Milk Yield Potential Research Articles

An easy decision-making graphic tool to improve herd level milk yield in a local scale dairy farming system

Several features prevent dairy farms from reaching their full potential milk yield levels. A plurality of methods are available to analyse a farm’s yield gap, but in practice, farmers rarely use them to understand their main constraints to production. We propose a simple and graphical approach to tune the limiting (feed-related) or reducing (management-related) factors to evaluate the likelihood of being a high-yielding farm. We gathered data from 32 farms within a local-scale dairy system in Northern Italy. Data regarded milk yield (MY), dry matter intake (DMI), feeding ration’s homogeneity index (Hi), feed sorting (Si) index, ration’s geometric mean particle length (GMPL), ration digestibility, income over feed cost (IOFC) and MY summer-winter ratio (SWR). Farms were classified according to their MY levels into high (H) and low or medium (L + M), with a 36.7 kg × cow−1 day−1 threshold. At an ANOVA model for MY class, H farms resulted in higher IOFC (p < 0.001), GMPL (p = 0.046), DMI (p = 0.006), digestible DM (DDM, p = 0.013), digestible crude protein (DCP, p = 0.011), digestible starch (Dstarch, p = 0.001), and feed efficiency (FE, p = 0.003). At a logistic AIC stepwise regression, the GMPL (odds = 6.528, 95% CI = 1.11-64.2) and DMI (odds = 3.889, 95% CI = 1.43-16.5) favoured farms being classified in the H production class. The nomogram was used to calculate a confusion matrix, achieving an overall accuracy of 0.70, demonstrating its ability to transform predictive models into a graphical, realisable tool.

Factors Influencing Milk Yield During Lactation of D’man Ewes in its Cradle in Algeria

Abstract A study was conducted at the National Institute of Agricultural Research (Adrar station) between 2017 and 2019 to assess the milk yield potential of prolific D’man ewes. A total of 210 daily milk production records from (of) 21 D’man ewes were collected during three successive lambings with the weighing method before and after feeding followed by manual milking. In addition, the effects of birth type, lambing rank, birth season and weight of ewes to the struggle (at breeding) on milk production were analyzed. The least-squares averages of daily and total milk production of D’man ewes were 0.85 ± 0.03 kg and 59.1 ± 0.96 kg, respectively, and the highest daily milk yield was observed in the second week of lactation. Ewes suckling more than two lambs had the highest milk yield. Indeed, ewes with triplets or more (+57.3%) and twins (+22.1%) have a significantly higher milk yield (P&lt;0.01) than ewes nursing single lambs. The effect of the other factors was not significant on milk production of D’man ewes. It can be concluded that increasing the quantity of milk produced per ewe according to the number of lambs suckled will help to make the most of multiple lambings thanks to a low mortality rate and improved growth, especially during the first month of lactation.

THE INFLUENCE OF FEMALE ANCESTORS ON MILK PERFORMANCE IN FIRST- CALF COWS OF THE HOLSTEIN BREED DAIRY CATTLE OF DOMESTIC SELECTION

The results of studies on the influence of female ancestors on the milk performance in first-calf cows of the Holstein breed of dairy cattle of domestic selection are presented. The highest values of milk yield, the amount of milk fat and protein, as well as the mass fraction of protein in milk were observed in daughters whose mothers’ milk yield was over 10,000 kg and amounted to 9295 (p≤0.01), 341.3, 313.3 (p≤0.01) kg, 3.37% (p≤0.05), respectively. First-calf cows with a milk yield of MM 9001-9500–9227 kg (p≤0.001) have a high degree of abundant milk production. They also had the highest amount of milk fat and protein, which amounted to 344.8 (p≤0.01) and 309.4 (p≤0.001) kg, respectively. The highest milk yield, milk fat and protein content were in first-calf cows with a milk yield of MF over 14.000 kg. The realization of the genetic potential for milk yield over 305 days of lactation was 102.1%.

