.       Using the NDF-energy intake system to identify the range of feasible   rations for cows of different production levels (Mertens, 1992).    
    
    
    
      A 600 kg cow will have an intake limitation of approximately 7.2 kg NDF.    
      
  This   is incredibly important to understand when managing a pasturebased   dairy ration. A cow can only fit somuch in! Pasture quality management   is the most challenging aspect of low-cost dairying systems. Even   relatively small changes in pasture quality have an enormous impact on   dry matter intake as noted in Table 3. The other challenges such as   dealing with differences in genetic potential, nutrient balance, etc.,   pale by comparison.  
    
    
    
    USING SUPPLEMENTS TO MAXIMISE PROFITS FROM PASTURE    
    
  It   is the number of tonnes of pasture dry matter harvested that primarily   determines whether profits are made or lost. The most profitable means   of achieving high levels of pasture utilisation is to take advantage of   the complementary properties concentrates offer.  
    
    
    
    THE ROLE OF SUPPLEMENTS IN THE PASTURE-BASED FARMING SYSTEM    
    
  Supplements   provide the vital links between pasture management and animal   management. More aggressive grazing reduces the pasture allocation per   cow, often reducing the consumption of pasture per cow. This in turn   compromises the efficiency of feed conversion. More importantly, the   risk of running out of feed increases as grazing management is   intensified through higher stocking rates, restricted use of fibrous   supplements and improved genetic potential of the herd. Supplements,   therefore, play the critical role of insurance against running out of   feed, and help maintain high feed conversion efficiencies. If used as an   integral part of themanagement system, supplements result in   significant profits. However, this is rarely seen in practice.  
    
    
    
    ECONOMICS OF CONCENTRATES IN PASTURE-BASED DAIRY RATIONS    
    
  Dairy   farmers in southeastern Australia and New Zealand rely heavily on   pastures to provide the nutrients required for milk production.   Typically, lactating dairy cows receive rations similar to those   presented in Table 4. The most common ‘reason’ for concentrates to be   used on farm is the recognition that they contain the potential to   realise high production levels per cow and simultaneously per hectare by   intensifying grazing management. In practice, this rarely happens   without external guidance due to a fall in pasture utilisation when   supplements are fed. The net result is usually a marginal cost/benefit   scenario from supplement use (Table 5). Even if production per cow and   per hectare are improved, responses such as this fail to capture our   audience, but rather leave them a little frustrated.  
    
    
    
    SUBSTITUTION    
    
  In   understanding Equation 2, it becomes obvious that as NDF intake   approaches maximum, the use of supplements will force some forage out of   the diet. The frustration of substitution is that the theoretical   responses to supplements are rarely met.  
    
  The energy in cereal   grain (12.2-12.7 MJ ME/kg DM) is sufficient for about 2.3 litres of   milk. At 23.1 cents/kg for concentrate and 25 cents/liter for milk, this   represents an enormous opportunity for profit. Even if you only get   half of this, it still represents pretty good value for money! Yet   typical responses to concentrate supplements are sufficiently poor that   their value is still subject to a good deal of debate.  
    
    
      
    
    
      
    
    
  Cereal   grain, specifically wheat with an energy density of 12.7 MJ/kg DM,   contains sufficient energy for about 2.6 liters of milk, yet such   responses are never recorded. The extent to which the response falls   short of the 2.6 liters/kg DM wheat is the extent to which one or other   of the following have occurred:  
  
    substitution   
    the imbalance of nutrients in the rumen, or   
    the partitioning of nutrients between milk production and body tissue   
  
  Since substitution refers to the drop in pasture intake caused by the   intake of supplements, the production response is usually less than the   potential intake. In turn, the marginal rate of response often becomes   just that – marginal.  
    
    
    
    MANAGING SUBSTITUTION    
    
  Management   of fibre quality alone is insufficient to extract the best from   pasture-based dairy systems. The seeking of feasible dietary solutions   also entails a quest for matching supplements to pasture (forage) to   ensure maximum use and control of quality pasture.  
    
  Substitution   will be minimised by dietary balance, body condition management and   grazing management; however, an element will remain.  
    
