Sudangrass as companion crop to establish alfalfa

Aurora Alaguero Cordovilla

The benefits of using a companion crop over herbicides when planting alfalfa are well known. Reduced soil erosion, higher forage yields or weed control are some examples as of why to choose this strategy over herbicides. New potential companion crops were investigated in southern Quebec in order to better tolerate dry conditions. Sudangrass hybrids are drought-tolerant grasses used in forage production and can be a good candidate to use as a companion crop.

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Types of corn silage and trace minerals affect dairy production

Alvaro Garcia

Forages and their fiber have a large effect on milk production, since they constitute the largest nutrient fraction in dairy cow diets. Their chemical composition together with their physical characteristics help maintain a healthy rumen environment critical to animal health and productivity. Corn silage constitutes the main forage used in dairy cow diets in several parts of the world.

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Capítulo 7: Determinación del sexo fetal Ficha 2: Determinación de la posición del tubérculo genital

En esta ficha mostraremos como se realiza la determinación del sexo mediante la visualización del tubérculo genital, en el macho y en la hembra, en los tres planos básicos descritos anteriormente.

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Lame cows and fertility

Alvaro Garcia

According to the National Animal Health Monitoring System, lameness is the first reason for cows, losses followed by mastitis. Research has shown that nearly one-third of the total water absorbed by the hoof happens during the first hour of exposure to high moisture resulting in heavier and softer hooves. As a result, the presence of mud or accumulated manure are among the predisposing causes for cattle lameness. Hoof lesions represent 90% of lameness cases and can be divided in noninfectious lesions (e.g. sole hemorrhage, sole ulcer, or white line disease) and infectious lesions (digital dermatitis and foot rot). Insufficient bedding or poor-quality bedding can make both problems worse.

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Effect of treatment of wet brewers’ grains on microbial growth

Ishaya U. Gadzama & Alvaro Garcia

Brewers grains are the first solid material that remains after malted barley is fermented during the beer making process. Wet brewers’ grains (WBG) are often fed to dairy cattle because they provide rumen undegradable protein, soluble fiber and energy. Their storage life however is short due to their high moisture content (65 to 75%), making them susceptible to mold growth and spoilage.

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Using nano-montmorillonite modified as a mycotoxin adsorbent in dairy cattle

Andrés Haro & Alvaro Garcia

Mycotoxins are secondary metabolites produced by various species of fungi synthesized at the end of their exponential growth phase. Their presence ins in ruminant feeds can reduce growth, feed intake and negatively impact feed efficiency. In addition, they can also challenge the immune system and cause considerable economic losses.

To prevent mycotoxin contamination of feeds, preference has been given to the inclusion of montmorillonite (main constituent in bentonite) modified by a cationic surfactant to improve the adsorption capacity of mycotoxins. Reasons for this preference are its small particle size, special layered structure, porous properties and its strong ion exchange capability.

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Alternative forages: A sustainable strategy for dairies in Northern Mexico

Juan I. Sánchez-Duarte, David G. Reta-Sánchez, Esmeralda Ochoa-Martínez, Arturo Reyes González, Karla Rodríguez-Hernández, and Damián Torres-Hernández

Forages are the most important component in dairy cows’ diets because they are a source of nutrients and effective fiber. These contribute dramatically to the consumption of dry matter and nutrients; in addition to maintaining normal rumen functioning in animals. The inclusion of forage in diets for dairy cattle can vary from 40 to 80% on a wet basis.

The main forages used in dairy farms in Mexico are corn and sorghum silages, hay or alfalfa silage, and small grain cereals. Due to heat stress and reduced water availability caused by climate change, the yield and nutritional quality of these forages will be threatened in the future. It is therefore necessary to find alternative crops with good forage yields, and high nutritional quality that grow under these conditions and contribute to the sustainability of the dairy industry in Mexico.