Realization of the genetic potential of Yaroslavl cows

The purpose of research was determining the degree of realization of the genetic potential of Yaroslavl cows of different genotypes. It was found out that the formation of productive traits in improved genotypes and purebred animals is different. The genetic potential of cows of the improved genotype of the Yaroslavl breed in milk yield exceeded purebred animals by 2,460 kg or by 51.9%. Milk yield of cows of the improved genotype were higher by 718-1574 kg than those of purebred Yaroslavl cattle, however, the degree of realization of the genetic potential was lower and amounted to 55.2-76.8%. Purebred cows of the Yaroslavl breed had a high degree of realization of the genetic potential for milk yield throughout the entire productive use - 68.0-82.2%, which indicates their better adaptive ability to the conditions of feeding and maintenance.

32 Feeding Gilts and Sows to Maximize Their Mammary Development

Abstract The task of feeding growing replacement gilts, gestating gilts and sows to maximize their future milk yield is not easy. Yet, this is particularly important when considering the great demands made by the large litters of our current hyperprolific sow genetic lines. One aspect that needs to be considered is the effect of feeding on mammary development taking place before the onset of lactation, which is a major determinant of potential milk yield. One can only attempt to stimulate mammogenesis during periods with rapid mammary development. In swine, these periods are from three months of age until puberty, from 90 days of gestation until farrowing, and throughout lactation. Early studies showed that a 20% or 26% feed restriction from 90 days of age until puberty drastically reduces mammary parenchymal tissue mass. However, in a more recent study, sow milk yield was not altered following a 10% or 20% feed restriction, or a 25% dietary fiber addition (diluting dietary energy by 5%) from 90 days of age to breeding. This absence of effect may be due to the greater feed intake of control gilts in that recent study compared with the older studies. Such a difference in feed intake was likely brought about by genetic selection for faster growing pigs, and it appeared that feed intake of growing gilts can be reduced to 2.7 kg/day without detrimental effects on their future milk yield. During prepuberty, inclusion of the phytoestrogen genistein (2.3 g/day) in the diet increases the number of mammary parenchymal cells. During late gestation, feeding very high energy levels (10.5 Mcal ME/day) may have detrimental effects on mammary development and subsequent milk production. Furthermore, feed intake throughout gestation is important because of its effect on body condition. Gilts that are too thin (&amp;lt; 16 mm backfat thickness) in late gestation have reduced mammary development. A 40% increase in SID Lys via inclusion of additional soybean meal to the diet of gilts from days 90 to 110 of gestation increased mammary parenchymal mass by 44%. On the other hand, providing the same 40% increase in dietary SID Lys to multiparous sows during late gestation had no significant effect on mammary parenchymal mass. These findings therefore support the use of phase-feeding during gestation of gilts only. Increasing circulating concentrations of the growth factor IGF-1 during late gestation also increased mammary parenchymal mass by 22%. Current data clearly demonstrate that feeding management before lactation can be used to improve sow milk yield.

AVALIAÇÃO DA PRODUTIVIDADE E VALOR NUTRITIVO DE MILHO PARA SILAGEM NO ESTADO DE SÃO PAULO NA SAFRA 2022/2023

he objective of this work was to evaluate the mass yield for silage, its nutritive value and the grain yield of 15 maize cultivars. The experiments were carried out in the 2022/2023 harvest, in Mococa, Tatuí and Votuporanga. There were plots of six lines of five meters, with four replications, in a randomized block design. There was interaction (p&gt;F) between cultivars and locations for plant height (AP), dry matter yield (PMS), grain yields at ensilage (PGS) and at maturity (PGM), starch content, acid detergent fiber (FDA) and neutral detergent fiber (FDNom). It is interesting to note that the cultivar AG 8701 PRO3 showed a high potential for milk yield per hectare in the three locations, indicating its productive stability in different soil and climate conditions, while other cultivars performed differently depending on the environment. The average dry matter productivity was 20.99 t.ha-1 in Mococa, 19.06 t.ha-1 in Tatuí and 15.38 t.ha-1 in Votuporanga. The grain productivity at the time of ensiling was 8.49, 7.00 and 6.23 t.ha-1 for Mococa, Tatuí and Votuporanga, respectively, these grains being of great importance in the nutritional value of the forage, due to the presence of starch, positively influencing milk yield per ton of dry matter. Keywords: Starch, fiber, Milk, TDN, Production.