  This can be   eliminated by additional cows to maintain or increase the effective   grazing pressure. When the system is managed well the profitability   cannot be disputed. Table 6 shows the progress made by BESTfed Nutrition   clients as our working relationship develops.  
    
    
      
    
    
    
  Unless   moderate increases in stocking rate occur in conjunction with   significant increases in milk yield, supplements will provide little   economic benefit to the farm business.When used as an integral part of   the management of the dairy feedbase, supplements have a large positive   cost/benefit ratio (Table 6). It is also evident that as production per   cow rises, margin over feed cost also rises. When the effects of   increased concentrate use combine with increased stocking rates and   higher production per cow, the effects on margin over feed costs per   hectare are huge.    &nbsp;      
by Les Sandles - Best-fed Nutrition  
]]></description><pubDate>Sat, 31 Jul 2010 23:39:00 +0000</pubDate><link>http://www.ruminantpro.com/ruminant-articles/range-pasture-grazing/forage-utilization-efficiency-an-australian-perspective/</link><guid>http://www.ruminantpro.com/ruminant-articles/range-pasture-grazing/forage-utilization-efficiency-an-australian-perspective/</guid><author>Sat, 31 Jul 2010 23:39:00 +0000</author><comment></comment></item><item><title><![CDATA[Boosting births: Keeping mastitis out of your herd may improve reproductive success]]></title><description><![CDATA[   Mastitis in your herd may be costing you more money than you think,   suggests a study linking mastitis and poor reproductive performance in   dairy cows.  
  The average clinical mastitis case costs you, the producer, an   estimated $150. This figure accounts for economic losses from discarded   milk, antibiotic treatment, decreased lactation production and your time   managing the treated animal. However, mastitis costs may go deeper than   these obvious losses. Udder infections may be hampering your herd's   reproductive success.  
  University of Tennessee researchers have   investigated how clinical and subclinical mastitis affect reproduction   measures. They analysed data gathered over a 10-year period from 758   Jersey cows in their research herd. The microbiological data was from   quarter milk samples collected from lactating cows every four to eight   weeks. Researchers defined subclinical mastitis as a cow with two   consecutive milk cultures containing the same organism. Milking   personnel identified clinical cases. Milkers practised teat dipping and   used antibiotic therapy at dryoff and to treat clinical cases. Personnel   measured reproductive performance by days to first service, days open   and services per conception.  
  Researchers divided data into   groups. The cows with mastitis before first service (374) showed a   significant increase in days to first service, days open and services   per conception compared with cows with no mastitis or a case developing   after pregnancy (326). The result was the same for clinical and   subclinical mastitis.  
  The 35 cows with clinical mastitis between   first service and confirmation of pregnancy had a significant increase   in days open and services per conception compared with cows with   subclinical cases or no mastitis (see Table 1). Cows with prolonged   udder infections (subclinical infections that eventually became clinical   cases during the breeding period) were most severely affected for the   three reproduction parameters. The reliability of the results may be   questionable because this group had only six cows. Nonetheless, the   impact on reproduction was large and deserves attention.   
  &nbsp;  
      Table 1.       Effect of mastitis in cows between first service and confirmed pregnancy on reproductive parameters.      
    
      
  &nbsp;  
  Research   often provides answers while leading to more questions. Scientists   don't fully understand the link between mastitis and reproductive   performance. Some work has shown a cow's response to mastitis caused by   gram-negative pathogens (like E. coli and Klebsiella) has a negative   effect on its hormonal profile and follicular development. Other studies   suggest that prostaglandins are released in the inflammatory response   to gram-negative infections. This prostaglandin increase acts similar to   a prostaglandin injection, which can change the length of a cow's heat   cycle and may cause the loss of a developing embryo in a bred cow. In   the Tennessee study, gram negative and gram positive bacteria caused   clinical mastitis equally-here, the type of bacteria had no bearing on   results.  
    
  These suggested mechanisms of mastitis affecting   reproduction seem plausible for cows contracting an udder infection   during the breeding period. However, researchers are more skeptical   about mastitis' negative effects on reproductive performance for the   cows that develop mastitis early in lactation. More research is needed   to understand this relationship.  
    