Climate change and its effect on forages

Main problems associated with climate change that significantly affect the production of forages in the country are the increase in temperature and water shortages. Mexico is highly vulnerable to the impacts of climate change and it is expected, with 50% probability, that average temperatures will increase around 1.5 to 2˚C by 2100 (SEMARNAT-INECC, 2016). This change will not affect all states equally, since it has been reported that the Atlantic Ocean region and the north of the country are where temperatures have increased most rapidly (Greenpeace, 2010). It can be expected for prolonged drought events to occur. In the Region Lagunera for example, one of the main dairy areas in Mexico, an increase in the average annual temperature has been observed during the last 43 years (Figure 1). Additionally, precipitation has been irregular and has shown a decrease from 1988 to 2018, with was one atypical year (2003) that had around 700 mm of rain (Figure 2). Low rainfalls associated with low groundwater recharge due to runoff, have caused an imbalance between replenished groundwater and the one extracted from the main aquifers of the Region Lagunera (Figure 3; CONAGUA, 2015). Therefore, the increase in environmental temperature and the over usage of water for irrigation purposes is seriously affecting forage production and the sustainability of milk production in this region.

Figure 1. Average annual temperature from 1975 to 2018 in the Region Lagunera, Mexico.

Figure 2. Average annual rainfall from 1975 to 2018 in the Region Lagunera, Mexico.

Figure 3. Extraction and recharge of groundwater in the main aquifers of the Region Lagunera, Mexico during 2015.

Both high temperatures and water insufficiency significantly affect crops growth and development. Sustained high temperatures for several days or an extreme increase for just a few hours can negatively affect pollination, grain filling, and photosynthesis (Hatfield and Prueger, 2015). Temperatures above 35˚C have been shown to reduce pollen viability and the photosynthetic rate in cereal grains such as corn (Barnabas et al., 2008). On the other hand, the availability of water either through precipitation or irrigation is the most important factor for forage production. Water shortages during critical developmental stages also affect the same reproductive processes caused by high temperature stress (Cakir, 2004). In either case, whether stress due to high temperatures or lack of water, forage dry matter yields are seriously reduced.

High temperatures also influence forage quality. Crops grown under high temperature conditions usually accelerate their maturity, which enhances lignification of plant cell walls, and consequently affect forage nutritional value by reducing fiber digestibility (Van Soest, 1994). Corn silages with higher concentration of lignin, fiber and protein, and low starch content, could suggest high temperature stress (Ferreira and Brown, 2016). This is the result of a higher metabolic activity, where the photosynthetic pathway prioritizes the synthesis of structural plant components (cell walls), and reduces soluble carbohydrate contents (Van Soest et al., 1978).

The effects of a water restriction on forage nutritional quality have also been widely studied. Crude protein and fiber concentrations were decreased in alfalfa grown under water stress conditions (Abid et al., 2016). The reduction in crude protein was related to lower nitrogen availability, which was to either the result of low mineralization of this element in the soil, or perhaps a decrease in the transport of nitrogen from the roots to the shoots. The decrease in fibrous fractions could be associated with a lower incorporation of carbon into the cell wall, which delays maturity and promotes a greater leaf-stem ratio (Van Soest, 1994). Other forage quality parameters such as nitrate accumulation, which threatens livestock, or a reduction of soluble carbohydrates in the foliage, essential for optimal silage fermentation, are negative effects resulting from drought.

In general, higher temperatures and dry conditions will negatively affect production and quality of traditional forages in dairy farms. A practical alternative to this problem could be the use different forages which allow for the development of new forage production systems with good dry matter yields, acceptable nutritional quality, and greater adaptation to climate change.

Alternative forages in dairy farms

Finding alternative crops with agronomic characteristics that will allow quantity and quality forage to be produced in adverse high temperature conditions and lower water availability, is the most practical option in the short term in Mexico. In the Region Lagunera agronomic research has been carried out to identify alternative forage crops with production potential during the autumn-winter and spring-summer cycles. A total of around 16 forage species have been evaluated at the present time (Reta et al., 2008). Of these crops, soybeans associated with corn to improve forage nutritional composition (Reta et al., 2010a), in addition to canola and safflower since their need less water but produce a forage with high nutritional value (Reta et al., 2010b), have been the most promising plant species. These crops have also demonstrated the capacity to increase water productivity annually when they are included in traditional crop patterns such as corn and oats (Reta et al., 2015). Moreover, the planting method (Reta-Sánchez et al., 2016a) and population density (Reta-Sánchez et al., 2016b) for canola have been studied. Validation plots were also conducted to test the yield potential of this crop as a forage with a greater efficiency in the use of water compared to oats (Reta et al., 2016).