Random regression models to estimate genetic parameters for milk yield, fat, and protein contents in Tunisian Holsteins.

This study aimed to find the parsimonious random regression model (RRM) to evaluate the genetic potential for milk yield (MY), fat content (FC), and protein content (PC) in Tunisian Holstein cows. For this purpose, 551,139; 331,654; and 302,396 test day records for MY, FC, and PC were analysed using various RRMs with different Legendre polynomials (LP) orders on additive genetic (AG) and permanent environmental (PE) effects, and different types of residual variances (RV). The statistical analysis was performed in a Bayesian framework with Gibbs sampling, and the model performances were assessed, mainly, on the predictive ability criteria. The study found that the optimal model for evaluating these traits was an RRM with a third LP order and nine classes of heterogeneous RV. In addition, the study found that heritability estimates for MY, FC, and PC ranged from 0.11 to 0.22, 0.11 to 0.17, and 0.12 to 0.18, respectively, indicating that genetic improvement should be accompanied by improvements in the production environment. The study also suggested that new selection rules could be used to modify lactation curves by exploiting the canonical transformation of the random coefficient covariance (RC) matrix or by using the combination of slopes of individual lactation curves and expected daily breeding values.

The role of animal breeding in productivity growth: Evidence from Wisconsin dairy farms

AbstractWe examine the relationship between investments in animal breeding and productivity growth on Wisconsin dairy farms using a control function approach. We incorporate farm‐level annual investment in breeding and genetics into the law of motion of productivity as in De Loecker (2013) to test the relationship between these investments and realized productivity. Our unique dataset also allows us to look at the effect of choosing bulls with high milk yield potential on productivity. Our results indicate that breeding investments made 3 years prior are associated with higher productivity of the current cohort. However, the farms with the highest level of productivity reap the lowest benefits from breeding investments, suggesting that there are diminishing returns to investing in genetics. When milk output is not quality adjusted, the contribution of breeding to productivity is undetectable, suggesting that breeding and investments in milk quality are related. We conclude that investments in breeding and genetics significantly contribute to dairy farm productivity, especially in terms of milk quality.

ГЕНЕТИЧЕСКИЙ ПОТЕНЦИАЛ ЧЕРНО-ПЕСТРОГО СКОТА РАЗНЫХ ЛИНИЙ И ВЕТВЕЙ

An analysis of the genealogical structure of black-and-white cattle was carried out, taking into account new promising branches in the breeding reproducers of LLC “Plemennoy edelo Alekseevskoye” and LLC “Plemennoye delo”. It has been established that the genealogical structure of the broodstock of reproducers is represented by three lines of the Holstein breed, such as Vis Beck Idiala 1013415, Reflection Sovering 198998 and Montvik Chieftain 95679. There are eight promising branches from three lines in the herd, while the largest share of dairy cattle is assigned to the branches of HANOVERHILL STARBUCK 352790 - 21.9% (“Plemennoye delo Alekseevskoye”) and 40.3% (“Plemennoye delo”) from the Vis Bek Aidiala line. Reflection Sovering has four branches in the herd “Ploomnoedelo”, and three branches in the “Plemennoye delo Alekseevskoye”, with the largest shares of TO-MAR BLACKSTAR-ET 1929410 - 13% and 14.1% and ARLINDA ROTATE 1697572 - 5.8% and 10.9%. The Montwick Chieftain line is represented by one branch - CARLIN-M IVANHOE BELL with 12.5-13.3% of cows in the herd. A small group of cattle comes from the WALKWAY CHIEF MARK 1773417 branch (3.4%).A high pedigree index of the bull is characterized by animals of the SWEET-HAVEN TRADITION branch with a milk yield of 12205 kg, the TO-MAR BLACKSTAR-ET branch (13320 kg; 4.00%; 3.35%), the WALKWAY CHIEF MARK branch (13801 kg; 4.46%) and branch CARLIN-M IVANHOE BELL (13323 kg; 4.26%; 3.38%). Animals of the M. Chieftain line with the best genetic potential for milk yield are observed to have an insufficiently high degree of its implementation, only 43%. In general, all lines have a low realization of the genetic potential of milk yield (43-49%), which is primarily due to the large number of young cows in the herd and the low age at calving.