  Some aspects of the Tennessee   study may affect its relevance for Ontario producers. Ontario's dairy   population is over 90 per cent Holstein, so a Jersey herd study's   relevance may be questioned. Nevertheless, a study conducted on the   University of Florida Holstein herd to evaluate clinical mastitis and   reproduction reported similar results. However, the warmer climate and   different feeding programs used in the southern U.S. may decrease the   relevance of this study to Ontario dairy herds.  
    
  Nonetheless,   study results stress the importance of striving to control udder   infections in your herd. There are the obvious direct costs of clinical   or subclinical mastitis, but there's growing evidence of the indirect   cost of reproductive inefficiency. Three U.S. research studies have   reported that the estimated cost of each day open after 90 days ranged   between 50 cents and $4.00 US. The importance of managing your herd to   prevent mastitis in the first 60 days of lactation is obvious, but   mastitis control needs to remain a top priority right through a cow's   breeding period and beyond.   
    
Given the potential economic   importance of these research findings, following a mastitis control   program would benefit your bottom line. One program, recommended by the   National Mastitis Council (NMC), includes 10 steps that involve all   areas that may affect mastitis in your herd. (see Table 2 below).  
  
      Table 2.   NMC recommended 10-step mastitis control program    
  
       1.   Establish udder health goals for your herd   
      2.   Maintain a clean, comfortable environment   
      3.   Use proper milking procedures   
      4.   Properly use and maintain your milking equipment   
      5.   Keep good records   
      6.   Manage clinical mastitis appropriately during lactation   
      7.   Use effective dry cow management   
      8.   Use biosecurity protocols to prevent the spread of contagious pathogens and when marketing chronically infected cows   
      9.   Monitor your herd's udder health status regularly   
      10.   Periodically review your mastitis control program   
  
    
    
  Setting   udder health goals and monitoring them regularly basis is an important   first step. Proper stall maintenance and adequate bedding will keep   teats clean and dry in between milkings. Keeping the maternity area   clean and well bedded will protect fresh cows from udder infection   during their most vulnerable period. Good udder preparation practices   prior to milker attachment are important. Applying the milker to clean   and dry teats is a must.   
  Record keeping is extremely important   for monitoring clinical mastitis trends in your herd. Prior to treating a   clinical mastitis case, collect a milk sample of the infected quarter   and submit it for bacteria identification. This information can be used   to determine a bacteria profile for your herd, which can help identify   management practices that may need attention. With the help of your   veterinarian develop treatment strategies that are appropriate for the   mastitis cases in your herd.   
  Using dry cow antibiotic therapy   after the last milking is important to help cure existing udder   infections and prevent new infections in the early dry period. Using   alcohol swabs to prepare teats prior to dry cow treatment is important   to avoid contaminating the udder with bacteria from the outside of the   teat. Enrolling in an individual cow somatic cell count program can help   detect subclinical mastitis before it becomes a clinical mastitis   problem.   
  Your veterinarian and DFO's udder health specialists   are excellent resources who can advise you on developing and   implementing a mastitis control program for your farm. The benefits of   implementing sound practices to control mastitis go further than a   decreased incidence of the disease. Increased reproductive performance   in your herd is another benefit that is becoming more evident.  
  &nbsp;  
    