Corn soybean-silage

3 Romero Dairy Farm

Canola silage

Lanchares Dairy Farm

 

The preservation as silage of alternative forage crops and their use in dairy cattle feeding have also been evaluated and validated in commercial dairy farms. It was found that using canola, from sowing to its preservation in the silo, was carried out without problems using the agricultural equipment and materials commonly used to make silage of traditional crops (Sánchez et al., 2011). In fact, when canola silage was experimentally compared with alfalfa haymaking, it was found that the fermentative and nutritional quality characteristics both with and without microbial inoculation was similar (Table 1; Sánchez et al., 2014). Canola silage however has shown better fermentation and nutritional quality characteristics when compared to oats and triticale silage (Sánchez et al., 2011). Canola silage had lower pH and a better volatile fatty acid profile than oats and triticale silages. Similarly, canola silage had higher CP contents and energy (estimated) than oats and triticale silages (Table 2). The NDF content was lower in canola silage than in oat and triticale silages.

Table 1. Nutrient composition and fermentation of canola silage and alfalfa haylage with and without microbial inoculation under experimental conditions.

 Canola Alfalfa
 

Item

With inoculantWithout  Inoculant With inoculantWithout  Inoculant
Nutrient composition, % of DM
  DM, % of silage or haylage34.6534.7848.1545.63
  Protein25.9925.8827.0827.31
  NDF23.5023.2829.0328.08
  NFC31.5932.0529.3529.76
  TDN59.8260.2761.0861.89
  NEL, Mcal/kg DM  1.48  1.47  1.49  1.51
Fermentation, % of DM
  pH4.24.25.04.4
  Amonia-N, % of total N12.1811.398.010.30
  Lactic acid12.6811.28  7.4511.75
  Acetic acid11.04  9.4710.3112.19
  Propionic acid  7.40  0.00  2.19  3.03
  Butiric acid  0.00  0.00  0.00  0.00

Microbial inoculation: 10 g/t of ensiled forage 

Table 2. Nutrient composition and fermentation of canola, oat, and triticale in a commercial dairy farm.

 Silage
ItemCanolaOatTriticale
Nutrient composition, % of DM
  DM, % of silage40.8637.4339.07
  Protein20.3516.4315.35
  NDF33.3754.2157.95
  NFC27.1914.7912.43
  TDN54.1249.1647.28
  NEL, Mcal/kg of DM  1.28  1.11  1.03
  NEM, Mcal/kg of DM  1.24  1.00  0.90
  NEG, Mcal/kg of DM  0.67         0.45 0.36
  ME, Mcal/kg of DM  2.09  1.84  1.74
Fermentation, % of DM
  pH4.3  5.04  4.62
  Amonia-N, % of total N12.7522.7718.17
  Lactic acid16.69  8.65  7.59
  Acetic acid  3.82  3.08  3.52
  Propionic acid  1.66  4.91  5.26
  Butiric acid  0.00  0.54  0.00

When canola silage was used to replace oats silage in growing Holstein heifer diets, there was no difference in average dry matter intake (Sánchez et al., 2011). A second test was conducted in 2012 to evaluate the effects of replacing oat silage with canola silage on feed intake and daily weight gains in 7 to 9-month-old Holstein heifers. The diet with canola silage had more protein and energy and less NDF than the oats silage diet (Table 3). In general, it was observed that heifers fed the canola silage diet consumed on average 0.2 kg/day more dry matter than those that received the oats silage diet (Figure 4). This resulted in greater daily weight gains in the heifers fed the diet with canola silage (Figure 5). Increases in dry matter intake and weight gains in heifers fed canola silage could be associated with lower fiber concentrations and higher protein and energy contents compared to the oat silage diet.

Table 3. Ingredient and nutrient composition of diets containing canola and oat silage in a commercial dairy farm.

 Diet
ItemCanola Oat
Ingredients, % of DM
  Sorghum silage49.5549.55
  Canola silage39.06
  Oat silage39.06
  Corn Straw  2.50  2.50
  Soybean meal solvent extracted 48% CP  8.29  8.29
  Mineral premix  0.60  0.60
Nutrients, % of DM
  DM, % of diet35.6934.61
  Protein         16.70                 15.20
  ADF35.0037.50
  NDF46.5054.30
  NFC27.5020.10
  Ether extract  2.50  3.20
  Ca  0.80  0.40
  P  0.40  0.41
  Mg  0.30  0.25
  K  2.14  2.89
  S  0.22  0.19
  ME, Mcal/kg of DM  2.21  2.06
  NEG, Mcal/kg of DM  0.76  0.64

Figure 4. Dry matter intake of Holstein heifers fed diets containing canola and oat silage.