ГЕНЕТИЧЕСКИЙ ПОТЕНЦИАЛ ЧЕРНО-ПЕСТРОГО СКОТА РАЗНЫХ ЛИНИЙ И ВЕТВЕЙ

An analysis of the genealogical structure of black-and-white cattle was carried out, taking into account new promising branches in the breeding reproducers of LLC “Plemennoy edelo Alekseevskoye” and LLC “Plemennoye delo”. It has been established that the genealogical structure of the broodstock of reproducers is represented by three lines of the Holstein breed, such as Vis Beck Idiala 1013415, Reflection Sovering 198998 and Montvik Chieftain 95679. There are eight promising branches from three lines in the herd, while the largest share of dairy cattle is assigned to the branches of HANOVERHILL STARBUCK 352790 - 21.9% (“Plemennoye delo Alekseevskoye”) and 40.3% (“Plemennoye delo”) from the Vis Bek Aidiala line. Reflection Sovering has four branches in the herd “Ploomnoedelo”, and three branches in the “Plemennoye delo Alekseevskoye”, with the largest shares of TO-MAR BLACKSTAR-ET 1929410 - 13% and 14.1% and ARLINDA ROTATE 1697572 - 5.8% and 10.9%. The Montwick Chieftain line is represented by one branch - CARLIN-M IVANHOE BELL with 12.5-13.3% of cows in the herd. A small group of cattle comes from the WALKWAY CHIEF MARK 1773417 branch (3.4%).A high pedigree index of the bull is characterized by animals of the SWEET-HAVEN TRADITION branch with a milk yield of 12205 kg, the TO-MAR BLACKSTAR-ET branch (13320 kg; 4.00%; 3.35%), the WALKWAY CHIEF MARK branch (13801 kg; 4.46%) and branch CARLIN-M IVANHOE BELL (13323 kg; 4.26%; 3.38%). Animals of the M. Chieftain line with the best genetic potential for milk yield are observed to have an insufficiently high degree of its implementation, only 43%. In general, all lines have a low realization of the genetic potential of milk yield (43-49%), which is primarily due to the large number of young cows in the herd and the low age at calving.

Management Practices and Production Constraints of Indigenous Somali Cattle Breed in Shabelle Zone, Somali Regional State, Ethiopia