  by Jeromy Ten Hag - Milk Quality Assurance Program Lead / OMAFRA
  
]]></description><pubDate>Sat, 31 Jul 2010 23:37:00 +0000</pubDate><link>http://www.ruminantpro.com/ruminant-articles/breeding-and-genetics/boosting-births-keeping-mastitis-out-of-your-herd-may-improve-reproductive-success/</link><guid>http://www.ruminantpro.com/ruminant-articles/breeding-and-genetics/boosting-births-keeping-mastitis-out-of-your-herd-may-improve-reproductive-success/</guid><author>Sat, 31 Jul 2010 23:37:00 +0000</author><comment></comment></item><item><title><![CDATA[Direct Connection Environmental Mastitis and Reproductive Performance]]></title><description><![CDATA[  Keeping environmental mastitis in check during summer and fall can boost your herd's reproductive performance.  
  The   predictable pattern of increased environmental mastitis during late   summer and fall could be taking a near-invisible toll on your bottom   line. You can plainly see direct costs of clinical mastitis in   early-lactation cows: discarded milk, costly treatment and, frequently,   reduced milk production for the rest of their lactations. What you may   not see is the indirect cost stemming from reduced reproductive   performance.  
  Mastitis has long been suspected of adversely   affecting reproduction. Past research has shown that cows with clinical   mastitis caused by E. coli don't have normal reproductive cycles. One   study suggested the immune response triggered by an E. coli infection   could alter hormone and ovary functions. Other work has shown that any   clinical mastitis, not just cases due to E. coli, will cause cows to   take longer to conceive. Researchers still need to determine how and why   this occurs.  
  While studies done under experimental conditions   have convincingly shown that mastitis hurts reproduction, little field   work has been done on how clinical mastitis impacts reproduction in   working dairy herds. However, a short report in a recent issue of   Veterinary Record does shed light on this subject. The report describes a   study done by practising British veterinarians who looked at how   mastitis was affecting reproduction in some of their clients' herds.   
  The   vets collected information from detailed records of seven dairy herds   in their practice. The producers had been tracking clinical mastitis   cases as well as routine reproductive information such as calvings,   heats and breedings. They routinely recorded cow identities, lactation   numbers, dates of mastitis cases and any treatments given.  
    
  For   the study, the vets matched a clinically infected cow with an unaffected   herdmate having the same lactation number and similar calving date.   They compared the reproductive performance of these pairs-a commonly   used, powerful study technique.  
    
  The vets then put pairs of cows   into four groups according to when the mastitis case had occurred   relative to artificial insemination (AI):  
    
  - up to three weeks before breeding;   
  - three to six weeks before breeding;   
  - up to three weeks after breeding;   
  - six weeks after breeding.  
    
  Cows   contracting mastitis within the three-week period before insemination   were only half as likely to conceive compared with the uninfected cows   they were paired with. Reproductive performance was the same for cows   with and without mastitis in the other three groups.   
    
  Both sets   of cows-with and without mastitis-were bred about the same time after   calving, 81 and 83 days for infected and non-infected cows respectively.   This suggests both groups of cows were fertile and likely had the same   opportunity to become pregnant had mastitis not occurred.  
    
  How   mastitis caused this effect is unknown, but this research suggests the   negative effect was likely exerted some time during the 21-day breeding   cycle just prior to AI. The mastitis case may have reduced conception by   affecting the developing oocyte (egg), follicular growth or   ovulation-inducing hormones. The British vets described this specific   effect of mastitis as "the window of opportunity" to interrupt   reproduction.  
    
  As environmental mastitis becomes more prevalent in   a herd, the probability increases that more early-lactation cases will   occur. Herds in Ontario's Sentinel project a few years ago recorded the   greatest number of cases in the first 21 days after calving, before   breeding starts. However, a significant number of cases were recorded   until 70 days after calving. Then, as lactation progressed, the numbers   became much more sporadic. With increased environmental mastitis in the   summer, the occurrence of such cases in some cows close to breeding is   likely.  
    
  Most mastitis cases in the British study were treated.   That may have reduced the duration of cases and damage to the cows'   udders, but treatments close to breedings did not prevent the adverse   impact of mastitis on conception. Mastitis prevention would be the only   way to improve reproductive performance.  
    
  Ontario herds commonly   complain about poor reproductive performance, particularly in summer.   Many herds frequently adopt solutions such as intensive timed breeding   programs without ever identifying the underlying problem and resolving   it. For some, perhaps, solving a mastitis problem should come first.  
    
  If   you have good records of breedings and mastitis cases, you can find out   whether mastitis is hurting your herd's reproductive performance. Your   vet or dairy herd improvement representative can help you set up a   standard system for recording mastitis cases and treatments. Then you   can consult your vet to analyse the relationship between mastitis-and   other metabolic conditions-and reproductive performance.  
    
  Once you   understand underlying conditions that cause poor reproductive   performance, you can take the specific steps to correct them. On some   farms, preventing mastitis during the breeding period may be the best   way to improve conception.  
    
    
    Early-lactation cows more prone to udder infections    
    
  Ontario's   average bulk milk somatic cell count (SCC) now hovers around 250,000   cells per millilitre annually. Each year it ranges from monthly lows of   200,000 in winter to highs around 300,000 in late summer and fall   months. Over the last 10 years, this pattern has become quite   predictable.  
    