Figure 5. Average daily gain of Holstein heifers fed diets containing canola and oat silage.

Corn-soy silages have also been evaluated commercially. Sánchez et al. (2012) conducted a test to validate the effects of adding three different silages to the diets of lactating Holstein cows: 1) corn and soy were sown separately then ensiled on a 50:50 ratio (50:50 corn-soy), 2) the corn-soy silage crop was planted alternating one row of corn and one row of soybeans, and 3) straight corn silage only. There were no difficulties observed making silages with the equipment used to ensile traditional crops. The corn-soy silage (50:50) had higher pH and ammonia nitrogen compared to the other two silages. This suggested the soy forage acted like a buffer and that there was protein degradation in the silo. Crude protein was higher in the 50:50 corn-soy silage, but NDF and ADF concentrations were lower (Table 4). It was found that the interspersed corn-soy planted silage and the straight corn silage had better fermentation compared to the 50:50 corn-soy silage. Regarding the cost of silage production, it was less expensive to produce intercropped corn-soybean silage ($0.63 / kg as offered) than 50:50 corn-soy silage ($0.86 / kg as offered) and straight corn silage ($0.71 / kg as offered). This same cost trend was observed for protein and energy contents among silages.

When these silages were included in the diet of lactating Holstein cows, higher protein content and lower NDF concentrations were observed in the diets with silage from interspersed corn-soy and the straight corn silage than in the diet containing 50:50 corn-soy. In addition, the 50:50 corn-soy association silage diet had less NFC and energy contents compared to the other two diets (Table 5). When feeding cows with diets containing corn-soy silages, a higher DM intake was observed in cows fed diets containing silage from interspersed planted corn-soy and straight corn silage compared to cows fed 50:50 corn-soy (Table 6). This could be since the higher concentration of ammonia nitrogen from 50:50 corn-soybean silage restricted intake. However, milk production was higher when cows were fed the diet containing interspersed corn-soy silage compared to the diets formulated with the 50:50 corn-soy and straight corn (Table 6). These effects were reflected in higher income from milk sales and a considerable profit margin when the interspersed corn-soy silage was included compared to the other two diets (Table 6; Sánchez et al., 2012). Milk composition was similar when cows were fed diets that included the three types of silages.

Table 4. Nutrient composition, fermentation, and cost of corn-soybean silage and corn silage in a commercial dairy farm.

 Silage
 

Item

Corn-soybean 

(50:50)

Corn-soybean  associated 

Corn

Nutrient composition, % of DM
  DM, % of silage37.1527.8723.59
  Protein13.0410.9710.44
  NDF56.1448.9357.33
  ADF44.3133.0435.93
  NFC18.4330.3823.30
  TDN46.3060.6252.10
  NEL, Mcal/kg of DM  0.98  1.37  1.14
  NEM, Mcal/kg of DM  0.83  1.37  1.05
  NEG, Mcal/kg of DM  0.29  0.79  0.50
  ME, Mcal/kg of DM  1.66  2.22  1.89
Fermentation, % DM
  pH 4.64.23.8
  Amonia-N, % of total N13.14  8.20  7.40
  Lactic acid42.8344.7051.93
  Acetic acid47.2335.4040.33
  Propionic acid  0.000.0  0.00
  Butiric acid  0.000.0  0.00
Silage cost, $/kg
  As-fed silage  0.86  0.63  0.71
  Silage as DM basis  2.45  1.81  2.02
  CP18.8016.4819.39
  NEL, $/Mcal  2.50  1.32  1.78

Table 5. Ingredient and nutrient composition of diets containing corn-soybean silage in a commercial dairy farm.