This study was conducted in Shabelle zone of Somali Regional State to assess management practices and production constraints of indigenous Somali Cattle. A total of 200 household heads were selected from four cattle potential districts; Dhanan, Ber’ano, Godey & Adadle. The relevant information was collected through semi-structured questionnaire, focus group discussion, key informants interview, and personal observations. Majority of the respondents were illiterate. The average cattle holding size was 8.97 heads/household and cattle were mainly kept for milk production. The major feed resources in the study area were natural pasture and crop residue, and communal grazing was the most important feeding system in the area. Feed shortage was a problem hindering cattle production in the study area during dry season mainly January up to March. Animals traveled long distances to watering points (>5 km) during dry season, while in wet season, animals were watered in nearby water sources. Cattle housing was open kraal fenced with the thorned plenty acacia trees and calves were housed separately from other cattle. Breeding in the study area was uncontrolled and was bred with their own or neighbors’ bull. Age at first mating, age at first calving and calving interval were 3.25 years, 4.05 years and 16.56 months, respectively. The daily milk yield and lactation length were 2.22 liters and 8.07 months, respectively. The production and reproduction performance of Somali cattle was relatively higher than other local breeds in the country mainly in terms of milk yield and fertility potential under the existing environmental conditions. The major constraints of cattle production were feed shortage, disease, water scarcity, lack of veterinary services, marketing problem and predator. Among those constraints, inadequate supply of quality feed, diseases and water shortage were the main reasons for low productivity of cattle and are the major factors limiting productivity. Therefore, to sustain the production system in the study areas, it is recommended to improve the current condition of communal rangelands through management of degraded areas by awareness creation on the value of these common resources and development of rules and regulation to sustain the existing resource and implement over the utilization of communal/pastoral rangeland management systems to reduce constraints such as shortage of feed, drought and grazing land deterioration which perpetuated through time due to land-use changes and seasonal fluctuation).

Генеалогическая структура татарстанской популяции черно-пестрого скота по принадлежности к перспективным ветвям

A study was made of the genealogical structure of black-and-white cattle, taking into account new promising branches in the breeding herds of KrasnyVostok Agro JSC.The data of 14554 heads of breeding cows, which originated from 217 Holstein bulls, were studied. It has been established that the herd has eight promising branches from three lines, while the largest share in the population of dairy cattle is given to the branches of HANOVERHILLSTARBUCK 352790 (28.3%), ROCKALLI SON OF BOVA 1665634 (20.5%) from the line of Vis BekIdial and WALKWAY CHIEF MARK 1773417 (16.5%) from the line Reflection Sovering. A small group of cattle comes from the branch S-W-D VALIANT 1650414 (1.2%). The animals of the TO-MAR BLACKSTAR-ET branch with a milk yield of 13059 kg, the mass fraction of fat in milk – 4.21% and the mass fraction of – 3.29% are characterized by a high bull parent index of the bull and branch WALKWAY CHIEF MARK (12213 kg – 4.28% – 3.25%). Animals of the R. Sovering line with the best genetic potential for milk yield are not observed to have a sufficiently high degree of its implementation.Thus, all lines have a low realization of the genetic potential of milk yield, which is primarily associated with a large number of young cows in the herd and a low age at calving.

Realization of the potential of cows of Holstein breed of different generations in terms of productive traits

Breeding work with dairy cattle in the Kurgan region is aimed at breeding animals that combine the adaptive properties and valuable traits of cattle of Black-and-White breed with a high proportion of genes of Holstein breed. Such animals are characterized by high productivity and suitability for intensive technology of their housing. The purpose of the research was to determine the indicators of milk productivity of first-calf heifers of different generations of Holstein breed, imported to the pedigree farms of the Kurgan region, as well as to determine the degree of realization of the genetic potential of animals. Scientific research has been carried out in the herd of CJSC “Glinka” (Kurgan), where highly productive cattle of Black-and-White and Holstein breeds are bred. The subject of research was the first-calf heifers of the imported Holstein breed of German selection of different generations, as well as the herdmates of Black-and-White breed. It has been found that the realization of the genetic potential for milk yield in Holstein cows of German breeding was higher and amounted to 76,4 %, in cows of Black-and-White breed 69,9 %. The highest milk yield for 305 days of lactation has been observed in the second generation of Holstein heifers 8905 kg, which exceeded the milk yield of herdmates of the second and third generations by 113 kg or 1,26 % and 174 kg or 1,95 %, respectively. The mass fraction of fat in German Holsteins of different generations ranged from 3,99 to 4,21 % (P &lt; 0,001), while the mass fraction of protein in the milk of first-calf heifers varied slightly in the range from 3,18 to 3,20 %. In terms of live weight, the animals of the third generation slightly exceeded the herdmates of the 1st and 2nd generations by 19 kg or 3,25 % and 20 kg or 3,43 %, respectively. The largest profit has been received from the first-generation first-calf heifers of Holstein breed of German selection, where the level of profitability of milk production was 50,7 %, which was higher than that of the herdmates of the second and third generations by 3,9 and 7,9 %, respectively.