  Every summer and fall, many Ontario herds experience   months with more mastitis cases and high SCCs. Bacteria that thrive in   the cow's environment-Strep uberis, Strep dysgalactiae, E. coli and   Klebsiella-cause many of these seasonal problems.  
    
  The timing   often coincides with hot, humid weather that favours multiplication and   survival of these bacteria in the cow's environment. When environmental   bacteria numbers are high, there is a far greater chance they will enter   a teat end from manure in bedding or alleys and infect a quarter. An   udder infected with environmental bacteria is more likely to progress   into a clinical mastitis case with visibly abnormal milk and even a sick   cow.  
    
  Typically, environmental mastitis outbreaks cause clinical   mastitis in early-lactation cows. These animals have a reduced ability   to fight off new udder infections. This suggests the cows' resistance   must be low and bacterial numbers must be high to cause a seasonal   problem.   
  &nbsp;  
    
  by Ann Godkin - OMAFRA
  
]]></description><pubDate>Sat, 31 Jul 2010 23:36:00 +0000</pubDate><link>http://www.ruminantpro.com/ruminant-articles/breeding-and-genetics/direct-connection-environmental-mastitis-and-reproductive-performance/</link><guid>http://www.ruminantpro.com/ruminant-articles/breeding-and-genetics/direct-connection-environmental-mastitis-and-reproductive-performance/</guid><author>Sat, 31 Jul 2010 23:36:00 +0000</author><comment></comment></item><item><title><![CDATA[Stillbirths and Calf Survival]]></title><description><![CDATA[  The percentage of stillbirths has been steadily increasing but you can take steps to improve that rate on your farm.  
  You'll   soon be able to improve the chances of having a live calf on the   ground-especially from a first-calf heifer-by looking closely at bull   proofs for calf survival rates due to be published in early 2008. Recent   numbers suggest that stillbirths have been rising for Canadian   Holsteins, although the reasons still aren't clear.  
  Canadian   Dairy Network statistics released last year show that Holstein   stillbirth incidence with first calvings has risen to 12 per cent from   10 per cent over the past five years. The stillbirth rate for cows   having their second or later calvings is lower at six per cent, but   still up slightly from the previous five per cent.  
  These numbers   mean that nearly eight per cent of all calves are born dead or don't   survive past 24 hours. However, the statistics don't distinguish whether   the reason is due to genetics, farm management or other factors that   might indicate why rates have gone up.  
  Stillbirth data from other   parts of the world are similar to Canadian statistics. Earlier U.S.   research found that stillbirth incidence increased to 13.2 per cent in   1996 from 9.5 per cent in 1985. Swedish research indicates a stillbirth   rate of about 10 per cent in Swedish Holsteins at first calving.  
  In   contrast to these results, a recent Norwegian study of calving   difficulties and stillbirths in Norwegian Red cattle found that the   frequency of stillbirths was three per cent at first calving and 1.5 per   cent for second and later calvings. The rate was unchanged between 1978   and 2004.  
  In the Swedish study, where Swedish Holsteins had a 10   per cent stillbirth rate, the Swedish Red and White herds reported   about half that rate. The Scandinavian red breeds seem to have low   stillbirth or good calf survival in common.   
  Canada, Norway and   Sweden define a stillbirth as a calf carried to term, or at least longer   than 260 days, and born dead or dying within 24 hours of birth. The   U.S. and some other countries consider a stillbirth has occurred within   48 hours of calving. It can be expected that U.S. averages are slightly   higher than numbers reported in Canada, Norway and Sweden.  
    
  Stillbirth,   like calving difficulty, is a much larger problem in first-lactation   calving than in later calvings. Incidence in second and later lactations   drops to half or less than the rate for first lactations.  
    
  The   cost to the industry of this many dead calves is quite substantial. In   Ontario, with a population of 340,000 dairy cows, about 300,000 calves   are born every year. If 30 per cent of the cows are in first lactation,   then 90,000 calves are born to them. Reducing the current stillbirth   rate of 12 per cent to the Norwegian Red rate of three per cent would   produce 8,100 more live calves per year from first calvings. Decreasing   stillbirths for second and later calvings to 1.5 per cent from six per   cent on 210,000 calvings would result in an additional 9,450 live   calves.  
    