 Diet
 

Item

Corn-soybean 

(50:50)

Corn-soybean  associatedCorn
Ingredients, % of DM
  Alfalfa hay25.7826.7027.14
  Alfalfa silage13.0713.5413.76
  Sorghum silage28.8129.8430.34
  Corn silage  9.19
  Corn-sobean silage13.7510.67
  Cottonseed  8.628.93  9.08
  Concentrate (LALA®)  9.9310.2910.46
Nutrients, % of DM
  DM, % of diet42.6745.2942.97
  Protein17.2318.1619.46
  ADF54.6145.6847.81
  NDF37.9031.5030.75
  NFC  9.9322.4025.01
  Ether extract  2.50  2.50  2.50
  Ca  1.10  1.10  1.10
  P  0.54  0.50  0.50
  Mg  0.34  0.35  0.35
  K  1.98  2.01  2.00
  S  0.24  0.25  0.25
  NEL, Mcal/kg of DM  1.15  1.32  1.30

Table 6. Lactation performance and income of cows fed diets containing corn-soybean silage in a commercial dairy farm.

 Diet
 

Item

Corn-soybean 

(50:50)

Corn-soybean 

associated

 

Corn

Performance and economic income
  DMI, kg/d   17.84 19.44 18.65
  Cost, $/DM intake   78.26  78.78  80.21
  Milk, L/d   20.80  21.67  20.65
  Income , $/d116.48121.35115.16
  Margen, $  38.22  42.58  35.43
Milk components, %
  Fat   3.63   3.62   3.64
  Protein   3.24   3.31   3.31
  Lactose   7.48   4.81   4.74
  Total solids12.24 12.46 12.38

            †Estimated with DMI and income for milk sell considering a price of $5.60/L of milk.

 In conclusion, it is possible to find alternative forages in the future that adapt to milk production systems and adverse weather conditions in Mexico. However, there are other needs that should be considered to successfully introduce alternative forages to these production systems in the country.

Implications

Although it has been shown that there are some crops with forage potential that use less water and are better adapted to climate change, it is still necessary to expand agronomic and preservation research info in other forage species. Silage tests should be performed to evaluate silage compaction, optimum DM of the forage at ensiling time, and effect of different microbial inoculants on the parameters of fermentation and nutritional quality of the silage. Additionally, there is a need to research in greater depth the effects of alternative crop silages already explored on nutrient fermentation and digestibility, DM intake, milk production, and milk composition. Validation plots must be established with these species to demonstrate their production potential, quality, and adaptation in dairy farms, together with seed, agrochemicals and microbial inoculants companies. As a result, dairy producers will be able to adopt and use alternative crops to promote future milk production sustainability in Mexico.

About the authors

The authors are researchers in dairy cattle nutrition and forage quality at the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias. Campo Experimental La Laguna. Matamoros, Coahuila, México 27440.

References:

Abid, M., Mansour, L.E., Yahia, K.B., Bachar, A., Khaled, B., Ferchichi, A. 2016. Alfalfa nutritive quality as influenced by drought in South-Eastern Oasis of Tunisia, Italian J. Anim. Sci. 15(2):334-342.

Barnabas, B., Jäger, K., Féher, A. 2008. The effect of drought and heat stress on reproductive processes in cereals. Plant Cell Environ. 31(1):11-38.

Cakir, R. 2004. Effect of water stress at different development stages on vegetative and reproductive growth of corn. Field Crop Res. 89:1-16.

CONAGUA (Comision Nacional del Agua). Corte al 2015. 3ras jornadas técnicas de gestión de acuíferos y recarga artificial. Acuíferos críticos del territorio nacional. Torre de Ingeniería UNAM. 26 de abril del 2019.

Ferreira, G., Brown, A.N. 2016. Advances in silage production and utilization. Chapter 2: Environmental factors affecting corn quality for silage production. ISBN 978-953-51-2777-2. INTECH. 39-51.

Greenpeace. 2010. México ante el cambio climático. Evidencias, impactos, vulnerabilidad y adaptación. p. 69.

http://paginas.facmed.unam.mx/deptos/sp/wp-content/uploads/2013/12/vulnerabilidad-mexico.pdf

Hatfield, J.L., Prueger, J.H. 2015. Temperature extremes: Effect on plant growth and development. Weather and Climate Extremes. 10:4-10.

Reta, S.D.G., Figueroa, V.U., Serrato, C.J.S, Quiroga, G.H.M., Gaytán, M.A., Cueto, W.J.A. 2015. Potencial forrajero y productividad del agua en patrones de cultivos alternativos. Rev. Mex. Cienc. Pecu. 6(2):153-170.