Evaluation of Non-linear Models to Predict Potential Milk Yield of Beef Cows According to Parity Order Under Grazing.

This study aimed to evaluate the effect of parity order on milk yield (MY) and composition over time of grazing beef cows and to evaluate non-linear models to describe the lactation curve. Thirty-six pregnant Nellore cows (12 nulliparous, 2 years; 12 primiparous, 3 years; and 12 multiparous, 4–6 years) were included in the study. With calving day assigned as day 0, milking was performed using a milking machine to estimate MY on days 7, 14, 21, 42, 63, 91, 119, 154, and 203. Dummy variable analyses were applied to estimate its effects on MY, composition (kg and percentage), afternoon/morning, and afternoon/total proportions. Since multiparous cows had higher MY than nulliparous and primiparous cows, two different groups were used for lactation curve analysis: Mult (multiparous) and Null/Prim (nulliparous and primiparous). The MY estimated by the last edition of BR-Corte (Nutrient Requirements of Zebu and Crossbred Cattle) equation was compared with the observed values from this study. Five nonlinear models proposed by Wood (WD), Jenkins & Ferrell (JF), Wilmink (WK), Henriques (HR) and Cobby & Le Du (CL) were evaluated. Models were validated using an independent dataset of multiparous and primiparous cows. The estimates for parameters a, b, and c of the CL equation were compared between groups, and the BR-Corte equation used the model identity methodology. Nulliparous and primiparous cows displayed similar MY (P > 0.05); however, multiparous cows had an average MY that is 0.70 kg/day greater than that of nulliparous and primiparous cows (P < 0.05). Milk protein and total solids were higher for multiparous cows (P < 0.05). Effect of days in milking was found for milk fat, protein, and total solids (P < 0.05). The yield of all milk components was higher for multiparous cows than for nulliparous and primiparous cows. The afternoon/morning and afternoon/total proportions of milk production were not affected by parities and days in milking (P > 0.05), with an average of 0.76 and 0.42, respectively. The BR-Corte equation did not correctly estimate the MY (P < 0.05). The equations of WD, WK, and CL had the best estimate of MY for both Mult and Null/Prim datasets. The equations had a very similar Akaike's information criterion with correction and mean square error of prediction.

Diet selected by goats on xerophytic shrubland with different milk yield potential

We hypothesized that diet choice of mixed-breed goats on xerophytic shrubland of northern Mexico depends on their milk yield potential. During winter and spring (dry season), milk yield was recorded and forage samples were collected weekly. Goats were separated into a medium (MP; n = 20) or low-milk yielding groups (LP; n = 20). Total milk yield for 105 d lactation was 45.2 ± 12.5 and 20.7 ± 5.2 L for MP and LP goats, respectively. Dam bodyweight was positively related to milk yield (P < 0.001). Microhistological analyses showed that goat diets were composed mainly of shrubs (33%) and perennial grasses (36%) during the dry season with no influence of milk-yield or season on diet selection. Plants with abundant secondary compounds such as Larrea tridentate and Prosopis laevigata constituted around 7% of the goat diets in winter. Goats showed strong selectivity for Bouteloua gracilis and Croton lechleri in both seasons. The energy content of forage selected by MP goats was higher (P < 0.01) than that of LP goats. CP content of forages selected by goats was higher (12.7%; P < 0.01) in spring than in winter (8.1%). We concluded that mixed-breed goats with higher milk yield capacity selected similar diets as goats with less milk production capacity during both seasons. These mixed-breed goats reared on xerophytic shrubland of northern Mexico have the potential for producing moderate levels of milk during winter and spring (dry season); however, concentrate supplementation is necessary to sustain milk production under condition of forage scarcity.