  That's a total of 17,550 more live calves. If we value a   bull calf at $150 and a heifer calf at $400, the total loss or missed   potential compared to the Norwegian rate is $4.8 million per year in   Ontario.   
    
  A Cornell University study published this year paints   an even more serious picture. In a study of seven large dairy farms,   researchers found that cows having stillbirths had significantly   increased risk of culling or death throughout the subsequent lactation.   Median days open increased by 88 days compared to cows that had live   calves. They concluded that stillbirth losses are far greater than just   the value of the calves.  
    
  Stillbirth is influenced partly by the   calf [direct] and partly by the mother that is giving birth [maternal].   Research has shown there is little or no relationship between maternal   and direct genetics for stillbirth, and some studies show a negative   relationship. To make any selection progress, we need to look at both   traits.  
    
  Stillbirth heritability is considered low. The Norwegians   found heritabilities of .07 to .08, similar to but slightly less than   heritabilities for calving ease. Norwegian and Canadian research found   lots of genetic variation, so sire selection to improve calf survival   and reduce stillbirths is possible over time.  
    
  Norway places only   one per cent emphasis on stillbirths in its national selection index.   With such a low incidence rate, there would be little value in putting   emphasis on improving stillbirth rate. In countries with higher levels,   however, calf survival traits should get more emphasis.  
  Stillbirth   incidence is highly related to calving difficulty. According to the   Norwegian study, maternal calving difficulty is correlated with maternal   stillbirth and direct calving ease with direct stillbirth. Calving   difficulty increases the probability of stillbirth, due mainly to trauma   and anoxia, a lack of oxygen.  
  However, research performing   post-mortems on stillborn calves has found that half the deaths were not   related to calving difficulty. As well, no cause of death could be   determined on a third of the calves, which should warrant further   research to find a cause or causes.  
  A large crossbreeding trial   is being conducted in Canada using Norwegian Red sires on Canadian   Holsteins, but it's too early to draw conclusions about calving ease or   stillbirth incidence. Crossbreeding trials in California showed   crossbred calves sired by Scandinavian Red sires from Holstein   first-calving heifers had lower calving difficulties and a lower   incidence of stillbirths. The crossbred heifers also had a lower   incidence of calving difficulty at three per cent and stillbirths at 5.1   per cent than their Holstein counterparts with rates of 17.7 per cent   for difficult calving and 14 per cent for stillbirths.  
  Canadian   breeders will soon have proofs published for calf survival traits:   Direct Calf Survival, a measure of the survival rate of a bull's   offspring, male or female; and Maternal Calf Survival, a measure of the   ability of a bull's daughters to have a live calf. Both maternal and   direct traits contribute to whether you get a live calf on the ground,   so pay attention to both. In the future, calf survival traits will also   be included in some form in the Lifetime Profit Index to provide some   overall selection to improve calf survival in Canada.  
  You may   want to emphasize calving ease and calf survival information in sire   selection for your first-calf heifers. You should also regularly report   all stillbirths, whether male or female, to make Canadian genetic   information as accurate as possible.  
  The knowledge gained from   these studies, especially with first-calf heifers, can help you manage   them at calving time to improve the chances of having a live calf.   Discuss with your veterinarian the best strategy to minimize calving   problems and calf losses, and maximize calf survival.   
  &nbsp;  
    