Reta, S.D.G., Serrato, C.J.S., Gaytán, M.A., Quiroga, F.H.M., López, S.F., Ordaz, V., Godoy H.J. 2016. Validación de patrones de cultivo forrajeros alternativos con menor estrés por altas temperaturas en la Comarca Lagunera. AGROFAZ 16(1):65-75.

Reta, S.D.G., Serrato, C.J.S., Figueroa, V.R., Cueto Wong, S.J.A., Berumen P., Santamaria C.J. 2008. Cultivos alternativos con potencial de uso forrajero en la comarca lagunera. INIFAP. Libro técnico # 3. 1er edición. ISBN 978-607-425-042-8. p. 268.

Reta, S.D.G., Espinosa S.J.T., Palomo, G.J.S.A.. Serrato, C., Cueto, W.J.A., Gaytán, M.A. 2010a. Forage yield and quality of intercropped corn and soybean in narrow strips. Spanish. J. Agric. Res. 8(3):713-721.

Reta, S.D.G., Figueroa V.U., Faz C.R., Núñez H.G., Gaytan M.A., Serrato, C.J.S., Payan, G.J.A. 2010b. Sistemas de producción de forraje para incrementar la productividad del agua. Rev. Fitotec. Mex. 33(4):83-87.

Reta-Sanchez, D.G., Serrato-Corona, H.J.S., Quiroga-Garza, A.M., Gaytan-Mascorro, Figueroa-Viramontes, U. 2016a. Forage yield and chemical composition of canola (Brassica napus L.) as affected by sowing methods. Grass Forage Sci. 71:281-290.

Reta-Sánchez, D.G., Serrato-Corona, H.J.S., Quiroga-Garza, U.M., Figueroa-Viramontes, A. Gaytán-Mascorro y Cueto-Wong J.A. 2016b. Respuesta de canola para forraje a la densidad de población. Rev. Fitotec. Mex. 39(3):253-258.

Sánchez, D.J.I., Serrato, C.J.S., Reta, S.D.G., Ochoa, M.E., Reyes, G.A. 2014. Assesment of ensilability and chemical composition of canola and alfalfa forages with or without microbial inoculation. Indian. J. Agric. Res. 48(6):421-428.

Sánchez, D.J.I., Reta, D.G., Torres, D.H., Ochoa, M.E., Alfonso Nava. 2012. Ensilado de maíz-soya como forraje alternativo en la alimentación de ganado lechero. Hoard‘s Dairyman en Español. ISSN 1079-2007. #215, 676-679.

Sánchez, D.J.I., Reta, S.D.G., Ochoa, M.E., Serrato, C.J.S. 2011. Ensilado de canola, una nueva alternativa forrajera en la alimentación del ganado lechero: Primeras pruebas realizadas en la Comarca Lagunera. Hoard‘s Dairyman en Español. ISSN 1079-2007. #201, 582-584.

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Urine biomarkers of subclinical mastitis in dairy cows

Alvaro Garcia

Mastitis continues to be one of the top two health issues (lameness is the first) in US dairy farms, and one of the main culling reasons. Mastitis is the result of either contagious or environmental bacteria causing inflammation in the udder. Contagious bacteria are spread from a cow with an infected udder to a healthy cow. Environmental bacteria come from the cow’s environment (bedding, soil, manure, etc.) and thus are highly influenced by management practices.

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Inclusion of clay as a supplement in the diet of dairy cattle

Andrés Haro & Alvaro Garcia

Farmers have been using clay as a feed additive in dairy cow diets for quite some time, both to reduce aflatoxin toxicity and rumen acidosis. Clay buffers rumen pH thanks to its high ion exchange capacity, leading to reduced acidification of the rumen contents which improves fiber degradability.

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Capítulo 7: Determinación del sexo fetal Ficha 1: ¿Cómo y cuándo se realiza la determinación del sexo fetal?

El sexo de los terneros recién nacidos tiene un gran impacto en la productividad de las explotaciones de ganado vacuno1, 2. En el caso de las granjas de vacuno lechero, las hembras son necesarias para reemplazar a las vacas eliminadas cada año, cuyo porcentaje se encuentra entorno al 30%. Los machos, en este caso tendrán menor valor que las hembras. Aunque, si hablamos de producción de carne, el valor de los machos aumenta por el mayor peso alcanzado por estos. En cualquier caso, conocer de antemano el sexo de los terneros que nacerán en la explotación nos permitirá una mejor gestión de la reproducción.

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