Can on-farm animal welfare explain relative production differences between dairy herds?

AbstractThe aim of this study was to investigate factors responsible for between-herd variation in milk production, when genetic variation is controlled. Quantitative information regarding farms’ production environment and animal welfare, as evaluated annually by veterinarians and health and feeding records, were the factors studied. Principal component analysis was used to reduce the production environment variables as well as the welfare data. Two linear regression models were devised. The first model used welfare indicators and veterinary treatments to predict the difference between herds’ observed and potential milk yield. The second model explained the residual of the first model by feeding and animal-based indicator data. Together, these two models explained 62% of the variance in milk yield differences between herds. Specifically, feeding of the herd was the most important factor, accounting for 67%, followed by the production environment/animal welfare (30%) and finally animal health, assessed through veterinary treatments, explained the remaining 3% of the variance. A poor welfare rating adversely affected milk production. Similarly, a low score for fatness at slaughter, poor milk quality and high mortality all showed a clear negative association with production. It was found that while feeding remains a major factor, production environment and animal welfare also have significant roles to play when it comes to production. Notably, those farms with major animal welfare problems were shown to display milk yield below the Finnish average.

Effect of different milking methods on milk yield and growth of lambs

Indian sheep are unexploited for their milk production potential. Among 43 sheep breeds, Patanwadi is considered to have higher milk yield. With the aim to compare different milking methods to get more yield and better lamb growth, 18 Patanwadi ewes having single born lambs were selected along with their lambs and randomly divided into three groups. Milk yield potential of ewes in Gr A was measured by hand milking method, whereas of Gr B by weigh-suckle-weigh method and of Gr C by hand milking followed by weigh-suckle-weigh method. Average daily milk yield was significantly (P<0.05) higher (658.00±24.60 ml) in Gr C compared to the ewes in Gr A (541.89±20.00 ml). Gr A lambs were fed by bottle feeding method while, Gr B and C lambs by suckling their dams. The lambs in suckling groups (Gr B and C) had significantly (P<0.05) higher growth compared to group A. The pre-weaning average daily gain (ADG) for Gr A lambs was 119 g as compared to Gr B and C (156 g). It was inferred that post-milking suckling method is the better method in Patanwadi ewes with respect to milk yield as well as for higher body weight gain in lambs.

Linkage between predictive transmitting ability of a genetic index, potential milk production, and a dynamic model

With the increased use of information and communication technology-based tools and devices across traditional desktop computers and smartphones, models and decision-support systems are becoming more accessible for farmers to improve the decision-making process at the farm level. However, despite the focus of research and industry providers to develop tools that are easy to adopt by the end user, milk-production prediction models require substantial parameterization information for accurate milk production simulations. For these models to be useful at an individual animal level, they require the potential milk yield of the individual animals (and possibly potential fat and protein yields) to be captured and parameterized within the model to allow accurate simulations of the interaction of the animal with the system. The focus of this study was to link 3 predicted transmitting ability (PTA) traits from the Economic Breeding Index (PTA for milk yield, fat, and protein) with potential index parameters for milk, fat, and protein required as inputs to a herd-based dynamic milk model. We compiled a data set of 1,904 lactations that included different experiments conducted at 2 closed sites during a 14-yr period (2003-2016). The treatments implied different stocking rates, concentrate supplementation levels, calving dates, and genetic potential. The first step, using 75% of the data randomly selected, was to link the milk, fat, and protein yields achieved within each lactation to their respective PTA value, stocking rate, parity, and concentrate supplementation level. The equations generated were transformed to correspond to inputs to the pasture-based herd dynamic milk model. The equations created were used in conjunction with the model to predict milk, fat, and protein production. Then, using the remaining 25% data of the data set, the simulations were compared against the actual milk produced during the experiments. When the model was tested, it was capable of predicting the lactation milk, fat, and protein yield with a relative prediction error of <10% at the herd level and <13% at the individual animal level.