  by Blair Murray - OMAFRA
  
]]></description><pubDate>Sat, 31 Jul 2010 23:34:00 +0000</pubDate><link>http://www.ruminantpro.com/ruminant-articles/calf-management/stillbirths-and-calf-survival/</link><guid>http://www.ruminantpro.com/ruminant-articles/calf-management/stillbirths-and-calf-survival/</guid><author>Sat, 31 Jul 2010 23:34:00 +0000</author><comment></comment></item><item><title><![CDATA[General Guidelines for Managing Pastures for Dairy Cows]]></title><description><![CDATA[  The decision to use pasture as a major source of nutrients for milking   cows must be accompanied by a strong commitment to properly manage the   pasture. Determining soil fertility status, choosing a fertilization   program, selecting appropriate forage species, and controlling grazing   are important elements of a pasture management program.  
  &nbsp;  
    Soil Testing and Pasture Fertilization    
  Soil nutrient status varies widely from field to field on many conventional dairy farms. Soils in   "herd pastures"      that serve as lounging areas for cattle, often are very high in   phosphorus and potassium, but soils from an adjacent field where   harvested forage is grown may be low in these nutrients. Soil testing   allows identification of soils that are high in nutrients, where only   nitrogen fertilizer is needed to grow grass, and those that are low in   nutrients, where phosphorus, potassium, and perhaps other nutrients will   be needed in addition to nitrogen.  
  How often should grazed   pastures be fertilized? A good starting point is to think about what   fertilization does for the pasture. Generally, we fertilize to increase   the yield and/or nutrient density of the forage. In Florida soils, a   shortage of nitrogen almost always limits grass yield, so nitrogen is   the most-needed fertilizer nutrient in many cases. Nitrogen is easily   leached from sandy soils by heavy rains, so fertilizer applications may   need to be fairly frequent and at rates of 40 to 60 lb/acre per   application. When temperature and rainfall are high in summer, monthly   applications of nitrogen may be needed to keep the grass growing well   and maintain a relatively high crude protein. During other times of the   year, fertilization can be less frequent. If there are a relatively   large number of cows per acre (high stocking rate) on the pastures,   correspondingly high rates of nitrogen fertilizer will be needed to   provide enough grass. Lowering stocking rate will allow for a lower rate   of nitrogen. It is important to keep in mind that grazed pastures will   require less fertilizer than hay fields because a high proportion of the   nutrients consumed by grazing livestock are returned to the pasture in   their feces and urine instead of being harvested and moved off the field   as in a hay operation.  
  What about phosphorus and potassium?   Because phosphorus and potassium generally are less likely to be leached   out of the soil than nitrogen, they can be applied less often. One to   two applications per year according to soil test should be adequate. If   the soil test report does not recommend these nutrients,     do not add them    . Using unneeded fertilizer wastes a limited natural resource, costs money, and may hurt the environment.   
    
  Soil   pH can affect growth of forages, and lime is applied to raise the pH   when soils are too acidic. What pH is too acidic for grasses? If soil pH   is lower than 5.0, liming of bahiagrass pastures is recommended. For   other perennial grasses, like bermudagrass, stargrass, limpograss, and   rhodesgrass, liming is recommended when the pH is lower than 5.5. For   economic reasons, apply at least one ton per acre whenever lime is   applied. The ammonia forms of nitrogen fertilizer acidify the soil, so   the higher the ammonium nitrogen rate the more often lime will be   needed. A general rule for heavily fertilized pastures is that liming   will be needed every three to five years. Always soil test before   deciding to lime, however. Don't overlime because high soil pH (more   alkaline) leads to plant deficiencies of micronutrients (manganese,   zinc, iron, and copper).  
    
    
    Choice of Forage Species    
    
  In   addition to fertilizer management, choice of forage species is   important. The species chosen depends upon many things. Two of the most   important are location in the state and soil type. North of Orlando,   most producers choose bermudagrass, pearl millet, or sorghum-sudangrass   hybrids for summer grazing and rye or ryegrass in winter. In south   Florida, most producers are using either stargrass (sometimes called   Giant Callie Bermudagrass) or bermudagrass in summer and ryegrass in   winter. The hybrid bermudagrasses like Coastal, Callie, and Tifton 85 do   not grow well on wet sites, but common bermudagrass tolerates wet soils   well. The hybrid bermudagrasses outyield common bermudagrass and are   more nutritious. Stargrass is not cold tolerant enough for north   Florida. In south Florida, stargrass is better adapted to wetter soils   than hybrid bermudas. Pearl millet is an annual and best grown on   moderately well to well-drained soils while the sorghum-sudangrass   hybrids, also annuals, can tolerate wet soils better. Young growth of   sorghum-sudangrass hybrids after drought or cold can contain prussic   acid, a very potent toxin, so care is required if this forage is used.   Rhizoma peanut is a high quality legume for dryer sites. It does not   yield as much as the grasses, but doesn't require nitrogen fertilizer,   and stands last for many years. Annual ryegrass and clovers (red, white,   or crimson) are good choices in north Florida for cool-season grazing   on moist soils or when irrigation is available to get them established.   Rye is adapted to dryer north Florida sites, but grows well in a mixture   with ryegrass on moderately wet sites. In south Florida, the growing   season for cool-season annuals is quite short and as a result they may   not be an economical alternative for some producers. Those who use   cool-season forages generally have greatest success with annual   ryegrass. Establishment of the annuals (pearl millet,   sorghum-sudangrass, and all of the cool-season forages) is risky without   irrigation. During some years, timely rains will ensure good stands,   but in other years rain will not come and stand failures will occur.   Having access to irrigation reduces risks associated with grazing   dairies.  
    
    
    Grazing Strategies    
  Once   we have these forages, how do we graze them? For most dairy situations   the choice of rotational stocking (also called rotational grazing) is a   good one. Cows are moved every 12 to 24 hours to a new pasture and the   pasture where grazing just ended is given time to rest and regrow before   it is grazed again. The advantages of this practice over continuous   stocking include better distribution of manure, more consistent diet for   the cows, and higher yields and increased longevity of the pasture.   
  How   close should the pasture be grazed? This depends on the forage being   used, on production goals for the herd, and on how quickly the pasture   will be grazed again. Taller growing grasses like hybrid bermudagrass,   stargrass, and pearl millet generally should be grazed no lower than a   stubble of 6-10 inches, while shorter grasses like bahiagrass and common   bermudagrass can be grazed to 2-4 inches. Grazing close puts more   stress on the pasture because it removes most of the leaves that the   plant uses to produce its food. Short rest periods following close   grazings don't allow plants time to restore their leaf area, and when   grazed again these plants are forced to use energy reserves to regrow.   As the plants reserves are depleted, growth rates will slow and   eventually plants will die. Close grazing also forces the cows to graze   more stem, which reduces digestibility and intake and results in lower   milk production.  
  Stocking rate determines how close the pasture   is grazed and it is one of the most important decisions that a pasture   manager makes. The ideal stocking rate in a given situation is affected   by the forage, weather conditions, fertilization, amount of concentrate   being fed, and production goals. We have found some ballpark numbers   that can serve as a starting point. Well-fertilized bermudagrass,   stargrass, and pearl millet have carried from three to four milk cows   per acre during June through September when those cows were receiving   approximately 20-25 lb of concentrate per head per day. Rhizoma peanut   has carried from two to three cows per acre during the same period when   cows were receiving the same amount of concentrate. Spring and fall   stocking rates are less for all of these forages. When drought   conditions hit, stocking rates are much less. Winter pastures carry   fewer animals, between one and two animals per acre in many cases.   Winter stocking rate may be greater than this if irrigation is available   for drought periods and relatively high rates of nitrogen fertilizer   are used.   
  Someone thinking of starting a grazing operation may   ask how many acres of pasture are needed for each cow. If depending   almost exclusively on pasture for their forage source, an approximation   is one-half acre per cow. Using this ratio, for 600 milk cows at least   300 acres is needed. In summer, less is needed, so excess forage can be   baled or ensiled. In late fall through spring more may be needed. If the   systems are flexible enough that a one-shot or conserved forage can be   fed during times of slow pasture growth, less than one-half acre per cow   may be needed. In any case, someone starting with grazing should stock   conservatively. Learning to manage a grazing dairy takes time, and   starting with too many cows makes the process all that more difficult.  
  &nbsp;  
    
  by L.E. Sollenberger - Institute of Food and Agricultural Sciences, University of Florida
    
  
]]></description><pubDate>Sat, 31 Jul 2010 23:32:00 +0000</pubDate><link>http://www.ruminantpro.com/ruminant-articles/range-pasture-grazing/general-guidelines-for-managing-pastures-for-dairy-cows/</link><guid>http://www.ruminantpro.com/ruminant-articles/range-pasture-grazing/general-guidelines-for-managing-pastures-for-dairy-cows/</guid><author>Sat, 31 Jul 2010 23:32:00 +0000</author><comment></comment></item></channel></rss>