Milk yield potential of prolific avishaan and gmm sheep and their association with overall ewe productivity

A study was undertaken during 2015–2017 to assess the milk yield potential and to estimate the effect of dam's milk yield on ewe productivity efficiency of newly developed prolific Avishaan and GMM (25% Garole-75% Malpura) sheep at ICAR-Central Sheep and Wool Research Institute, Avikanagar, Rajasthan. A total of 369 test day milk records from 34 Avishaan ewes and 199 test day milk yield records from 19 GMM ewes were collected. Average milk recording period in GMM and Avishaan ewes was 66 and 74 days, respectively. Birth and weaning weight data of lambs born to these ewes were also collected. The data were analyzed using the general linear model procedure with different fixed effects and covariates in the model. The least squares means of daily milk yield was 672.73±15.60 g in Avishaan and 531.85±19.77g in GMM ewes. Daily milk yield was significantly affected by stage of lactation, dam's parity and type of birth in both the genotypes. The least squares means of 90-day lactation yield were 63.49±2.46 and 48.40±2.86 kg in Avishaan and GMM ewes, respectively. First parity ewes recorded the lowest lactation yield in both the genotypes. The least squares means of litter weight per ewe at weaning were 21.40±0.72 and 18.47±1.10 kg in Avishaan and GMM ewes, respectively. Positive correlations between ewe's milk yield with litter weight at weaning and average daily gain in litter weight was observed for both the genotypes. It can be concluded that prolific Avishaan sheep has higher milk yield potential compared to GMM sheep and higher milk yield in dam resulted in higher litter weight and average daily gain at weaning.

Effect of the rearing system on financial returns from Murciano-Granadina breed goats

In dairy goats, the kid rearing system can have critical importance in financial returns. Commonly used criteria for the choice of rearing system are not always clear due to the high number of factors involved. The aim of this study was to quantify all those factors to facilitate decision making. So, the effect of two different kid rearing systems, mixed rearing system (MRS) and artificial rearing system (ARS), on milk yield, milk composition and somatic cell count (SCC), milk yield loss at weaning for MRS, kid growth and costs of the different traits on the financial returns in Murciano-Granadina breed goats was studied. Twenty-four goats per group were used. In the MRS, goats reared only one kid, which had free access to goat milk 24 h a day and were weaned at week 6 of lactation, whereas kids in the ARS were separated from their mothers at kidding, colostrum and artificially reared. In both systems, dams were machine-milked once a day throughout lactation and the records took place weekly. Potential milk yield was estimated according to the oxytocin method up to week 12 of lactation, and was similar for both rearing systems, although a 12.3% drop in potential milk yield at weaning was observed for MRS. During the first 6 weeks of lactation, marketable milk was lower for dams in MRS compared to those in ARS (72.1 v. 113.0 l), but similar for the rest of the experiment (101.5 v. 99.4 l, respectively). Marketable milk composition and SCC throughout the 12 weeks of lactation were unaffected by the rearing system. Artificial rearing system entailed an increment in production cost of 22.2€ per kid compared to the rearing by MRS. A similar economic return per goat and kid was obtained from ARS and MRS in this experiment, although, due to one herd’s prolificacy of 1.8, the actual results would be 16.2€ per goat in favour of MRS. The real interest of this experiment may be the possibility of extrapolation to different flocks with diverse levels of milk production, prolificacy and prices and costs for incomes and outputs, to estimate the production system that increases returns. In conclusion, the results showed an increase in the cost of €22.2 per kid bred in the ARS, compared to the MRS, and a final return of 16.2€ per goat in favour of the mixed system.